BUILDING MATERIALS AND STRUCTURES REPORTS

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BMSl Research on Building Materials and Structures for Use in Low-Cost Housing 10(i BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions.. 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 10(i BMS4 Accelerated Aging of Fiber Building Boards IQ^

BMS5 Structural Properties of Six Masonry Wall Constructions 15^ BMS6 Survey of Roofing Materials in the Southeastern States 15(4 BMS7 Water Permeability of Masonry Walls 100 BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel lOjS BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel" Constructions for WaUs, Partitions, Floors, and Roofs lOji BMSlO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co lOjS BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Obnstructions for Walls and Partitions lOjS BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 150 BMS13 Properties of Some Fiber Building Boards of Current Manufacture 100 BMS14 Indentation and Recovery of Low-Cost Floor Coverings 100 BMS15 Structural Properties of "Wheeling Long-Span Steel Floor" Construction Sponsored by

Wheeling Corrugating Co 100 BMS16 Structural Properties of a "Tilecrete" Floor Construction Sponsored by Tilecrete

Floors, Inc 100 BMS17 Sound Insulation of Wall and Floor Constructions 100 Supplement to BMS17, Sound Insxilation of Wall and Floor Constructions 50 BMS18 Structural Properties of "Pre-Fab" Constructions for Walls, Partitions, and Floors Sponsored by the Harnischfeger Corporation 100 BMS19 Preparation and Revision of Building Codes 150 BMS20 Structural Properties of "Twachtman" Constructions for Walls and Floors Sponsored by

Connecticut Pre-Cast Buildings Corporation 100 BMS21 Structural Properties of a Concrete-Block Cavity-Wall Construction Sponsored by the National Concrete Masonry Association 100 BMS22 Structural Properties of "Dun-Ti-Stone" Wall Construction Sponsored by the W. E. Dunn Manufacturing Co 100 BMS23 Structural Properties of a Brick Cavity-Wall Construction Sponsored by the Brick

Manufacturers Association of New York, Inc 100 BMS24 Structural Properties of a Reinforced-Brick Wall Construction and a Brick-Tile CavityWall Construction Sponsored by the Structural Clay Products Institute 100 BMS25 Structural Properties of Conventional Wood-Frame Constructions for Walls, Partitions,

Floors, and Roofs 150 BMS26 Structural Properties of "Nelson Pre-Cast Concrete Foundation" Wall Construction

Sponsored by the Nelson Cement Stone Co., Inc 100 BMS27 Structural Properties of "Bender Steel Home" Wall Construction Sponsored by The

Bender Body Co 100 BMS28 Backflow Prevention in Over-Rim Water Supplies 100 BMS29 Survey of Roofing Materials in the Northeastern States 100 BMS30 Structural Properties of a Wood-Frame Wall Construction Sponsored by the Douglas

Fir Plywood Association 100 BMS31 Structural Properties of "Insulite" Wall and "Insulite" Partition Constructions Sponsored by The Insulite Co 150 BMS32 Structural Properties of Two Brick-Concrete-Block Wall Constructions and a Concrete- Block Wall Construction Sponsored by the National Concrete Masonry Association- 100

[List continued on cover page iii]
UNITED STATES

NATIONAL

DEPARTMENT OF COMMERCE • Jesse H. Jones, Secretary

BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS90

Structural Properties of "PHC" Prefabricated Wood-Frame

Constructions for Walls, Floors, and Roofs

Sponsored by the PHC Housing Corporation

by MAHLON F. PECK, W. GAIL HOBACK

WVINCENT B. PHELAN

with the collaboration of

Carlile P. Winslow, Forest Service, United States Department of Agriculture

ISSUED AUGUST 18, 1942

The National Bureau of Standards is a fact-finding organization;

it does not "approve" any particular material or method of construction. The technical findings in this series of reports are to be construed accordingly.

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • I942

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, WASHINGTON, D. C. • PRICE 15 CENTS
Foreword

This report is one of a series issued by the National Bureau of Standards on the

structural properties of constructions intended for low-cost houses and apartments.

These constructions were sponsored by an organization within the building industry

advocating and promoting their use. The sponsor built and submitted the specimens

described in this report for the program outlined in BMS2, Methods of Determining the

Structxiral Properties of Low-Cost House Constructions. The sponsor, therefore, is responsible for the design of the constructions and for the description of the materials

and method of fabrication. The Bureau is responsible for the testing of the specimens

and the preparation of the report.

This report covers the load-deformation relations and strength of the structural

elements when subjected to compressive, transverse, concentrated, impact, and racking

loads by standardized methods simulating the loads to which the element would be

subjected in actual service.

The Forest Products Laboratory, Forest Service, United States Department of

Agriculture, collaborated in the tests of constructions having wood structural members.

The National Bureau of Standards does not "approve" a construction, nor does it express an opmion as to its merits for reasons given in reports BMSl and BMS2. The

technical facts presented in this series provide the basic data from which architects and

engineers can determine whether a construction meets desired performance requirements.

Lyman J. Briggs, Director.

[II]
Structural Properties of'PHC" Prefabricated Wood-Frame

Constructions for Walls, Floors, and Roofs

Sponsored by the PHC Housing

Corporation

by MAHLON F. PECK, W. GAIL HOBACK

and VINCENT B. PHELAN,

'j:ith the collaboration of Carlile P. Winslow, Forest Service, United States Department of Agriculture

C O N T

Page

Foreword ii

I. Introduction 2

II. Sponsor and product 2

III. Specimens and tests 2 IV. Materials 4

1. Wood 4

2. Insulating board 7

3. Steel 7

4. Paint 7

5. Glue 8

6. Pins 8

7. Bolts 8

8. Washers 8

9. Screws 8

10. Nails 8

11. Felt 9

12. Rubber 9

V. Wall DL 9

1. Sponsor's statement 9

(a) Four-foot wall specimens 9

(6) Eight-foot wall specimens 13

(c) Comments 14

2. Compressive load 15

3. Transverse load 16

4. Concentrated load 17

5. Impact load 18

6. Racking load 19

E N 1 S

Page

VI. Wall DLa 19

1. Sponsor's statement 19

(a) Description 19

{h) Comments 22

2. Racking load . 22

VII. Floor DM 23

1. Sponsor's statement 23

(a) Description 23

(fa) Comments 25

2. Transverse load 26

3. Concentrated load 26

4. Impact load 27

VIII. Roof DN 27

1. Sponsor's statement 27

(a) Description 28

(fa) Comments 30

2. Transverse load 30

3. Concentrated load 30 IX. Roof DO 31

1. Sponsor's statement 31

(o) Description 31

(fa) Comments 31

2. Transverse load 31

3. Concentrated load 32 X. Additional comments bj^ sponsor 32

ABSTRACT

For the program on the determination of the structural properties of low-cost house constructions, the PHC Housing Corporation submitted 33 specimens

representing • PHC" prefabricated wood-frame constructions for walls, floors, and roofs.

The wall specimens were subjected to compressive.

transver.se, concentrated, impact, and racking loads; the floor specimens to transver.se, concentrated, and

impact loads; and the roof specimens to transverse and

concentrated loads. The transverse, concentrated, and

impact loads were applied to both faces of wall speci- mens. For each of the loads, three like specimens were

[1]
tested; the concentrated loads were applied to the same

specimens as either the transverse or the impact loads. The loads simulated the loads to which the elements of a house are subjected in actual service. The deformation under load and the set after the

load was removed were measured for each increment of load. The results are presented in graphs and tables.

I. INTKODUCTION

To provide technical facts on the perform- ance of constructions for low-cost houses, to discover promising new constructions, and

ultimately to determine the properties necessary

for acceptable performance in actual service,

the National Bureau of Standards has invited

the cooperation of the building industry in a program of research on building materials and

structures suitable for low-cost houses and

apartments. The objectives of this program

are described in BMSl, Research on Building

Materials and Structures for Use in Low-Cost

Housing.

To determine the strength of house constructions in the laboratory, standardized methods

were developed for applying loads to portions

of a completed house. Included in this study were masonry and wood constructions of types

which have been extensively used in this coimtry for houses and whose behavior under widely

different service conditions is well Imown to builders and to the public. The reports on

these constructions are BMS5, Structural Properties of Six Masonry Wall Constructions, and

BMS25, Structural Properties of Conventional

Wood-Frame Constructions for Walls, Partitions, Floors, and Roofs. The masonry speci- mens were built by the Masonry Construction

Section of this Bureau, and the wood-frame

specimens were built and tested by the Forest

Products Laboratory at Madison, Wis.

The present report describes the structural

properties of wall, floor, and roof constructions

sponsored by one of the manufacturers in the

building industry. The wall specimens were

subjected to compressive, transverse, concentrated, impact, and racking loads simulating

the loads to which the walls of a house are subjected. In actual service compressive loads on a wall are produced by the weight of the

roof, second floor and second-story walls, if any,

by furniture and occupants, and by snow and

wind loads on the roof. Transverse loads on a wall are produced by wind, concentrated and

impact loads by accidental contact with heavy

objects, and racking loads by the action of wind on adjoining walls. Transverse loads are applied to floors by furniture and occupants;

concentrated loads by furniture, for example,

the legs of a piano; and impact loads by objects

falling to the floor. Transverse loads are applied to roofs by wind and snow; concentrated loads by persons walking on the roof,

and by tools and equipment when the roof is constructed or repaired.

The deflection and set under each increment

of load were measured, because the suitability

of a construction depends not only on its re- sistance to deformation when loads are applied

but also on its ability to return to its original

size and shape when the loads are removed.

II. SPONSOR AND PRODUCT

The specimens were submitted by the PHC

Housing Corporation, Jackson, Miss., and

represented wall, floor, and roof constructions

of prefabricated units marketed under the

trade name "PHC construction." The wall

constructions were prefabricated demovmtable

studs, plates, exterior siding, and interior wall- board panels. The floor was prefabricated

and demountable. It consisted of joists and

girts, with flooring panels on the upper surface

and ceiling panels on the lower surface. The

roof constructions were prefabricated, demountable rafters, headers, and roofing. These ele- ments were fastened by bolts, pins, and steel

clips.

III. SPECIMENS AND TESTS

The specimens represented three elements of a house and were assigned the following symbols: Wall, unbraced, DL; wall, braced, DLa;

floor, DM; roof, 6-in. rafter, DN; and roof, 8-in. rafter, DO. The individual specimens were

assigned the designations given in table I. Except as mentioned below, the specimens were tested in accordance with BMS2. That

report also gives the requirements for the speci- mens and describes the presentation of the

results of the tests, particularly the loaddeformation graphs.

[2]
Table 1.

Specimen designation

Element

Wall. Do.

Do.

Do. Do.

Do. Do.

Do.

Do.

Floor Do

Do.

Roof- Do

Do

Do

Construc- tion symbol DL

DL

DL

DL

DL

DL

DL

DL

DLa DM

DMDM

DN

DN

DO

DO

Specimen

designation

CI, C2, CS.

Tl, T2, TS.

T4, T5, T6.

PI, P2, PS.

PJt, PB, P6.

II, 12, /.?.__ H, IS, 16..

-

PI, P2, PS.

PI, PB, PS.

Tl, T2, TS.

PI, P2, PS.

