bureau - - ouaadardd
The prograni of research on building materials and structures, carried on by the

National Bureau of Standards, was undertaken with the assistance of the Central Housing Committee, an informal organization of Government agencies concerned with

housing construction and finance, which is cooperating in the investigations through a subcommittee of principal technical assistants.

CENTRAL HOUSING COMMITTEE

SUBCOMMITTEE ON TECHNICAL RESEARCH

Walter Junge, Chairman. A. C. Shire, Vice Chairman.

Federal Housing Administration. United States Housmg Authority.

Sterling R. March, Secretary.

Albert G. Bear,

Veterans' Administration.

Pierre Blouke,

Federal Home Loan Bank Board (Federal Loan Agency).

Carroll W. Chamberlain,

Public Buildings Administration (Federal Works Agency).

Joseph M. DallaValle,

Public Health Service (Federal Security

Agency).

John Donovan,

Farm Security Admiaistration (Agriculture).

George E. Knox,

Yards and Docks (Navy).

Vincent B. Phelan,

National Bureau of Standards (Commerce).

Edward A. Poynton,

Office of Indian Affairs (Interior).

George W. Trayer,

Forest Service (Agriculture).

Elsmere J. Walters,

Construction Division (War).

CHAIRMAN OF SECTIONS

Specifications Materials Maintenance

Carroll W. Chamberlain Elsmere J. Walters John H. Schaefer

Mechanical Equipment Methods and Practices

Robert K. Thulman

NATIONAL BUREAU OF STANDARDS

STAFF COMMITTEE ON ADMINISTRATION AND COORDINATION

Hugh L. Dryden, Chairman.

Mechanics and Sound.

Phaon H. Bates, Gustav E. F. Lundell,

Clay and Silicate Products. Chemistry.

Hobart C. Dickinson, Addams S. McAllister,

Heat and Power. Codes and Specifications.

Warren E. Emley. Henry S. Rawdon,

Organic and Fibrous Materials. Metallurgy.

The Forest Products Laboratory of the United States Department of Agriculture is cooperating with both committees on investigations of wood constructions.

[For list of BMS publications and how to purchase, see cover page III.]
DEPARTMENT OF COMMERCE • Harry L. Hopkins, Secretary

BUREAU OF STANDARDS • Lyman J. Briggs, Director

BUILDING MATERIALS

and STRUCTURES

REPORT BMS34

Performance Test of Floor Coverings for Use

in Low-Cost Housing: Part 1

by PERCY A. SIGLER a?td ELMER A. KOERNER

ISSUED JANUARY 15, 1940

Ij UNITED STATES

NATIONAL

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 ot reports are to be construed accordingly.

UNITED STATES GOVERNMENT PRINTING OFFICE • WASHINGTON • I94O

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

In connection with the research program on building materials suitable for low-cost

house construction being conducted by the National Bureau of Standards, performance

tests are being made on various floor coverings and methods of installation in order to determine their relative ability to withstand severe service. It is abusive treatment

which causes most installations of floor coverings to become prematurely unserviceable.

This report presents the results of tests on 40 different installations in the Bureau's

floor-testing chamber The condition of these installations at the end of the test is discussed, and representative photographs are shown.

A performance test on additional floor coverings and adhesives is in progress.

Lyman J. Briggs, Director.

[n]
Performance Test of Floor Coverings for Use in

Low-Cost Housing: Part 1

by Percy A. Sigler and Elmer A. Koerner

CONTENTS

Page

Foreword n

I. Introduction 1 II. Floor-testing chamber and equipment 1 III. Test conditions and procedure 3

Page IV. Description of test installations 4

V. Results _ 4 VI. Comments .

\'.\ VII. Selected references 14

ABSTRACT

A performance test was conducted in the floor- testing chamber of the National Bureau of Standards

on 40 different test installations involving 12 floor coverings and 11 adhesives. The floor coverings tested included several kinds of linoleum, felt-base floor coverings having various wearing surfaces, pressed

fiberboard, and three strip-wood floors. The bonding

agents used included lignin pastes, various resinous cements, casein-latex cement, asphaltic cements, and

nails. Installations on both a concrete subfloor and

a wood subfloor were tested. Descriptions of the

testing equipment and test installations are given. Results showing the relative magnitude of the depressions in the floor coverings caused by the testing

equipment are summarized and presented in tables. The appearance of the various installations after 48,000

cycles of the testing equipment is discussed and representative photographs are shown.