II, 12, IS.._

Tl. T2, TS.

PI, P2, PS.

Tl, T2, TS.

PI, P2, PS.

Load

Compressive.

-

Transverse do

Concentrated"

do Impact

do Racking

do

Transverse Concentrated a Impact

Transverse

Concentrated. Transverse

Concentrated.

Load applied

Upper end.

Inside face. Outside face. Inside face. niiKiilr fare,

llri.li' I:mv,

Out.--iiir IllCI'. Near upper end. Do. Upper face. Do.

Do. Do.

Do.

Do.

Do.

« The impact and concentrated loads were applied to the same speci- mens, concentrated loads first. b The transverse and concentrated loads were applied to the same

specimens, transverse loads first. Because under compressive load the shortening of the entire specimen may not be proportional to the value obtained from the compressometers attached to the specimen over only a portion of its height, the shortenings and the

sets were measured with compressometers

attached to the steel plates through which the

load was applied, not attached to the specimen

as described in BMS2.

The latex'al dcficcl ions under coiiijjressivi'

loads were measured with a deflectom(!ter of

fixed gage length which consisted of a light

(duralumin) tubular frame having a leg at one

end and a hinged plate at the other. The deflcctometer in a vertical position was attached

to the specimen by clamping the hinged plate near the upper end to one of the faces. The

gage length (distance between the points of support) was 7 ft 6 in. A dial micrometer was mounted on the frame at midlength, with the

spindle in contact with the wall specimen. The

dial was graduated to 0.001 in., and the readings were recorded to the nearest division. There

were two deflectometers on the specimen, one

near each outer stud. This method of measure- ment was used instead of the taut-wire mirrorscale method described in BMS2.

The indentation under concentrated load and

the set after the load was removed were measured, not the set only as described in BMS2.

The apparatus is shown in figure 1. The load was applied to the steel disk, A, to which the cross bar, B, was rigidly attached.

The load was measured by means of the dynamometer, C. Two stands, D, rested on the

Figure 1.

Apparatus for concentrated-load test.

A, steel disk; B, cross bar; C, dynamometer: D, stand; 77, dial micrometer.

3]
face of the specimen, each supporting a dial micrometer, E, the spindle of which was in contact with the cross bar 8 in. from the center of the disk. The micrometers were graduated to 0.001 in., and readings were recorded to the

nearest division. The initial reading (average

of the micrometer readings) was observed under

the initial load, which included the weight of the

disk and the dynamometer. A load was applied

to the disk, and the average of these micrometer readings minus the initial reading was

taken as the depth of the indentation under load.

The sets under the impact loads were measured by means of two set gages instead of one

as described in BMS2. The gages rested on the

loaded face, one over each outer stud or joist.

The readings measured the effect of the impact

loads on the structural members.

The deformations under racking loads were measured with a right angle deformeter consisting of a steel channel and a steel angle braced

to form a rigid connection. The channel of the

deformeter rested on two steel plates, 4 by 4

in., in. thick, and was fastened along the top

of the specimen by two nails extending into the

top plate, the steel angle extending downward

in the plane of the specimens.

The deformations were read to the nearest

0.01 in. on a scale placed near the stop. The

fiduciary mark was on an extension of the steel angle of the deformeter. The gage length (distance from the top of the specimen to the scale) was 8 ft 4% in. The deformeter was used in- stead of the taut-wire mirror-scale described in BMS2.

Because there was no reason to believe that

braces between the studs would affect the compressive, transverse, concentrated, or impact

strength of the specimens DL, the specimens

DLa were subjected only to racking loads.

The tests were begun January 21, 1941, and

completed February 18, 1941. The sponsor's

representative witnessed the tests.

IV. MATERIALS

Information on the materials was obtained

from the sponsor and by inspection of the

specimens. The Forest Products Laboratory

identified the species of the wood. The Paper

Section of the National Bureau of Standards determined the physical properties of the insulating board, and the Engineering Mechanics

Section determined the moisture content of the

wood and insulating board.

1. Wood

Framing.—The wood for the framing was

identified as one of the southern yellow pine

group, No. 1 common, S4S (surfaced four sides),

in the following sizes: fa

^Yzi by 3% in. (nominal 1 by 4 in.) "i 1% by 1% in. (nominal 2 by 2 in.) I 2)4 by in. (nominal 3 by 4 in.) 1^6 by in. (nominal 1}^ by l'_> in.)

1 by 3% in. (nominal 1J4 by 4 in.) 1% by 2% in. (nominal 2 by 3 in.) by 7% in. (nominal 1 by 8 in.) 1% by 3H in. (nominal 2 by 4 in.)

'^Yi2 by 5% in. (nominal 1 by 6 in.) 1% by 5% in. (nominal 2 by 6 in.) 1% by 7% in. (nominal 2 by 8 in.) Phjtvood, exterior type.—Douglas fir, two

thicknesses, % in. and }i in., thi-ee-ply, bonded

with phenolic resin (Resinous Products and jl Chemical Co.) by hot-pressing, sanded two I sides. The plywood complied with Commer- j cial Standard CS45-38, Douglas Fir Plywood,

wallboard grade. U. S. Plywood Corporation. \ Plywood, inferior type.—Douglas fir, % in. i thick, three-ply, bonded with water-resistant

protein glue having a soya-bean and casein i base, sanded two sides. The plywood complied

with Commercial Standard CS45--38, Douglas

Fir Plywood, wallboard grade. U. S. Plywood

Corporation. | ,: Flooring panels.—Duali-faced Douglas fir j \ plywood, % in. thick, five-ply, bonded with

water-resistant protein glue having a soya-bean i and casein base, sanded two sides. U. S. Ply- I wood Corporation. I Basemolding.—Southern yellow pine, select,

| grade B or better. I Corner molding.—Birch, select, grade B or

better. Spacer blocks.—Southern ^^ellow pine, No. ] common, by 1% in. (nominal 1 by 2 in.), S4S.

After each wall, floor, or roof specimen was

tested, one face was i-emoved to expose the

framing and samples of the wood were taken

for identification of the species. Photographs were made of each specimen showing the failures and the character of the wood in the framing.

Figures 2 to 6 are typical specimens.

[4]
The moisture content of the wood (except

moldings and spacer blocks) is given in table 2. An electric moisture meter was used for

Table 2.Moisture content of the wood

[Determined the day the wall, floor, or roof specimen was tested]

Wood

Framing, southern pine

Cli|i rails, sdutliem pine

Siding, Douglas fir plywood.

RiKifing, Douglas fir plywood

\\ alll)ciard, Douglas fir plywood

Ceiling, Douglas fir plywood

Flooring, Duali-faced Douglas fir plywood

" Based on weight when ovendry.

Construction symho!

[DL \dm

\dn

\do

DL

DN

DO

DL

[DN

\D0

DL

DM

DM

Moisture content

Mini- Maxi- Aver- mum mum age

Percent Percent Percent

7 10 8

7 9 8

7 8 7

7 10 8

8 7 8 7

7 9 7

4 B 4

4 7 5

3 5 4

0 5

(i 6 6

5 6 (i

Figure 2. Wall DL.

Typical tour-foot specimen.

Figure 3.—Wall DLa.

Typical eight-foot specimen with braces.

[5]
determining the moisture content. To cali- brate the meter for southern pine, 136 samples

from the wall, floor, and roof specimens were

(hied in an oven at 212° F until the weight was

constant. The moisture content was the dif- fei'ence between the initial weight and the

weight when ovendry, expressed as a percentage

of the weight when ovendry. The average

value for the southern pine samples was 0.1 greater than the average of the meter readings on the same samples. The moistin-e contents

in table 2 were obtained by adding 0.1 to the

average of the metei- readings and rounding the

results to the nearest whole percent. The

moisture content was determined on each piece

of framing in each specimen and on three clip

rails in each wall and roof specimen. The

determinations on the plywood (siding, roofing,

wallboard, flooring, and ceiling) were made by

drying one sample from each specimen in an oven at 212° F until the weight was

constant.

Ficrin. 4.Floor DM.

Typical specimen.

Figure 5.—Roof DN.

Typical specimen.

• "

K m » -ft

Figure %.~~RooJ DO.

Typical specimen.

[6]
2. Insulating Board

The insulating board was made from wood

fibers, produced by a cold-grinding process,

felted into a rigid board. The fibers were

chemically treated and intimately mixed with

finely divided asphalt before felting to in- crease the strength, water resistance, and re- sistance to rot and termites. One surface of the boards had the appearance of closely woven

fabric, designated "linen texture"; the other

surface had the appearance of loosely woven

fabric, designated "burlap texture." There

were two thicknesses, 1 in. and IK in. The

Insuiite Co., "Graylite." The physical properties given in table 3 were

determined on undamaged samples taken from

the wall specimens after testing. The linear

expansion, transverse strength, and deflection were determined in accordance with Federal

Specification LLL-F-321a, Fiberboard; Insulating. For these properties the board complied with the requirements for class A. The

values furnished by the sponsor for the tensile strength, water absorption, and thermal conductivity also comply with the requirements

for class A.

The moisture content of the insulating board was determined on one sample from each wall

and roof specimen by drying at 212° F until the

weight was constant.

Table 3.Physical -pruperties of insulating board, 1 in. and lYi in. thick

[The samples were taken from the wall and root specimens after they had been tested]

Property

Value

1 in. IH in.

Transverse strength, long, direction " lb,. Deflection at rupture in__ Linear e.xpansion for 45% change in relative humidity, long, direction - -percent-. Density ----Ib/tt.S-- Moisture content, based on weight when ovendry

percent..

Tensile strength lb/in. Water absorption, by volume. percent.. Thermal conductivity (Btu/hr ft^) (°F/in.)..

90

0.4

.1 20

4. 7

b 375

l>5

i>0. 33

Ill0.4

. 1 18

5.0

i> 375

b 5 bO. 33

» Span, 12 in.; width of specimens, 3 in.

I" Value furnished by sponsor.

3. Steel

The steel was basic open-hearth; hot-rolled

and pickled sheet steel and cold-rolled spring

steel. The sheet steel was in six thicknesses.

Nos. 11, 12, 14, 16, 18, 20, black; Nos. 10 and

18, galvanized; U. S. Standard Gage. T!ie

spring steel was in three thicknesses, Nos. 13,

20, and 24, black, U. S. Standard Gage.

The mechanical properties are given in table 4 and the chemical composition in table 5. Kilby Steel Co., Anniston, Ala.

Table 4.

Mechanical properties of the steel

Steel

Tensile strength Elongation in

2 in. Minimum Maximum

Slicet steel, hot-rolled . Spring steel, cold-rolled

Ib/in.i

48, 000 58, 000

80, 000

Percent

22

18

Table 5.

Chemical composition of the steel

Element

Content

Hot-rolled Cold-rolled

Minimum Maximum Minimum Maximum

Carbon

Manganese.

Pho.sphorus

Percent

0. 05 .30

Percent

0. 15 .60

.45 .055

Percent

0. 10 .30

Percent

0.20

.60

.45 Sulfur .055

Galvanizing.—The sheets were "hot-dipped"

in molten zinc and complied with Navy Specification 47S10D, Commercial coating. Class D.

Foryning.—The steel was sheared, punched,

and cold-formed with shears and presses. Painting.—The black sheet steel and spring

steel were prepared for painting by dipping in

mineral spirits.

4. P.'VINT

Filler and paints for wood imris.—The formula

for the wood filler is given in table 6 and the

formidas for the exterioi' primer, exterior wall

paint, interior primer, interior wall paint, and

roof paint are given in table 7. Carpenter &

Morton Co., Boston, Mass.

Table 6.Formula for wood filler "Carmote Cealcote''

Ingredient Content, by

weight

Percent Synthetic phenolic resin- . 11 Processed vegetable oil ... 19 Drier and thinner ... 70

466967°—42 2 [7]
Table 7.

Formulas for paints

Name

Extorior primer, "Safe-T- Primer"

Exterior wall paint. "R. H.

P. White B800"

Interior primer, "Carmote

Primer and Sealer"

Interior wall paint, "Waldorf Flat White B9384" _ _ _

Roof paint, "Roof Green"

Content, by weight

Pigment

Percent

60.5

66.0

Vehicle

Percent

39. 5

38.0

67.0

Pigment

Ingredient

Lead carbonate Titanium dioxide- _ Silica and extender.

Basic sulfate white lead Zinc oxide Titanium pigment, magnesium base. Titanium dioxide. .

/Titanium dioxide..

\ Calcium carbonate.

i (Titanium pigment, calcium base.

34 0 j<Zinc oxide

! I Extender {Black iron oxide Carbon black. , CP. chrome green.

Silicates .

Content by

weight

Percent

64. 5

12. 7 22.8

27.0

27.0 42.0

4.0

18. 2 81.8

82. 0 4.0

14.0

32.0

14.0 46.0

8.0

Vehicle

Ingredient

I Linseed oil (Drier and thinner

Linseed oil Drier and thinner

(Processed drying oils <Modifled phenolic resin [Drier and thinner

] Processed drying oils... >Resin

) Drier and thinner

[Synthesized oil Linseed oil Drier and thinner

Content by

weight

Percent

70.0

30. 0

90.0

10. 0

34.0

14.0 52.0

31. 0 2.0 67.0

28. 0 52.0 20.0

Metal primer.—Gilsonite and asphalt in a mineral solvent. Glass and Biiildez's Supply

Co., Anniston, Ala.

Stain..—Penetrating oil stain. The formula

and the name of the maker were not furnished

by the sponsor.

5. Glue

Elastic cemevt. —Reclaimed rubber and resin

dissolved in a volatile hydrocarbon. Minnesota Mining and Manufacturing Co., "Elastic

Cement E. C. 194, Type 3 M."

6. Pins

Steel. —Basic electric furnace, hot-rolled, Kein. diam by 5/2 iu. long. Kilby Steel Co.

7. Bolts

Machine.—/g-iu. diam, 4 in. long, mild steel,

square head, National Coai-se (N. C.) 16 threads

per inch, threaded IK in., blued. Nuts: mild

steel, square, loose fit. Machine.—%-in. diam, 6 in. long, mild steel,

square head. National Coarse (N. C.) 16 threads per inch, threaded 3% in., blued. Nuts:

mild steel, square, loose fit. Hook.—Mild-steel rod %-in. diam, No. 11 U. S. Standard Gage, National Coarse (N. C.)

16 threads per inch, threaded in., welded to sheet-steel head, blued. Nuts: mild steel, square, loose fit.

8. Washers

ji in. round.—Sheet steel, 1-in. diam, No. 14

U. S. Standard Gage (0.0766 in).

ji in. square.—Galvanized sheet steel, Iji by

lYi in., No. 12 U. S. Standard Gage (0.1072 in).

9. Screws

Lag.—Mild steel, /g-in. diam, 7 threads per

inch, square head, two lengths: 2 in., threaded

Iji in., blued; 3 in., threaded 2 in., bright.

Wood.—Mild steel, two sizes: No. 10 Screw

Gage (0.1900-in. diam), two lengths, 1% in. and 3 in., 13 threads per inch, flat head, bright;

No. 12 Screw Gage (0.2160-iu. diam), % in. long, 11 threads per inch, round head, blued.

10. Nails

The nails were made from steel wu"e and are described in table 8.

Table 8.Description of nails

steel Wire Gage Type Size Length Finish No. Diameter

Penny In. Basket Vs 18 0. 0475 Bright. Brads . Vs 16 .0625 Do.

Casing.. 5 IM 14 .080 Do.

Do.-.. ._ 6 V/s 13 .0915 Do. Do 6 13 .0915 Cement-coated. Do 8 1132 . 113 Bright. Common . 3 14 .080 Zinc-coated. Do 10 3 9 . 1483 Do.

Finishing _ . 2 1 16}^ . 0583 Do.

Roofing... .- - 2 1 12 . 1055 Do. Do 4 1>2 nvi . 113 Do.

[8]
11. Felt

Felt weatherstrip, ^Ke in. Avide, 50 percent

wool, 50 percent cotton. Thermowool Products Co., " ^Ka ill. Soft Grey Felt Weatherstrip."

12. Rubber

Rubber- strips.—New Du Pont sponge rubber.

Kastar Inc., "Stix-on."

V. WALL DL

1. Sponsor's Statement

Wall DL was a prefabricated, demountable

wood-frame construction having- an outside face

of plywood and insidating-board siding- iiu<l an

inside face of plywood wallboai-d

.

The price of this construction in Wasliington,

D. C, as of ,My 1937 was $0.58/fl-.

(a) Four-Foot Wall S/)eci7nens

The 4-ft wall specimens, shown in figure 7, were 8 ft 4% in. high, 5 ft 0 in. wide, and 5% in. thick. Each specimen consisted of a wood

frame to which the faces were attached. Tlie

frame was three prefabricated wood studs. A,

attached to a wood floor plate, B, and top plate,

C, by hook bolts. The outside face was 19 pieces of prefabricated plywood and insulatingFiGT RE 7. —Four-foot wall specimen DL.

A. stud; B. floor plate; C, top plate; D, siding; E, base-molding; F, wallboard panels; G, spacers; //, blocks.

[9]
board siding, D, attached by spring-steel clips.

The inside face consisted of one piece of

prefabricated basemolding, E, attached by

spring-steel clips, and four prefabricated plywood wall-board panels, F, attached by sheetsteel clips. The overhanging edges of the faces were supported by spacers, G, fastened to the

outside face and to blocks, H, on the inside

face. Studs.—The studs. A, shown in figure 8, were

prefabricated members each consisting of two

southern-pine boards, /, ~%2 by 3% in. (nominal

1 by 4 in), 7 ft l\% in. long, and five southernpine blocks, J, 1% by V/i in. (nominal 2 by 2 in),

6 in. long. The blocks were centered 9% m.,

2 ft 2% in., 3 ft 7% in., 5 ft l)i in., and 6 ft 10% in. from the lower end of the stud. Each block was fastened to each board by two 8d casingnails. Seven holes, Ke-in. diam, extended

tlu'ough the boards at midwidth. The dis- tances of the holes from the lower end of the

studs were 2% in., 1 ft 1%6 in., 2 ft %){ in., 3 ft lli%6 in., 5 ft 5}^ in., 6 ft 10%6 in., and 7 ft 8% in. The holes were for pins to attach the stud rails. There were three steel pins, K, Ke-in. diam,

5^2 in. long, one through each end hole and one

through the hole at midlength. Each end pin

fastened a southern-pine tenon, L, 1% by 1% in.
(nominal 2 b}' 2 in), 1% in. long, whicii extended

2% in. from the end of the stud and fitted the

mortises in the plates. The inner surface of each board had two grooves (saw Iverfs), Ke by

%2 in. deep and ^Ke in. from each edge, to receive

clips for attaching the inside face. The studs were covered with one coat of white exterior primer, applied with a brusli. A sheet-steel bearing plate, M, No. 12 U. S. Standard Gage (0.1072 in), was on each end of the stud and fastened by one 5d casing nail

in each board.

.A sheet-steel stud rail, A^, No. 18 U. S. Standard Gage (0.0490 in), extended across the outside face of each stud and 1% in. beyond the

lower end of the stud. Each stud rail was

attached to each side of the stud by three sheetsteel stud-rail clips, 0, No. 12 U. S. Standard

Gage (0.1072 in), which hooked over the pins;

extended through slots, % by 1)2 in., in the

flanges of the stud rails; and were held by a

sheet-steel wedge, P, No. 11 U. S. Standard

Gage (0.1225 in). Thu-teen holes, 1% by 3 K in., in the stud raU were spaced T^%i in. on centers,

the lower hole centered 8)4 in. from the lower

end of the rail. The stud rails were for attaching the siding.

The projecting edge of the four sheet-steel

prong clips, Q, No. 16 U. S. Standard Gage

(0.0613 in), on the inside face of the stud, ex- tended into the groove in one board and the

prong into the other board. The clips were

centered 10% in., 2 ft 10% in., 5 ft 2% in., and

7 ft 3% in. from the lower end of the stud and

were for attaching the wallboard panels.

The edges of the spring-steel molding clip, R,

No. 20 U. S. Standard Gage (0.0368 in), at the

lower end of the inside face of each stud, ex- tended into the grooves in the boards. The

clip was for attaching the basemolding.

Each steel part, except the pins, was covered

with one coat of blaclt metal primer, applied

by dipping.

Plates.—The floor plate and the top plate, B

and C, shown in figiu-e 9, were southern pine,

2K by 3K in. (nominal 3 by 4 in), 5 ft 0 in. long.

There were three mortises, 1% by 1% in., at midwidth of each plate, one centered 10 in. from

each end and one at midlength, and two holes,

'/i(,-vs\. diam, at midwidth of each plate adjacent

to each mortise.

Each plate was covered witli one coat of wliite exterior primer, applied with a brush.

Each mortise-and-tenon joint in the frame was fastened by two hook bolts, S (fig. 8), one on each side of the stud. The hook was sheet

steel. No. 11 U. S. Standard Gage (0.1225 in), to which a steel rod, /8-in. diam, 4 in. long, was

lapped 1/^6 in. and fastened by two fillet welds.

The thread on the end of the rod, in., National

Coarse (N. C.) 16 threads per inch, was % in. long.

The hook bolts were covered with one coat of black metal primer, applied by dipping.

This bolt hooked over the pin in the stud,

extended into the hole in the plate, and was

fastened by a %-in. round washer and a square

nut coimtersunk into the plate.

Siding.—The siding, D (fig. 9), was pre- fabricated and was in two lengths, 5 ft 0 in. and

2 ft 6 in. Each piece had an outside face of

plywood and an inside face of insulating board.

The outside face of each piece of siding was

Douglas fir plywood, T, exterior type, % in. thick and 9)4 in. wide. The inside face was

insulating board, U, 1 in. thick and 5% in. wide,

fastened to the plywood, the upper edges flush,

by glue. The southern-pine clip rail, V, 1/U by

l^i'e in. (nominal Iji by IK in), along the lower

edge of the insulating board was fastened to the

plywood by glue and by 3d galvanized common

nails, spaced about 7)2 in., extending through

the plywood into the clip rail. The spongerubber strip, W, ji in. thick and % in. wide,

along the lower smiace of the chp rail adjacent

to the plywood was fastened by glue and by

%-m. basket nails spaced about 7}i in. This

strip was for closing any air gajD between over- lapping courses of siding.