I. INTRODUCTION

The available information and literature on

the relative performance in service of different

floor coverings and various methods of instal- lation are somewhat limited, especially on the more recently developed materials and methods. Variations in such important factors as the quality of materials used, type and condition of the subfloor, the use of imderlays, the

method of installation and adhesive used, the

extent and nature of maintenance, and the

nature of exposure and abuses to which the

floor covering is subjected make direct comparisons in service difficult. In an effort to determine within a comparatively short time the relative ability of various

types of floor coverings and various methods

of installation to withstand severe and prolonged service, a performance test, necessarily

somewhat severe, was conducted in the floor- testing chamber of the National Bm-eau of

Standards. In this performance test it was

not found possible to include all factors afl^ect- ing performance in service. The efl'ects of

finishing coats, maintenance, age, and temperature were not adequately covered. The test- ing equipment was a modification of that

previously used in connection with an investigation of industrial-type floors for tlie Procurement Division of the Treasury Department [1].' The floor coverings and adhesives selected for

test were those which might be suitable for low-cost house construction [2] . The materials

tested represented good-quality merchandise

in their respective fields. The generous cooperation of various manufacturers in fiu'nishing

materials for test is acknowledged.

Laboratory investigations are also being

conducted on the various floor coverings and

adhesives to determine their relative merits

with respect to pertinent properties [3,4].

II. FLOOR-TESTING CHAMBER AND

EQUIPMENT

The floor-testing chamber contains a concrete circular track 4 ft wide, 8/2 in. thick, and

1 Figures in brackets indicate the literature references at the end of

this paper.

185619° -40 [1]
Figure 1

.

Performance-testing

equipment.

approximately 40 ft in cliam, with a metalshod concrete cm-b on each side. The

circular track is divided into 20 test spaces by

metal thresholds, the surfaces of which are 4

in. above the structural slab. In these test spaces wood or concrete subfioors and the vari- ous floor coverings and adhesives were installed

for test. Each test space, 4 ft wide, 6 ft long,

and 4 in. deep, was divided in half and a differ- ent installation made in each half. Figures 1 and 2 show the testing equipment

employed in this performance test. The equipment consisted of a platform truck, A, equipped

with two steel wheels 12 in. in diam and

3 in. wide. The outer wheel carried a load of

approximately 600 lb, and the inner wheel, B,

a load of approximately 500 lb. On the front

of the truck, as shown in figure 2, were mounted

two lever mechanisms, C. A swivel steel- wheel caster, E, 2 in. in diam and % in. wide, was attached to one of the levers and exerted a

force of 20 lb normal to the track. A steel-ball caster, F, 1 in. in diam, was attached to the

other lever and exerted a force of 10 lb normal

to the track. Helical springs, D, were used for applying a load on the casters. The equipment was propelled aroimd the

track at a speed of approximately 2 miles per

hr by a wheel, G (fig. 1), 4 ft in diam, which

carried a load of approximately 275 lb. The

wheel was shod with eight wooden blocks, H,

6 by 13 by Iji in., which were covered with a

cusliioning layer of rubber }i in. thick and a wearing surface of leather in. thick. This

[2]
amuigement produced a bumpiiig and slipping

action between the wheel and the test floors and imitated, to some extent, a walking action.

The average slippage of the "walking wheel"

during the test was approximately 1 percent.

The source of power was from an overhead

trolley, /, to a 1-hp electric motor, J, which

rotated the walldng wheel, G, through a reduction gear, K, and a chain drive, L. The equipment was guided around the circular track by

placing the beams, M, connecting the walking

wheel to the truck at the proper angle and also by rollers, N (fig. 2), attached to the four cor- ners of the truck and bearing against the metalshod curbs, 0. The number of revolutions of the walking wheel was recorded by a comiter attached to the frame of the equipment. The

number of cycles around the track made by the

testing equipment was recorded by a counter

mounted on a post at the side of the track and

operated by an arm attached to the truck.

A dial depth gage, R (fig. 2), was used to measure the depth of the depressions caused by

the testing equipment. The depth gage had a span of 8 in. and was equipped with a flat- ended foot )i in. in diam and a dial graduated

in thousandths of an mch. The foot exerted a pressure of 20 Ib/in^.