In the 5-ft 0-in. siding, the insulating board,

the clip rail, and the rubber strip were each one

piece 5 ft 0 in. long, but the plywood was two

pieces, 1 ft 1% in. and 3 ft 10}^ in. long, the ends

butted. There was a groove (saw kerf), Ke in.

b}^ Yii in. deep, along each butted end at midthickness. The butted ends were alined by a galvanized sheet-steel spline, No. 18 U. S. Standard Gage (0.0490 in), % by 9% in., in the

grooves.

In the 2-ft 6-in. siding, the plywood, insulating, board, clip rail, and rubber strip were each one piece 2 ft 6 in. long. The butted ends of the

1 ]
siding were alined by a sheet-steel spline in the

groove (saw kerf) at midthickness, in. by

in. deep.

The outer surface of the siding was covered

with one coat of white exterior primer and one

coat of white exterior wall paint, applied with a brush.

Spring-steel siding clips, X, and half siding

clips, r, No. 24 U. S. Standard Gage (0.0245

m), were fastened to the lower surface of the

clip rail by a %-in. round-head wood screw

through each hole in the clip. The clips were

for attaching the siding to the frame. On each

piece of 5-ft 0-in. siding there were three siding

clips, A', centered 10 in., 30 in., and 50 in. from

the end. On each piece of 2 ft 6 in. siding there was one half siding clip, Y, and one siding clip,

X, centered ^Ym in. and 20 in., respectively, from

the butting end.

The siding clips were covered with one coat

of black metal primer, applied by dipping.

The siding was in alternate courses of 5-ft

Figure 9.Details of rvaU DL. B and C, plate; D. sidinfr; T, plywood; U, insulating board; V, dip rail; W, rubber strip; E, basemolding; Z. molded strips: AA, plywoed; X

and Y, siding clips; AC, wedge clip.

12
0-in. and 2-ft 6-in. pieces, attaclied to the frame

by the siding chps which extended over the

lower edge of the holes in the stud rails. The

butted ends of the 2-ft 6-in. pieces were alined

by splines, lilie those in the 5-ft 0-in. pieces, in the grooves. Each of the two southern-pine blocks, \ '% by

1% in. (nominal 2 by 2 in), along the top edge

of the upper course of siding was fastened to the

top plate by two 3-in. fiat-head wood screws. These blocks were to prevent displacement of the siding upward and detachment from the

studs.

Basemolcling.—The basemolding, E, (fig. 9), was prefabricated and consisted of two molded

strips of southern yellow pine, Z, 5 ft 0 in. long,

backed by a piece of Douglas fir plywood, AA,

exterior type, % in. thick and 5 ft 0 in. long.

The molded strips were fastened by glue; the

backing was fastened by glue and by 2d finish- ing nails. Three rows of nails, one along each

edge and one at midwidth, extended through

the backing into the strips. The nails were

spaced about 7}i in. The groove (saw kerf) % by K in. deep in the

lower edge of the molding, ji in. from the outside face, held the molding clips.

A 45"^ rabbet, in. deep, in the upper edge

of the molding, % in. from the outside face,

received the beveled end of the wallboard

panels.

The basemolding was covered with one coat

of white interior primer, applied with a brush.

Wallboard panels.—The wallboard panels, F,

shown in figure 7, were prefabricated members.

The panels were Douglas fir plywood, interior

type, /8 in. thick, 7 ft lYs in. long, two full-width

and two half-width panels on each specimen.

The full-width panels were 1 ft 8)4 in. wide (face

width 1 ft 8 in). A rabbet, % by ji in., in each

edge on opposite faces joined the panels. A

groove (saw kerf), Ke by 732 in. deep, was in one

edge for attaching the panels to the studs.

Along each edge of the inside face of the panels was a 45° bevel % in. deep, and along each end

of the outside face a 45° bevel % in. deep.

The inside face of each panel was treated with one coat of wood filler and covered with one

coat of white interior primer and one coat of white interior wall paint, applied with a brush.

Two felt strips ^Ke in. wide, were on the outside face of each panel, one alojig each edge

approximately 1 in. from the bottom of the bevel

and attached by glue.

The half-width wallboard panels were the same as one-half of a full-width panel divided

along the longitudinal center line. There were

four southern-pine blocks, H (fig. 7), by

1/8 in. (nominal 1 by 2 in), 3 in. long, along the

overhanging edge of each half-width panel.

The blocks were centered Qji in., 2 ft 4}$ in., 4 ft 9% in., and 7 ft 3)^ in. from the lower end

of the panel. Each block was fastened by

three 2d finishing nails extending through the

wallboard into the block. The blocks were for fastening the spacers to the inside face and are not used in a house.

One edge of each panel extended into the

rabbet of the adjacent panel. The other edge was attached to the frame by four sheet-steel

wedge clips, AC, No. 20 U. S. Standard Gage

(0.0368 in.), shown in figure 9. One edge of each wedge clip extended into the gi'oove in the

wallboard panel and the other edge (wedge

shaped) hooked over a similar edge of a prong

clip in the frame.

The wedge clips were covered \\dth one coat

of black metal primer, applied by clipping.

Spacers.—The spacers, G (fig. 7), were southern pine, -%-2 by 1% in. (nominal 1 by 2 in.), 5%

in. long. Four spacers on each edge of each

specimen were centered 1 ft 0% in., 2 ft 10%6 in., 5 ft 2^%6 in., and 7 ft 7"i6 in. from the lower end

of the specimen. Each spacer was fastened by

two V/o in. flat-head wood screws, one extendmg

into a clip rail and one extending into a block

fastened to the wallboard. No spacers are used

in a house.

(b) Eighf-Foot Wall Specimens

The 8-ft waU specimens, shown in figure 10, were 8 ft 4% in. high, 8 ft 11 in. wide, and 5% in. thick. They were similar to the 4-ft specimens

except that there were six studs. A; the siding,

D, was m two lengths, 5 ft 0 in. and 3 ft 4 m.; and there were five full-width wallboard panels,

F, and one panel in. wide. Spacers were

not necessary. The floor plate, B, and the top plate, C, were

each 8 ft 11 m. long, and the basemoldmg was

8 ft 7^8 in. long. All parts were painted as in the 4-ft specimens.

[13]
(c) Comments

Walls DL are used mostly for small dwellings

ond similar buildings of one or two stories. The

walls are assembled on the building site from

standardized prefabricated parts which are demountable. The height of the wall is 8 ft and

the stud spacing 20 in. The width of the wall

is any multiple of this spacing.

Door and window openings are 40 in. wide

(two stud spaces), the center stud being cut and

wood sills and lintels fastened to the adjacent

studs by sheet-steel angles and wood screws. The doors and windows usually are wood of commercially available designs.

Siding for the exterior of the building is available in lengths of 20, 40, 60, and 80 in. Siding

is used also for gable ends, where it is placed

Figure 10.

Eight-foot wall specimen DL.

A, stud; B, floor plate; C, top plate; D, siding; F, wallboard panels.

14
vertically and attached to the ceiling joists and

rafters. Wallboard for the interior extends from floor to ceiling and is 20 in. wide (one stud space).

Table 9.

Structural properties of walls DL and DTm

[\V( isht, based on face area: DL, 0.03 Ib/ft^; DLa, fi.98 lb/ft-'

compressive

2. Compressive Load

Wall specimen DL-C2 under

load is shown in figure 11. The results for specimens DL-Cl , C2, and

CS are given in table 9 and in figures 12 and 13. The compressive loads were applied 1.21 m.

(one-third the thickness of the frame) from the

inside face of the studs. The shortenings and

sets (fig. 12) are for a height of 8 ft 4% in. The

Construc- tion symbol

Compressive load "

Transverse

load; span,

7 ft 6 in.

Concentrated

load; diam of

steel disk,

1 in.

Impact

load; span 7 ft 6 in.; weight

of sandbag, 601b

Hacking

load

1

Specimen .SX1

Specimen Maximum

load

Specimen Maximum

load

1

Specimen 1

Maximum

hi-ight

of

drop

a

Maximum

load

DL

c; \C2

[C3

^Kipslft

4. 92 3.60

4.86

TlTZ

TS

IbjfV- 171.7

150.

216.5

PIP2PS

lb743

5.50 700

11m

IS

ft1010

10

ElR2

RS

^Kivlft

0. 123

. 1.59

. 150 Average

DL

4. 46 179.5 664 10 0. 144 ¥

'n

T5

T6

157. 0

165. 5

256. 5

Pi

PBP6

837

1, 060 876 UIB16

1010

10 A verage

DLa

193.0 924 10 RlR2RS

0. 425

.442

.450 \---

Average

0.439

» The compressive loads were applied 1.21 in. (one-third the thickness of the frame) from the inside face of the studs.

^ A kip is 1,000 lb.

5

%

1^ J

2

• o

•

•

1e •

oo /—o

0 —• m 3 </ 0

i oc ' o

/

b

/

1 y—O-H

o • cry -/—

•a g 4/

' o

Figure 11. spi'cimen DL-C2 under compressive

load. A, compressometer; B, (.ietlectonieter.

0 a 0.2 shorfen/ng in.

Figure 12.Compressive load on wall DL.

Load-shortening (open circles) and load-set (solid circles) results for speci- mens DL-Cl, C2, and CS. The load was applied 1.21 in. (one-third the

thickness of the frame) from the inside face. The loads are in kips per

foot of actual width of specimen.

466967°—42 3
^ 4

>i J

I

0

• 0

1 O /(

O 0

)0

[ 0 /

^ •

\

1 (; o o

1 O /

°

1 •o

0 1

/

-co— hr /<D

•Q

4

i/a>

!> -OJ 0 0./ 02

/ofera/ c/ef/ec//on /n. Figure 13.

Coinpirfisive load on wall DL.

Load-lateral deflection (open circles) and load-lateral set (solid circles) results for specimens Dlr-Ct, C2, and CS. The load was applied

1.21 in. (one-third the thickness of the frame) from the inside face. The

loads are in kips per foot of actual width of specimen. The deflections and sets are for a gage length of 7 ft 6 in., the gage length of the deflec- tometers.

lateral deflections (fig. 13) are plotted to the

right of the vertical axis for deflections of the

specimens toward the outside face and to the

left for deflections toward the inside face. The speed of the movable head of the testing

machine was adjusted to 0.072 in./min.

Under loads of 4.68, 3.20, and 4.60 kips/ft on

specimens DL-Cl, 02, and CS, respectively,

the top plate began to crush locally at the inside

edge of the studs.

Under the maximum load, the greatest crushing was }i in. No other effects were observed

except that one board of an outer stud in specimen CS cracked longitudinally at the upper end.

3. Transverse Load

The results of the transverse loads are shown

in table 9 and in figure 14 for v/all specimens

DL~T1, T2, and T3, loaded on the inside face,

and in figure 15 for specimens DL-T/f, T6, and

T6, loaded on the outside face. The speed of the movable head of the testingmachine was adjusted to 0.128 in./min.

The transverse loads were applied to the in200

\ /60

'\/^o

\

40

0

1 <

-0

p

1

—o—

1 • •

—o—

/ —

<

-o

1

1•

171/

0 / 2 J

c/ef/ecZ/on /n.

FifiTTRE 14. —Transverse load on wall DL, load applied

to inside face.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens DL-Tl, T2, and T3 on the span 7 ft fi in.

side face (wallboard) of specimens DL~T1 , T2,

and T3. For each specimen, as the loads in- creased the studs deflected and the exposed

/60

120

^ 80

\

I 40

O

r* 1

-•

c

o

)

1

«

oo—

V

o /o

oo

1 y

\ DL-4 0 as /.o /5

c/ef/ecfion /n. Figure 15.—Transverse load on wall DL, load applied

to outside face.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens DL-T4, TS, and T6 on the span 7 ft 6 in.

[16]
edges of the siding between the loading rollers separated outwardly from the adjacent siding.

Under a load of 60 lb/ft- on specimen Tl , the

separation was noticeable, and under 70 lb/ft- measured % in. m some places. The separation

of the siding in this specimen was typical of that

in specimens T2 and T3. Under a load of 123

Ib/ft^ on Tl , an outer stud cracked at a knot, and

imder the maximum load split longitudinally

through the hole at midlength.

One piece of siding in specimen separated

from the adjacent piece under a load of 40 Ib/ft^ because, when assembled, the siding clips had

not engaged the stud rails. Under a load of 95

lb/ft", an outer stud cracked at three knots.

Under the maximum load, this stud ruptured

and the middle stud cracked. In specimen T3 an outer stud cracked at a load of 212 Ib/ft^ Under the maximimi load,

all the studs ruptured.

After the maximum load had been applied to each of the specimens, the wedge clips were

loose. The transverse loads were applied to the outside face (siding) of specimens DL-T4, T5, and

T6. In specimen T4 one outer stud ruptured

at midspan under a load of 70 Ib/ft^ At 80

Ib/ft^ a half-width wallboard panel separated

from an outer stud at midspan. Under the

maximum load the middle stud also ruptured. In specimen T5 under a load of 129 Ib/ft^, one

outer stud ruptured at a knot near midspan.

At 162 Ib/ft^ the ruptured stud displaced a half- width wallboard panel. Under the maximum

load, the middle stud ruptured near the loadingrollers. In specimen T6 one outer stud cracked

under a loading roller at a load of 152 Ib/ft^; and under 243 lb/ft- the other outer stud cracked

at midspan. Under the maximum load, all the

studs ruptured and there was a separation of the

wallboard along one outer stud.

4. Concentrated Load

Wall specimen DL~PJf under concentrated

load is shown in figure 1 . The results are given

in table 9 and in figure 16 for specimens DL-Pl,

P2, and PS, loaded on the inside face, and in figure 17 for specimens DL~P4, P5, and P6,

loaded on the outside face. The concentrated load was applied to the

inside face (wallboard) of specimens PI, P2,

0.2 0.4 /nc/en/a//on

FifiURE 16.

Concentrated load on wall DL, load applied

to inside face.

Load-indentation (open circles) and load-set (solid circles) results for speciTnens DL-Pl, P2, and PS.

and PS midway between two studs and 20 in. from one end of the specimen. Under the

maximum load on each specimen the disk

punched through the wallboard.

O.Z 0.4 inc/enfofion /n

Figure 17.- -Concentrated load on wall DL, load applied

to outside face.

Load-indentation (open circles) and load-set (solid circles) results for specimens DL-P4, P5, and P6.

[17]
The concentrated load was applied to the

outside face (siding) of specimens jP^; P5, and

P6 midway between two studs and 5K in. fi'om

the exposed edge of a piece of siding. Under a load of 800 lb. on specimens and P6, the

siding cracked adjacent to the disk. Under the

maximum load on each specimen, the disk

punched through the siding.

5. Impact Load

Results of the impact-load test are given in

table 9 and in figure 18 for specimens DL-Il,

12, and 13, loaded on the inside face, and in

figure 19 for specimens DL-I4, 15, and 16,

loaded on the outside face. The impact loads were applied to the inside

face (wallboard) of specimens DL-Il, 12, and

IS. The sandbag struck the center of the specimen over the middle stud. On specimen

DL~I1, after a drop of 3.5 ft, a half-width wallboard panel was loose. One piece of siding

separated from the studs at a drop of 5.0 ft because, when assembled, none of the clips had

engaged the stud rails. Additional pieces of siding fell olf as the height of drop was increased.

Table 10.

Effects of impact load on wall specimens

DL-I4, 1^3, and 16, loaded on the outside face

def/ecf/'on

Figure 18.Impact load on wall DL, load applied to inside face.

Height of drop-deflection (open eireles) and height of drop-set (solid

circles) results for specimens DL-Il, It, and IS on the span 7 ft 6 in.

Specimen IJ, Specimen 75 Specimen IS

p. p. 0. o o o

Description of effects a

•a a

T3 c ° •2 •2 C •2 o

o

<n Q p Mw Q

u in

.

// in. ft in. Outside stud ruptured at knot__ 4.0 1. ?3 5.0 1.61 3.5 1. 11 All studs ruptured--- - 10. 0 4.31 10 0 Face loaded: One or more nails pulled from clip rails 9.5 4.00 8.5 6.5 1.61 Separation ofadjacentpieces

of sidinsr 10.0 4. 31 8.5 Clip rail ruptured where

sandbas struck- -- --- 10.0 4. 31 10.0 Face not loaded: Wallboard separated from

a stud - - - - - 4.0 1. 23 5.0 1.61 5.0 1.42 Wallboard separated from

all studs 6. 5 2.31 9.0 6.0 1.56

A full-width wallboard panel separated from

the studs at a drop of 7.0 ft. After a drop of 9.0 ft the middle stud was cracked where the

sandbag struck. In specimen 12 after a drop of 6.0 ft the basemolding was loose, and after a drop of 7.0 ft a half-width wallboard panel separated from an

outer stud and a piece of siding began to sepa0 / 2 3 4

c/ef/ecf/on /n. Figure 19.

Impact load on wall DL, load applied to outside face.

Height of drop-deflection (open circles) and height of drop-set (solid

circles) results for specimens DI^U, 15, and 16 on the span 7 ft 6 in.

[18]
rate from the clip rail. After a drop of 10 ft the studs were undamaged.

In specimen IS after a drop of 9.0 ft the basemolding chps were loose. After a drop of 10 ft, three siding chps were disengaged and the

middle stud was ruptured.

The impact loads were applied to the outside

face (siding) of specimens DL-I4, 15, and 16. The sandbag struck tlie center of the specimen

over the middle stud,

table 10. The efl'ects are given m

6. Racking Load

The results of the racking load on specimens

DL-Rl , R2, and R3 (without braces) are given

in table 9 and in figure 20. At loads of 0.075, 0.075, and 0.100 kip/ft on

specimens DL~RI, R2, and R3, respectively,

there was horizontal displacement of adjacent

pieces of siding and %-in. or more vertical dis- placement of the wallboard panels.

The maximum load on each specimen was

taken as the load under which the deformation was 7 in., in a height of 8 ft. Under the maximum load on each specimen, there was increased

displacement of adjacent pieces of siding and of the wallboard panels.

I

• • c 0

* • 0 0

/

/ -Ay

mp

' /

tc/eformaf/'on /n./dff

Figure 20.

Racking load on wall DL.

Load-deformation (open circles) and load-set (solid circles) results for specimens DL-Rl, RS, and R3. Th.e loads are in kips per foot of actual width of specimen.

VI. WALL DLa

1. Sponsor's Statement

Wall DLa was a prefabricated, demountable

wood-frame construction having braces between the studs, an outside face of plywood and

insulating board siding, and an inside fare of plywood wallboard.

The price of this construction in Washington,

D. C, as of July 1937 was $0.58/ft2.

(a) Description

The 8-ft wall specimens, shown in figure 21, were 8 ft 4% in. high, 8 ft 11 in. wide, and 5% in. thick. The frame was similar to the frame for the 8-ft specimens, wall DL, except that at the

edges there were corner studs, AD (not studs

A), and there were diagonal braces, AE, between the studs, fastened by lag screws and

bolts. The outside face and the inside face were like those for the 8-ft specimen, wall DL,

except that there was a corner wallboard panel

at each edge (not an edge panel Iji in. wide)

and a corner molding vertically along the outer

edge of each corner wallboard panel, attached

by spring-steel clips.

Corner studs.—The corner studs, AD, shown

in figure 22, were like studs A except that the

boards were 1 in. (not in.) thick and that a southern-pine strip, AF (not blocks J), 1% by

2% in. (nominal 2 by 3 in.), 8 ft 4% in. long, flush with the inside edge of the boards, was fastened

to each board by 8d casing nails, spaced about

6% in., extending through the boards into the

strip. Each end of the strip extended 2 % m. beyond the boards and was tenoned 1% by lYs in. There were no grooves in the inner surface

of the boards.

A channel 1% by % in. deep along the center

line of one board (outside face of stud) provided space for siding clips. There were five holes, M-in. diam, at midwidth of each msidc

face of the stud. The distances of the holes

from the lower end of the stud were 2% ui., 1 ft 1^6 in., 3 ft 1P%6 in., 6 ft 10%^ m., and 7 ft 8%

in. The holes were for lag screws to fasten

stud rails and braces. A groove (saw kerf),

Kb by %2 in. deep, in each inside face, % in. from

the inside edge of the stud, received the clips for attaclung the corner molding.

19
The corner studs were covered with one coat

of wliite exterior primer, applied with a brush.

A sheet-steel bearing plate, AG, No. 12 U. S. Standard Gage (0.1072 in), on each end of the

stud was fastened by one 5d casing nail in each

board and one in the strip.

There was a corner stud rail, AH, like stud

rail A^, except that it was across both outside

faces of the corner stud. Because the floor plate extended beyond the corner stud, one face

of the stud rail was cut flush with the end of the

stud. The stud rail was attached to each inside

face of the stud, by three stud-rail clips and

wedges, like those for stud A. The stud- rail clips hooked over 2-in. lag screws, not pins as

ui wall DL.

Figure 21.

Eight-foot ivoll specimen DLa.

A, stud; B. floor plate; C, top plate; D, siding: /'. wallboard panels; AD, corner stud; AE. brace.

20
Four steel bracket clips, AI, along the inside The steel ])arts, except the lag screws, w ei e edge of the stud, each consisting of a spring- covered with one coat of black metal primer,

steel clip. No. 20 U. S. Standard Gage (0.0368 applied by dipping.

in), were fastened to a sheet-steel bracket, No. The corner studs were fastened to the flooi' 18 U. S. Standard Gage (0.0490 in), by a }8-in. plate and top plate by one hook l)oll at each

steel rivet. No. 10 B & S Gage (0.1019 in). The end which hooked over a lag screw, not by two

bracket clips Avere spaced approximately 7 in., hook bolts over a pin, as in stud A.

2 ft 11/8 in., 5 ft 3}i in., and 7 ft 7% in. from the Corner wallhoard -panels. —The corner waillower end of the stud and were fastened by one board panels wei'e the same as a full-width

edge, projecting into the groove, and by two 6d panel, F, cut to a face width of 1 ft 5}^ in. casing nails extending into the board. They Diagonal braces. —The diagonal braces, AE,

wa're for attaching the corner molding, AJ, and were sheet steel. No. 14 U. S. Standard Gage

for supporting the corner wallboard panels. (0.0766 in), and were arranged in the specimens

Figure 22.