111. TE.ST CONDITIONS AND

PROCEDURE

Tlie concrete subfioors were poui'cd August

10, 1937, and given a steel-trowel liriisli. The

concrete was mixed fairly dry and consisted of

1 part of cement, 3 parts of sand, and 4 parts

of gravel. The wood subfloors wore bliudnailed to four wooden sleejiors which wci'c spaced 12 in. on centers and end)eddcd in concrete in the direction of travel of tlie testing

equipment. The wood subfloors consisted of

tongued-and-grooved strip flooring, ^^^2 in. thick, of either flat-grained yellow pine or edgegrained Douglas fir. The floor coverings and adhesives were in- stalled during December 1937, and thus sufficient time was allowed for the concrete subfloors to dry. The atmospheric conditions in

the testing chamber during the installations

ranged from 60- to 70-percent relative humidity

and from 50° to 60° F in temperature. A

higher temperature during installation is desirable for most types of floor coverings and is essential for a few types, such as asphalt tile. The test installations were rolled with a 150-

Ib steel roller, and a setting-up period of at

least 1 week was allowed before starting the

Figure 2.Front view of test truck and dial depth gage.

[3]
testing equipment. The test floors were swept

at least once a day during the performance test to remove loose particles.

Reference marks of white enamel were made

on the 40 installations for use in determining the

depth of the depressions caused by the equipment. Measurements of the initial depth were made on the 40 installations after 50 cycles of

the test truck. Three measurements on each

of the five paths caused by the testing equipment were taken on each installation, making a

total of 600 readings. These measurements

were repeated at 4,000, 10,000, and 20,000 cycles.

After 24,000 cycles of the test truck, strips, 6 in. wide, of garnet cloth. No. 3 grit, were placed

over the eight shoes of the walking wheel in

order to increase the abrasive action. The

strips of abrasive cloth were replaced with new

ones every 2,000 cycles. Measurements for the

depth of wear caused by the abrasive cloth on

the walking wheel were made on the various test

floors at 30,000, 40,000, and 48,000 cycles of the

test truck. After 48,000 cycles, the test floors were washed with soap and water and photographed.

IV. DESCRIPTION OF TEST

INSTALLATIONS

The 40 test installations involved 12 different

floor coverings and 11 clift'erent adhesives.

Each floor covering, with the exception of

strip wood flooring, was installed on both a concrete subfloor and a wood subfloor, using

two different methods of bonding on each type

of subfloor. An outline of the test installations

is given in table 1

V. RESULTS

The depths of the depressions in the floor coverings caused by the metal truck wheels at 10,000 cycles are recorded in table 1. The

extent of the depressions varied with the

different floor coverings on the same type of

subfloor and also with the same floor covering on different types of subfloors. The depressions appeared to resiflt more from compression

than from wear and occurred mainly within

the first 10,000 cycles of the test truck. Measurements of the depressions made by the truck

wheels were discontinued at 30,000 cycles be-- cause of failure in the bond in many of the test panels. In general, for the same fioor covering

the depressions were much greater with wood

sTibfloors than with concrete subfloors. This was apparently due to the compression and

permanent deformation of the wood subfloors

and also to the compression of the felt underlays

where used.

The leather-shod walking wheel produced

very little compression or wear on the floor coverings for the first 24,000 cycles. (See

table 1.) The principal action was to put a

polish or glaze on the floor coverings. Use of

the abrasive cloth between 24,000 and 48,000

cycles increased the rate of wear under the

walking wheel considerably (see table 1) and

dulled the surface of the floor coverings.

The average amount each floor covering was worn by 24,000 cycles of the walking wheel

covered with abrasive cloth in shown in table 2. Although this represents severe abrasive action,

such procedure was found necessary in order

to cause a measurable amomit of wear within

the limited time of the test. The averages were computed from the difference in the

results given in table 1 for depth of compression

and wear at 24,000 and 48,000 cycles.

The ball and roller casters caused very little depression in any of the floor coverings and for

this reason the measurements are not reported.

An attempt was made to measure the dimensional changes of the bonded floor coverings.

However, some of the floor coverings showed

evidence of much more expansion than the

results of the measurements would indicate,

the expansion taking place in the form of buckHng rather than displacement along the plane

of the floor. The accompanying photographs, figures 3 to

20, show the general condition of representative

installations of the different floor coverings at the end of 48,000 cycles of the equipment. The

three paths shown in the photographs are those

caused by the outer metal truck wheel, the

steel-wheel caster, and the walking wheel. The

small white dots in the photographs are refer- ence marks of white enamel used in taking the

depth measurements.