Details of wall DLa.

F, wall board panel; AD, corner stud; AF, strip; AE, brace; AG, bearing plate; .ill, corner stud rail; AI. bracket clip; AJ. corner molding.

[21]
as slioAV7i in figiire 2 1 . Tb e braces were fastened

to each corner stud by a Ys-m. square washer

and a 3-in. lag screw in the holes 1 ft 1%6 in. and 6 ft lO/ie in. from the lower end of the stud

and by a %-in. square washer and a 2-in. lag- screw in the hole at midheight. Each brace was fastened to an intermediate stud by a %-m. machine bolt, 4 in. long, with a %-'m. square washer under the head and under the

]mt.

(6) Comments

In a house there is a corner stud at each corner which is part of the two intersecting walls. In

each wall for two stud spacings (40 in.) from

the corner stud, braces between the studs pro- vide resistance to racking loads. The 8-ft specimens DLa, therefore, represented a wall

consisting of two braced walls connected by an

luibraced wall.

2. Racking Load

Wall specimen DLa-R3 is shown uiider racking load in figure 23. The results of the racking load on specimens

DLa-Rl, R2, and R3 are shown in table 9 and

figure 24. Under a load of 0.200 kip/ft on specimen

DLa-Rl and of 0.275 kip/ft on specimens R£

and R3, the adjacent wallboard panels were

displaced ji in. vertically and the adjacent

pieces of siding were displaced in. horizontally. Under the maximum load on each

specimen, the vertical displacement of the

wallboard was V/i in. and the horizontal dis- placement of the siding was % in. In each

specimen the lag screws (at midheight) fastening

the braces pidled from the corner studs. In

specimen R3 the studs adjacent to the corner studs cracked.

Figure 23. —Wall sptciinen Dl.u- RS under rucl.mg load.

A, deformeter.

[22]
.45

.40 \ .35

< .30

.20

.15

.10

.05

0

/ OOl

/—o»-

o 3

/ J yop-o

1 I

Jj

u

1

0 z 6

c/eformaf/on /n./m

Figure 24.Racking load on wall DLa.

Load-deformation (open circles) and load-set (solid circles) results for specimens DLa-Rl, R2, and R3.

Racking- loads were also appliod to one spooimen similar to DLa-Rl, R2, and R3 except that

the braces were sheet steel No. 18 U. S. Standard Gage (0.0490 in), not No. 14 U. S. Standard

Gage (0.076G in). Under a load of 0.331 kip/ft

the deformation was 6.8 in. The set was 4.4 in.

VII. FLOOR DM

1. Sponsor's Statement

Floor DM was a prefabricated, demonntable

wood-frame construction having an upper face

of plywood flooring panels and a lower face of plywood ceiling panels.

The price of this construction in Washington,

D. C, as of J\ily 1937 was $0.48/ft^

(a) Description

The floor specimens, shown in figure 25, were

12 ft 9K in. long, 5 ft 0 m. wide, and in. deep. Each specimen consisted of a wood

frame to which the faces were attached. The

Figure 2b.—Floor DM.

A, joist; B, girt; C, flooring panel; X>, ceiling panel; H, I, J, boards; L, blocks.

[23]
frame was three prefabricated wood joists, A,

attached at each end to a wood girt, B, by bolts. The upper face was 17 prefabricated plywood

flooring panels, C, attached by spring-steel clips.

The lower face was 11 prefabricated plywood

ceiling panels, D, attached by spring-steel clips. Joists.—The joists, A, shown in figure 26, were prefabricated members each consisting of two southern-pine boards, E, -%2 by 7% in. (nominal 1 by 8 in.), 12 ft 6 in. long, and 14 southern-pine blocks 1% by VA in. (nominal 2 by

4 in.), 2 blocks, F, 7 in. long and 12 blocks, G, 6 ill. long.

The blocks F were in. from each end of the joist, the ends of each block being y^, in. from each edge of the boards. Each block was

fastened to each board by three 8d casing nails. The blocks G were in pairs 1% in. apart, the

pairs being centered 2 ft 1 in., 3 ft 9 in., 5 ft 5 in., 7 ft 1 in., 8 ft 9 in., and 10 ft 5 in. from the

end of the joist. The upper end of each block was % in. below the upper edge of the boards.

Each block was fastened to each board by two

8d casing nails. Twelve holes, Ke-in. diam, extended through

the boards; eight at midwidth spaced 1 ft 8 in., the end hole being 5 in. from the end of the

joist, for pins to attach flooring and ceiling, and

two at each end of the joist, each hole being

l]i in. from the end and 1 in. from the edge of the board. Fastening the girts were 12 steel pins, K (%6-in. diam, 5^ in. long), one through

each hole. One coat of white exterior primer was applied

to the joists with a brush.

Girts.—The girts, B (fig. 25), were prefabricated members, each consisting of five pieces of southern pine, by 7% in. (nominal 1 by 8 in.); one piece, H, 4 ft W^^U in. long; two pieces, /,

1 ft 6% in. long; and two pieces, J, 9%2 in. long.

The pieces / and J were each fastened to the

piece H, with a space 1% in. between adjacent

pieces, by five 6d cement-coated casing nails

through the piece H into the pieces / and J.

Figure 26.Details of floor DM.

A, joist; E, boards; F, G, blocks; A', pin; D, ceiling panel; P, plywood panel; Q, plywood strips; M, tension strap; N, spring washer; 0, flooring clip.

[24]
A southern-pine block, L, 1% by 1/s in. (nominal 2 by 2 in.), 7 in. long, was centered in each space and fastened by two 6d cementcoated casing nails through the girt into the

block.

There were two holes, /{e-in. diam, at midwddth of each girt, adjacent to each block.

The girts were covered with one coat of white

exterior primer, applied with a brush.

Each joist was attached to each girt by two

%-in. square-head machine bolts, 6 in. long.

Each bolt, with a %-in. round washer under the

head, extended through one of the holes in the

girt, through a tension strap (over the pins in the end of the joist), and through a spring

washer and was secured by a square nut. The tension straps, M (fig. 26), were sheet

steel. No. 11 U. S. Standard Gage (0.1225 in.). The spring washers. A', were spring steel. No.

13 U. S. Standard Gage (0.0919 in.). The tension straps and spring washers were

covered with one coat of black metal primer,

applied by dipping.

Flooring panels.—The flooring panels, C (fig. 25), were Duali-faced Douglas fir plywood % in. thick, prefabricated into panels 1 ft 8 in. wide.

The panels were in lengths of 10 in., 2 ft 6 in., and 5 ft 0 in. There was a groove (saw kerf)

/i6 by % in. deep (at midthickness) and a rabbet

% in. by Ke in. deep (below the groove) along

each edge and each end of each panel. The

groove was for alining adjacent panels, and the

rabbet was to provide close contact between the

upper surfaces of the panels.

A 45° bevel Ke in. deep extended along each

edge and each end of the upper surface. The upper and lower surfaces of the panels were covered with one coat of stain, applied

with a brush, and the upper surface was waxed.

The flooring panels were in alternate rows and were attached to the joists by spring-steel

flooring chps, 0 (fig. 26), No. 20 U. S. Standard

Gage (0.0368 in). Each panel was attached

along one edge by a flooring clip at each joist

(between the boards) which hooked over the

pin through the joist and extended into the

gToove in the panel.

The butted edges and ends of the panels were

alined by galvanized sheet-steel splines. No.

16 U. S. Standard Gage (0.0613 in), % in. wide,

1 ft 6)2 in. long, ui the grooves over and between

the joists and 9/4 in. long in the grooves over- hanging the joists.

Ceiling panels.—The ceiling panels, D (fig. 26), were prefabricated members 1 ft 8 in. wide

and were in two lengths, 5 ft 0 in. and 2 ft 6 in.

;

each consisting of a plywood panel, P, backed

by plywood strips, Q, 2% in. wide. The plywood was Douglas fir plywood, interior type,

% in. thick.

A rabbet % by K in. extended along each edge on opposite surfaces to join the panels and a 45°

bevel /i in. deep along each edge of the lower

surface. In each 5 ft 0 in. panel there were five strips,

Q, two of which were 5 ft 0 in. long and thiee 1 ft 3K in. long. The 5-ft 0-in. strips were fas- tened by glue and by %-in. wire brads, spaced

about 6 in., along each edge of the upper sui'face, flush with the outer edge of the bevel. The 1-ft

3K-iii- strips were fastened along each end of the panel on the upper surface flush with the

end, and at midlength.

The 2-ft 6-in. panels were like the 5-ft 0-in. panels except that the rabbet extended along

the butted end (on opposite surfaces of adjacent

panels) and the bevel along the butted end on

the lower surface of each panel. There was no

strip Q 1 ft SYz in. long at midlength.

The lower surface of each panel was treated

with one coat of wood filler and covered with

one coat of white interior primer and one coat

of white interior wall pamt, applied with a

brush.

The ceiling was in alternate rows of 2-ft 6-in. and 5-ft 0-in. panels, attached to the joists by

flooring clips. One edge of each panel ex- tended into the rabbet of the adjacent panel.

The other edge was attached to each joist by a

flooring clip (outside the boards) which hooked

over the pin through the joist and over the projecting edge of the plywood strip.

(b) Comments

Floors are assembled on the building site from standardized prefabricated parts which are demountable. The joist spacing is 20 in., and

the width of the floor is any mifltiple of this spacing.

Flooring and ceiling are available in panels

20 in. wide, 40 in. long.

[25]
In buildings having no basement, rock-wool

insulation usually is placed between the first- floor joists, supported by fiberboard attached

to the joists by spring-steel clips.

2. Transverse Load

The results of the transverse load on floor specimens DM-Tl , T2, and T3 are given in

table 11 and figure 27. The speed of the movable head of the testing

machine was adjusted to 0.172 in./min.

The transverse joints in the ceiling on speciTable 11.

Structural properties of floor DM

[Weight, based on face area; 6.93 lb/ft 2]

Transverse load; span,

12 ft 0 in.

Concentrated load; diam of steel disk,

1 in.

Impact load; weight

of sandbag, 80 lb

Specimen

Maxi- mum

load Specimen

Maxi- mum

load Specimen

Ma.Ki- mum

height

of drop

Tl Win 2 258. 3 161.6

230.0

PI

lb

"1, 000

»1. 000

al, 000

n

ft 10

10

10 P«PS

12 TS. 73

Average.-- - 216.6 Average 1,000 Average 10

Specimen undamaged. Test discontinued.

men Tl opened about ji in. under a load of 225

lb/ft" and one board in an outer joist I'uptured

under a loading roller. Under the maximum

load all the joists ruptru'ed and one flooring

clip pulled through a ceiling panel.