[4]
Table 1. —Test installations and results of measurements for depth of compression and wear

Test

panel

Subfloor

/-/?-- 2-L__

S-R.- S-L..

5-R . A-L- -

B-R-.

6-L-.

6-R-.

7-L..

7-7? _ S-£ - S-R.- 9-L .

9-R--

10-L.

10-R.

U-R..

12-L.. U-R..

IS-L..

IS-R. . U-L. . li-R.

.

15-L..

Conorete _ ....do Wood «_-. do--.

Concrete-

-

do Wood' Wood

Concrete.. do Wood

do

Concrete.

-

Concrete *. Wood ' Wood « -

.

Concrete... do_.- Wood'-.-

do_--

Ooncrete.

do- Wood V

15-R.

le-L.

ie,-R. 17-L.

17-R.

18- L_

18-R. l^L.

19-R20-L.

?0-R.

do-..

Concrete, do_-- Wood

do---

Concrete.

- -do Wood < --.do Concrete

Concrete Wood

Wood» - Concrete f...

Concrete Wood sleepers do

Bonding agent

lyisnin paste - f)il-has(' crinpnt, resinous..

I.isnin jiaste Oil-base cement, resinous.

.

I/i.L'iiin iiasle Resin cement, cumar resin. Lignin paste -.-.do

. - do - Resin cement, copal resin-

.

lyiL'nin i)aste Resin cement, copal resin.

-

Lignin paste -.

Casein-latex cementLignin paste

Casein-latex cementLignin paste

Varnish-base cement, phenolic resin Lignin paste. Varnish-base cement, phenolic resin Factory-applied adhesive and lignin paste. Factory-applied adhesive

Factory-applied adhesive and lignin paste. Factory-applied adhesive Lignin paste Resin cement, copal resin.

.

Lignin paste Resin cement, cumar resin . Lignin paste Petrolatum-base cement, rosin resin Lignin paste -. Petrolatum-base cement, rosin resin. Casein-latex cement

Oil-base cement, resinous - - Resin cement, copal resin - - Nailed, 2d casing nail Hot asphalt, strips dipped- Cut-back asphalt cement--. Blind nailed, 8d cut nail...

Floor covering

Type and description

Battleship linoleum; plain pattern, brown.

do.

do. do.

Inlaid linoleum; molded pattern, gray do

....dodo--- - Jaspe linoleum; streaked pattern, brown- -. ..-.do

-.-.do - do

Printed linoleum; block pattern, brown; wearing

surface, enamel,

----do

.do- .doInlaid felt-base; straight-line pattern, cream; wearing surface, linoleum composition. .-.-do---

----do ...do

Inlaid felt-base; ' straight-line pattern, gray; wearing surface, linoleum composition. do

do--

-do- Printed felt-base; flowered pattern, brown; wearing surface, enamel. do

do

do Mastic felt-base; plain pattern, maroon; wearing

surface, asphalt and pitch composition. do

-do.

do

do

Pressed fiberboard; plain pattern, brown; density

67 lb/ft.3 » do

do

do

Short-strip maple; equal-length shorts, no undercut, flat-grained, flat-back; density 47 lb/ft. ^ " do - Strip white-oak;"' clear-grade, flat-grained, flat- back; density 40 lb/ft. 3 " Strip yellow-pine; yl-grade, flat-grained, hollow- back; density 44 Ib/ft.s "

ThickAverage depth of depression caused by —

Metal

truck wheels

at

10,000 cycles

Walking wheel at—

Inches

0. 127

. 127

. 127

. 127 .077

.077

.077

.077 .096

.090

.096

.096 .076

.076 .076

. 076

.081

.081 .081

.081 '.092

'.092

*.092

'.092 .074

.074

.074

.074 .090

.090

.090 .090

.145

. 145

. 145

. 145 .796

.796

. 783

.789

Inches

0.002

.002

.011 .0)0

.003

.OO-S .016

.021

(»)

(•)

(»)

(») .005

.004

.014 .012

.006

.005 .008 .010

.009

.006 .016

.014

.009

.011 .018 .020

(»)

(') (») (0

.001

.001 .008

.008

(»)

.009

.011

.022

24,000 cycles

Inches

0. 000

.000

. 001 .002 .000

.000

.001 .005

.000

.001 .006

.007 .000

.001 .000

.000

.002

.00.3 .001 .002

.002

.002

.002

.003 .002

.003 .002

.000

.002

(0

.000 (0

.001

.000

.001 .004

(')

.001

.001

.001

48,000 cycles

Inches

0. 007 .(m

. 008

.0f)5 .010

.008

.012

.013 .007

.008

. 023 .015

.007

.008

.011 .004 .012

.010

.016

.010

.006

.010

.010

.009

.014

.014

.016 .003

.010

(0

.001

(').020

.021 .019

.017

.008

.011

.011

<• i = left half of panel: 7? = right half of panel (facing the panels from the

inside of the circular track)

.

' Color listed is the predominating color.

' .'Vverage thickness; li-in. diam. ft; 20 lb/in' pressure.

•< Average of both wheels.

' IH Ib/yd* asphalt-saturated lining felt bonded to subfloor with

adhesive listed.

/ 1 lb/yd2 dry lining felt bonded to subfloor with adhesive listed.

» Floor covering buckled considerably at early stage of test.

* Subfloor given a priminf ^oat of adhesive listed.

• No felt lining. Factory-applied adhesive of dry lignin paste on back of floor covering.

' Including adhesive.

' Adhesive remained plastic and accumulated at sides of paths of equipment. One heavy coat of a sealer.

" At 65-percent relative humidity anil 72° F temperature.

» 314 lb/yd 2 asphalt-saturated lining felt laid over subfloor.

p Subfloor given a priming coat of cut-back asphalt primer.

» Floor covering arched across subfloor.

Brief summaries of the general condition and

appearance of the various test installations are herewith presented

:

The Yi-in. battleship linoleum, test panels 1 and 2 (see fig. 3), was in very good condition at the end of the performance test. Thisre was

only slight failure in adhesion to the subfloors,

the principal failure occurring as small ridges

along the paths of the truck wheels in panel

1-L. On a wood subfloor with an asphaltsaturated lining felt the linoleum w^as moderately depressed by the metal truck wdieels. There was no evidence of fracture of the linoleum.

The standard gage inlaid linoleum, test panels

3 and 4 (see figs. 4 and 5), was in good condition

at the end of the performance test. There was some failure in adhesion to the subfloors along

the paths of the truck wheels, the worst failure

occurring in panel 4^R as distinct ridges ex- tending for the full length of this panel. On a wood subfloor with an asphalt-saturated lining

felt, test panel 4-L, the linoleum w^as moderate-

[5]
ly depressed by the metal truck wheels. With

a dry lining felt, test panel 4-R, the linoleum was depressed by the metal truck wheels to a

greater degree and was also depressed to a shght

extent by the walking wheel. There was evidence of some separation in the dry lining felt. The linoleum was fractured to a slight extent by the metal truck wheels.

Table 2.

Average wear of floor coverings after 24,000

cycles of the -walking wheel covered with abrasive cloth "

Floor covering

Battleship linoleum^

Inlaid linoleum

.Taspe linoleum Printed linoleum.-.

Inlaid felt-base Do

Printed felt-base Mastic felt-base Pressed fiberboard .

.

Short-strip maple...

Strip white-oak

Strip yellow-pine

Average

depth of wear

Inch"!!

0. nns

.009

.010 ,007

.010

.007 .010

.010

.018

.007

.010

.010

" The relative value of a floor covering should not be based entirely on

resistance to wear. Other factors should also be considered, such as cost, indentation characteristics, ease of maintenance, adherence to subfloors, resistance to tear and fracture, etc. The medium-gage jaspe linoleum, test panels

5 and 6 (see figs. 6 and 7), was in unserviceable

condition at the end of the performance test. Extensive failure in adhesion to the subfloors

and buckled ridges in the linoleum perpendicular to the travel of the test truck occurred

at an early stage of the test. The failures

appeared first under the truck wheels and in panel 6-R at 4,000 cycles. On a wood subfloor

with a dry lining felt the linoleum was appreciably depressed by the metal truck wheels and

to a slight extent by the walking wheel. There was evidence of some separation in the dry

lining felt. The hnoleum was fractured to a

considerable extent by the truck wheels and in

panel 6-R was also fractured at one blister by

the roller caster and walldug wheel.