Under a load of 110 lb/ft- on specmien a board in one outer joist ruptured under a loading roller. At a load of 150 Ib/ft^, the trans- verse jomts in the ceiling were open about in. The other outer joist ruptured near midspan

under a load of 153 Ib/ft^. Under the maximum

load, the middle joist ruptured under a loading roller. Under a load of 120 lb/ft- on specimen TS, one board in an outer joist cracked at a knot

outside a loading roller, and under a load of

130 Ib/ft^ the joist ruptured. Under the maximum load, the middle joist buckled laterally.

3. Concentrated Load

The results of the concentrated load on speci- mens DM-Pl, P2, and PS are given in table 11 and in figure 28. After the concentrated load had been applied,

the set in specimen DM-Pl was 0.031 in.: in

P2, 0.037 in.; and in PS, 0.028 in. No other

effects were observed.

0 0,5 W /.5 2,0

def/ecf/on in. Figure 27.—Transverse load on floor DM.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens DM-Tl, TZ, and TS on the span 12 ft 0 in.

0 0/ 0.2 /ndenfaf/or? /n. Figure 28.

Concentrated load on floor DAI.

Load-indentation (open circles) and load-set (solid circles) results for specimens DM-Pl, P2, and PS.

[26]
Figure 29. flour npicimtn l)M-ll during the impact test.

4. Impact Load

Floor specimen DM-Il during the iinpact

test is shown in fisure 29. The results for

6

V

0

m (

0

?—°

-o

•

•

CX3

CO

-CO

•

<

•

0 0.5 /.O /.5

def/ecfi'on in. Figure 30.

Impact load on floor DM.

Heii;ht of drop-deflection (open circles) and heieht of di'op-set (solid

circles) results for specimens DM-11, 12, and IS, on the span 12 ft 0 in.

specimens DM-Il, 12, and 13 are shown in table 11 and m figure 30. At a drop of 2.5 ft on specimen 12, a flooring

clip sprang free from a ceiling panel near a supporting roller. The joints in the flooring began

to open after a drop of 4.0 ft on specimens 11

and 12 and a drop of 5.0 ft on specimen 13. A clip pulled through a ceiling panel at a drop

of 6.0 ft on specimen II and 5.0 ft on specimens

12 and 13. After a drop of 8.0 ft, one or more

ceilmg panels were separated from the joists in specimen 11; after 5.5 ft, in specunen 12; and

after 10.0 ft, in specimen 13. At a drop of 8.5

ft on specimen 12, two 10-in. flooring panels

fell from the edge of the specimen.

After the 10-ft drop on each specimen, the

joists were undamaged. Most of the ceiling

and flooring panels were loose. \m. ROOF DN

1. Sponsor's Statement

Roof DN was a prefabricated, demountable

wood-frame construction having an upper face

of plywood and insulating-board roofing.

The price of this construction in Washington,

D. C, as of July 1937 was $0.39/ft-.

[27]
(o) Description

The roof specimens, shown in figure 31, were

14 ft 9% in. long, 5 ft 0 in. wide, and 1% in. deep.

Each specimen consisted of a wood frame to which the upper face was attached. The frame was three prefabricated wood rafters, A,

attached at each end to a wood header, B, by

bolts. The upper face was 13 pieces of pre- fabricated plywood and insulating-board roof- ing, C, attached by spring-steel clips. Rafters.—The rafters. A, shown in figure 32, were prefabricated members each consisting of two southern-pine boards, D, "^fa by 5 (nominal 1 by 6 in), 14 ft 6}8 in. long, and seven

southern-pine blocks, E, 1% by 3K in. (nominal

2 by 4 in), 8% in. long, the ends mitered, parallel,

37 degrees. The blocks were centered 2 ft 4%

m., 4 ft 5/8 in., 6 ft 6 in., 8 ft 6% in., 10 ft 1% in., 12 ft 8% in., and 13 ft 10)^ in. from the upper

end of the rafter; the upper surfaces of the

blocks were % in. below and parallel to the upper

edge of the boards. Each block was fastened to the boards by three 8d casing nails through each

board into the block.

There were 19 holes, /(e-m. diam, through

each board; 4, F, for fastening the headers, 1, G, for fastening the rafter at the eave, 2, H, for fastening the rafter at the ridge, and 12, /, for fastening studs for attic partitions.

In these specimens the holes G, H, and / were

not used. The holes F were 1% in. from the

ends and !%& in. from the edges of the boards.

The hole G was 5% in. from the end and 1% in. from the upper edge of the boards. Of the holes

H, the upper one was 3% in. from the end and 1%

in. from the upper edge of the boards. The center line of the holes forms an angle of 53° with

the edge of the boards, and the spacing of the

holes was IK in. The holes / were in pairs adjacent to the upper six blocks. The center line of the holes was ^Ke in. from the block, and the

holes were 1% in. from the edges of the board.

The rafters were covered with one coat of white exterior primer, applied with a brush.

There were 13 sheet-steel rafter straps, J, No.

16 U. S. Standard Gage (0.0613 in), across the

upper edge of each rafter, spaced 1 ft 0 Ke in. on

centers, the upper strap being 1 ft 3% in. from

Figure SI.—Roof DN.

A, rafter; B. hoador; C, roofing.

[28]
the upper end of the rafter. Each rafter strap was fastened by one 6d cement-coated cashig

nail m the edge and one 2d galvanized roofing

naU in the side of each board . The straps were

for attaching the roofing.

The rafter straps were covered with one coat

of black metal primer, applied by dipping.

Headers.—The headers, B (fig. 31), were pre- fabricated members, each consisting of a southern-pine board, 1% by bji in. (nominal 2 by

6 in), 4 ft 11% in. long, and three southern-pine

blocks, 1^^ by 3^ hi. (nominal 2 by 4 m), 5% in. long. The blocks were centered Q^Ke in., 2 ft

5^?^6 in., and 4 ft in. from the end of the

board and were each fastened by three lOd

common naUs through the board into the

block. Two holes, /ie-in. diam, were at midwidth of each block, one 1%6 in. from each end

of the block.

The headers were covered with one coat of white exterior primer, applied with a brush.

Each rafter was attached to each header by

Figure 32.—D,

^.rafter; D, boards; K, blocks; i\ G, H 1; holes; J. rafter strap; C, roofing;

two %-hi. square-head machine bolts, 4 hi. long.

The bolts, with a Ys-in. round washer under the

head, extended through the holes in the rafter and in the header and were fastened by a %-in

round washer and a square nut. Roofing.—The roofing pieces, C (fig. 32), were

prefabricated members 1 ft 6 in. by 5 ft 0 in. Each piece had an outside face, K, of plywood

and an inside face of insulating board, L. The outside face, K, of each piece was two

strips of Douglas fir pljrw^ood, exterior type,

% in. thick, 1 ft 1% in. and 3 ft 10}^ in. long, the

ends butted. A groove (saw kerf) Ke by Yie in. deep extended along the butted end of each

strip. The butted ends were aimed by a galvanized sheet-steel spline. No. 16 U. S. Standard Gage (0.0613 m), % by 1 ft 5% m., m the

grooves. The inside face, L, was insulating

board Iji in. thick, lOy. in. by 5 ft 0 in. long,

fastened to the plywood, the upper edges flush,

by glue.

A southern-pine clip rail, M, 1% by 1%, in.

lails of roof DN.

K. outside face; L, inside face; AI, clip rail; N, rubber strip; X, siding clip.

[29]
(nominal 2 by 2 in), 5 ft 0 in. long, along the

lower edge of the insulating board was fastened

to the plywood by glue and by 4d galvanized

roofing nails, spaced about 7}^ in. and extended

through the plywood into the clip rail. A

sponge-rubber strip, A^^, M in. thick and % in. wide, was fastened to the lower sin-face of the

clip rail by glue and by %-in. basket nails, spaced

about 7V2 in. This strip was for closing any air gap between overlapping pieces of roofing.

The outside surface of the roofing was covered

with one coat of white exterior primer and one

coat of green roof paint, applied with a brush.

There were three spring-steel siding clips, X,

on each roofing piece along the lower edge of the

clip rail. The clips were centered 10 in., 30 in., and 50 in. from the end of the clip rail and were

each fastened by two %-in. round-head wood

screws. The roofing was attached to the rafters by

the siding clips, which extended over the rafter

straps.

(b) Comments

The roofs are assenrbled on the building site from standardized prefabricated parts which

are demountable. The roof has a pitch of 37°

and the rafter spacing is 20 in. The width of the roof is any midtiple of this spacing.

The roofing is available in lengths which are multiples of 20 in. up to 80 in.

2. Transverse Load

The results for the transverse loads on roof

specimens DN-Tl, T2, and T3 are given in table 12 and in figure 33. The speed of the movable head of the testingmachine was adjusted to 0.328 in./min.

Table 12.

Structural -properties of roofs DN and DO

[ \Veit':ht, based on face area; DN, 5.36 lb/ft DO, 5.97 lb/ft?]

60

Construction symbol

Average.

DO.

Average.

Transverse load; span,

14 ft 0 in.

Specimen Maxi- mum

load

Iblff 73.7

52.0 52.0

59.2

147.1 162.9

135.7

Concentrated load; diam

of steel disk, 1 in.

Specimen

PI. P2_

Pl.

P2. PS.

IVIaxi- mum

load

lb

1, 000 837

1.000

946

924

950

40

^ 20

0

o 1

\ -\

0

'-^

o

-o-^>—o

0/23 DN

def/ecfion in. Figure 33.—Transverse load on roof DN.

Load-doUcction (open circles) and load-set (solid circles) results for speci- mens DN-Tl, T2, and TS on the span 12 ft 0 in.

In specimen Tl, under a load of 31.7 Ib/ft^ the

middle rafter cracked at a knot imder a loading

roller. Under a load of 38.0 lb/ft', one outer

rafter cracked at a knot near midspan and ruptured under a load of 60.7 Ib/ft^ Under the

maximum load, all the rafters ruptured.

In specimen T2, jone outer rafter cracked at a knot near midspan under a load of 24.3 Ib/ft^ and ruptured under a load of 45.0 lb/ft'. The

middle rafter ruptured at midspan under a load

of 48.6 Ib/ft^

Under a load of 40.0 lb/ft" on specimen TS, one board in an outer rafter cracked at a knot

near midspan and the other board ruptured at knots under the loading rollers. Under the

maximum load, the middle rafter ruptured

under both loading rollei-s.

3. Concentrated Load

The results of the concentrated loads on

specimens DN-Pl, P2, and PS are shown in table 12 and in figure 34. The concentrated loads were applied to the

roofing midway between two rafters and 10 in. from the exposed edge of the plywood. Under

the maximxim load on specimen P2, the disk

pimched through the plywood roofing. Under

[30]
mo

I

o

ZOO

—O— o

/ 6^—

0

i

i

o5

y

1

1

1m—

'

L -

i

0./ 0.^ inden/of/on

0.5

/'n. Figure 34.

-Concentrated load on roof DN.

Load-indentation (open circles) and load-set (solid circles) results for specimens DN-Pl, Pi. and P3.

the maximum load on specimens PI and PS,

the plywood cracked along the grain near the

disk.

IX. ROOF DO

1. Sponsor's Statement

Roof DO was a prefabricated, demountable

wood-frame construction having an upper face

of plywood and insidating-board roofing. It was similar to roof DN except for rafter depth.

The price of this construction in Washington,

D. C, as of July 1937 was $0.39/fV.

(a) Description

The roof specimens were 14 ft 9% in. long,

5 ft 0 in. wide, and 9^^ in. deep. Each specimen

consisted of a wood frame to which the upper

face was attached.

Roof DO was like roof DN except that the

frame was 7% in. deep instead of 5% in. The

frame was three prefabricated wood rafters,

attached at each end to a wood header by bolts. Rafters.—The rafters were like rafters A in roof Z>iV except that the boards were 7% in. wide

and the blocks were 11 in. long.

Headers.—The headers were like headers B

in roof DN except that the boards were 7% in. wide and the blocks were 7% in. long. In all other respects the roofs were similar.

(b) Comments

Roofs DO are similar to roofs DN having an

8-in. rafter to increase the transverse strength

when required by the length of span.

2. Transverse Load

Roof specimen D0-T2 under transverse load

is shown in figure 35. The results for speci-

\ \

Figure 35.

Roof specimen D0-T2 during the transverse test.

[ 31 ]
/20

/OO

I

60

^ 40

20

0

\ m

O-H

o Y c

3

f-- m o d o

•

•

• r 0/2 DO

def/ec//on /n. Figure 36.—Transverse load on roof DO.

Load-deflection (open circles) and load-set (solid circles) results for speci- mens DO-ri, TS, and TS. mens DO-Tl, T2, and T3 are given in table 12 and in figure 36. The speed of the movable head of the testing

machine was adjusted to 0.235 in./min.

One outer rafter in specimen Tl cracked at a knot near midspan imder a load of 71.4 lb/ft". Under a load of 120 Ib/ft^, the other outer

rafter cracked at a knot near a loading roller. The middle rafter cracked under a load of 141

Ib/ft^. Under the maximum load, one outer

rafter ruptured.

In specimen T2 under a load of 67.1 Ib/ft^, cracks appeared at a knot near midspan in an

outer rafter. Under a load of 117 lb/ft', ii crack occiu-red at midspan in the middle rafter. Under the maximum load, all the rafters ruptured.

In specimen TS under a load of 68.0 lb/ft ^ a crack appeared at a knot in both the middle

and one outer rafter. The other outer rafter

cracked near midspan under a load of 103

Ib/ft^ Under the maximum load, each rafter ruptiu'ed.

3. CONCENTR.ITED LoAD

The results of the concentrated loads on roof

specimens DO-Pl, P2, and PS are shown in table 12 and in figure 37.

300

<o

600

400

200*

0

#

0 ( )

1

I

Iu

FT

0 0.2 0.4 0,6

/nc/enfaf/on /n. Figure 37.

Concentrated load on roof DO.

Load-indentation (open circles) and load-set (solid circles) results for specimens DO-PI. P2, and PS. The concentrated loads were applied to the

roofing midway between two rafters and 10 in. from the exposed edge of the plywood. Under

a load of 750 lb on specimen P2, the plywood

cracked along the grain adjacent to the disk.

Under the maximum load on each specimen,

the (hsk punched through the plywood.

X. ADDITIONAL COMMENTS BY

SPONSOR

"PHC" houses are assembled from prefabricated parts which are made in a specially

equipped factory. A house is assembled in

11 bout one week. Many different arrangements

of the rooms and architectural efiects are

possible.

Because the parts are readily demountable,

a small house can easily be enlarged at any time

by removing a portion of the building and

assembling the desired extension from both old

and new parts.

Horizontal dimensions of this construction

are multiples of 20 in., and the ceiling height is 8 ft. Because there is no sheathing, diagonal

braces between the studs are necessary. Twelve experunental houses have been erected

and dismantled in the southeastern part of New

York State. The foundations were masonry,

132]
usually concrete block, with a 2- by 8-in. wood

siU anchored by }2-in. bolts. Partitions were

similar to walls except that there were no stud

rails and both faces were waUboard panels.

Ceiling panels were either plywood or insulating board.

Details of a two-story house assembly are

shoAVTi in figure 38.

First floor joists rest on 1- hj 6-tn. blocks,

6 in. long, on the sill. Joists of other floors rest on studs of walls and partitions below.

Tenons of studs in outside walls at right angles

to joists are seated in mortises formed by joists

and girts. Tenons of studs in load-bearing

partitions are seated in mortises formed by

butting joists. Attachments are a sheet-steel

tension strap on each side of the joist fastened

by a bolt and spring-steel washer. This type

of fastening takes up the shrinkage in the wood

parts.

Tenons of studs in partitions and outside

outside walls parallel to joists are seated in
mortises in the joists and are fastened by steel pins through the joist and tenon. Lower ends of rafters rest on ceihng joists,

the end block of the rafter butting the end

block of the joist. Attachments are sheet-steel

tension straps.

Upper ends of rafters are attached to ridge

assembly. Splice blocks, notched into the ridge

piece, extend between the boards of the rafters and are fastened by steel pins through the

boards and the block. The ridge is covered

by a roofing ridge piece attached by a springsteel strap.

The physical properties of the insulatingboard were determined by C. G. Weber, of the

Paper Section of this Bureau, under the siipervision of B. W. Scribner.

The descriptions and drawings wei'e prepared

by E. J. Schell and G. W. Shaw, of the Building

Practices and Specifications Section, imder

the supervision of V. B. Phelan.

The structural properties were determined

by the Engineering Mechanics Section, under

the supervision of H. L. Whittemore and M. F. Peck, with the assistance of the following members of the professional staft'; E. S. Cohen, A.

H. Easton, W. G. Hoback, J. S. Rimmer, L. R.

Sweetman, and H. L. Weiss.

Washington, June 1, 1942.

o

[ 34]
9 BUILDING MATERIALS AND STRUCTURES REPORTS

[Continued from cover page ii]

BMS33 Plastic Calking Materials 10^ BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 10^ BMS35 Stability of Sheathing Papers as Determined by Accelerated Aging 10^ BMS36 Structural Properties of Wood-Frame Wall, Partition, Floor, and Roof Constructions

with "Red Stripe" Lath Sponsored by the Weston Paper and Manufacturing Co-_- 10(4 BMS37 Structural Properties of "Palisade Homes" Constructions for Walls, Partitions, and

Floors Sponsored by Palisade Homes 10^ BMS38 Structural Properties of Two "Dunstone" Wall Constructions Sponsored by the W. E. Dunn Manufacturing Co lOji BMS39 Structural Properties of a Wall Construction of "Pfeifer Units" Sponsored by the Wisconsin Units Co 10f5 BMS40 Structural Properties of a Wall Construction of "Knap Concrete Wall Units" Sponsored

by Knap America Inc 10^ BMS41 Efifect of Heating and Cooling on the Permeability of Masonry Walls 10^ BMS42 Structural Properties of Wood-Frame Wall and Partition Constructions with "Celotex"

Insulating Boards Sponsored by the Celotex Corporation 15^ BMS43 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 2 10^ BMS44 Surface Treatment of Steel Prior to Painting 10^ BMS45 Air Infiltration Through Windows 10^ BMS46 Structural Properties of "Scot-Bilt" Prefabricated Sheet-Steel Constructions for Walls,

Floors, and Roofs Sponsored by the Globe-Wernicke Co 10(4 BMS47 Structural Properties of Prefabricated Wood-Frame Constructions for Walls, Partitions, and Floors Sponsored by American Houses, Inc 10(4 BMS48 Structural Properties of "Precision-Built" Frame WaU and Partition Constructions

Sponsored by the Homasote Co 10^ BMS49 Metallic Roofing for Low-Cost House Construction 10^ BMS50 Stability of Fiber Building Boards as Determined by Accelerated Aging 10^ BMS51 Structural Properties of "Tilecrete Type A" Floor Construction Sponsored by the

Tilecrete Co lOi BMS52 Effect of Ceiling Insulation upon Summer Comfort 10^ BMS53 Structural Properties of a Masonry Wall Construction of "Munlock Dry Wall Brick"

Sponsored by the Munlock Engineering Co 10^ BMS54 Effect of Soot on the Rating of an Oil-Fired Heating Boiler 10^ BMS55 Effects of Wetting and Drying on the Permeability of Masonry Walls 10^ BMS56 A Survey of Humidities in Residences 10^ BMS57 Roofing in the United States—Results of a Questionnaire lO^S BMS58 Strength of Soft-Soldered Joints in Copper Tubing 10^ BMS59 Properties of Adhesives for Floor Coverings 10^ B MS60 Strength, Absorption, and Resistance to Laboratory Freezing and Thawing of Building

Bricks Produced in the United States 15^ BMS61 Structural Properties of Two Nonreinforced Monolithic Concrete Wall Constructions. _ lOfS BMS62 Structural Properties of a Precast Joist Concrete Floor Construction Sponsored by the Portland Cement Association 10^ BMS63 Moisture Condensation in Building Walls 10^ BMS64 Solar Heating of Various Surfaces 10^ BMS65 Methods of Estimating Loads in Plumbing Systems lOi BMS66 Plumbing Manual 20^ BMS67 Structural Properties of "Mu-Steel" Prefabricated Sheet-Steel Constructions for Walls,

Partitions, Floors, and Roofs Sponsored by Herman A. Mugler 15(4 BMS68 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 3 150 BMS69 Stability of Fiber Sheathing Boards as Determined by Accelerated Aging 10^ BMS70 Asphalt-Prepared Roll Roofings and Shingles 15^ BMS71 Fire Tests of Wood- and Metal-Framed Partitions 20^ BMS72 Structural Properties of "Precision-Built, Jr." Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co 106 BMS73 Indentation Characteristics of Floor Coverings 10(4 BMS74 Structural and Heat-Transfer Properties of "U. S. S. Panelbilt" Prefabricated Sheet-Steel Constructions for Walls, Partitions, and Roofs Sponsored by the Tennessee Coal, Iron & Railroad Co 15(4 BMS75 Survey of Roofing Materials in the North Central States 15(4 BMS76 Effect of Outdoor Exposure on the Water Permeability of Masonry Walls 15^ BMS77 Properties and Performance of Fiber Tile Boards 10^ BMS78 Structural, Heat-Transfer, and Water-Permeability Properties of Five Earth-WaU Constructions 20(4 BMS79 Water-Distributing Systems for Buildings 15^ BMS80 Performance Test of iPloor Coverings for Use in Low-Cost Housing: Part 4 15<4 BMS81 Field Inspectors' Check List for Building Construction (cloth cover; size, 5 by 7)i inches) _ 20^ BMS82 Water Permeability of Walls Built of Masonry Units 20^ BMS83 Strength of Sleeve Joints in Copper Tubing Made with Various Lead-Base Solders 10^ BMS84 Survey of Roofing Materials in the South Central States 15^

[List continued on cover page iv]
BUILDING MATERIALS AND STRUCTURES REPORTS

[ Continued from cover page in ] BMS85 Dimensional Changes of Floor Coverings With Changes in Relative Humidity and Temperature lOji BMS86 Structural, Heat-Transfer, and Water-Permeability Properties of "Speedbrik" Wall

Construction Sponsored by the General Shale Products Corporation ISji BMS87 A Method for Developing Specifications for Building Construction 10^ BMS89 Structural Properties of "Precision-Built, Jr." (Second Construction) Prefabricated Wood-Frame Wall Construction Sponsored by the Homasote Co 15^ BMS90 Structural Properties of "PHC" Prefabricated Wood-Frame Constructions for Walls,

Floors, and Roofs Sponsored by the PHC Housing Corporation 15^