The printed linoleum, test panels 7 and 8

(see figs. 8 and 9), was in serviceable condition

at the end of the performance test, although

the enamel printed on the surface was worn

through in spots by the abrasive action of the

walking wheel in 6,000 cycles after the wheel

had been covered with abrasive cloth. There was only slight failure in adhesion to the subfloors, the principal failures occurring as a few

small blisters along the paths of the truck wheels

in panels 7-L and 8-L. On a wood subfloor

with an asphalt-saturated lining felt the lino- leum was moderately depressed by the metal

truck wheels. There was evidence of slight

fracture of the linoleum by the metal truck

wheels in panels 7-L and 8-L.

The inlaid felt-base floor coverings, test panels 9, 10, 11, and 12 (see figs. 10, 11, 12, and

13), were in unserviceable condition at the end

of the performance test, with the possible ex- ception of panel 9-L. Failures in adhesion to the subfloors and blisters in the floor coverings

occurred along the paths of the truck wheels.

The metal truck wheels depressed the floor coverings to a moderate degree on both a concrete subfloor and a wood subfloor. The floor coverings were fractured to a considerable ex- tent by the metal truck wheels. There was

evidence of some separation of the linoleum

composition from the felt backing in panel 9-R.

The printed felt-base floor covering, test panels 13 and 14 (see figs. 14 and 15), withstood

the severe treatment of the test fairly well,

although at the end of the performance test

it was in unsatisfactory condition for additional

service. The enamel printed surface was worn

through in spots by the abrasive action of the

walldng wheel in 2,500 cycles after the wheel

had been covered with abrasive cloth. Along

the paths of the truck wheels there was evidence

of some failure in adhesion to the subfloors and some fracture of the floor covering, the worst

failure occurring in panel 13-R, where it was

foimd necessary to cut and recement the floor covering in order to remove a blister formed

by accumulation of vapor from the adhesive.

The metal truck wheels depressed the floor covering to a moderate degree on a concrete

subfloor and to a greater degree on a wood

subfloor.

The mastic felt-base floor covering, test panels

15 and 16 (see fig. 16), was in unserviceable

condition at the end of the performance test, with the possible exception of panel 15-R, al- though the adhesive used in this installation re- mained very plastic and accumulated in ridges

along the sides of the path of the testing equipment. In panel 16-R, where the same adhesive was used, the floor covering shifted toward the

inside of the track to such an extent as to necessitate its being stripped off the wood subfloor

[6]
Figure 3.

]i-in. haillcship linoleum on wood suhjloor {test panel '2-L)

.


[10]

[12]
and reset. In panels 16-L and, 1G~L failure in adhesion to the subfloors occurred along the

paths of the truck wheels and the floor covering was buckled and fractured to a considerable

extent.

I The K-in. pressed fiberboard, test panels 17 and 18 (see fig. 17), was in serviceable condition

at the end of the performance test, although the

fiberboard was appreciably worn by the abrasive action of the walking wheel. Over a concrete subfioor the fiberboards, when first installed, showed a tendency to warp, resulting

in some loose boards. There was evidence of extensive failure in adhesion to the wood subfloor in panel 18-L, permitting the tiles to chatter when tapped on the surface, and under

the action of the metal triick wheels the adhesive was pulverized and dusted out at the

joints of the boards. The fiberboard did not

appear to be compressed or fractured by the

metal truck wheels, although it showed some

deflection over a wood subfloor. The short-strip maple flooring, test panel 19

(see fig. 18), was in very good condition except

for some failure in adhesion to the concrete

subfloor. In panel 19-L the maple expanded

across the grain and formed an arch approximately one-eighth of an in. above the concrete

subfloor in the central portion of the track. In

panel 19-R some of the maple strips shifted

toward the inside of the track, leaving a slight

separation in some of the end joints. The

maple was moderately depressed by the metal

truck wheels. There was no evidence of

fracture or splintering of the maple.

The strip white-oak flooring, test panel 20-L

(see fig. 19), was in good condition at the end of

the performance test. The strips remained

rigidly bonded to the sleepers. The white oak was moderately depressed, and fractured to a

slight degree, by the metal truck wheels.

The strip yellow-pine flooring, test panel 20-R

(see fig. 20), was in fair condition at the end of

the performance test. The strips remained

rigidly bonded to the sleepers. The metal

truck wheels depressed the yellow pine to an

appreciable degree and caused some fracturing

and splintering of the flooring.

Several of the adhesives showed good adhesive strength and durability under the severe treatment of the test; however the much-lowercost lignin paste also showed good peifoniiance

as an adhesive for bonding linoleum and felt- base floor coverings to concrete or wood subfloors. Lignin paste is partially soluble in water and should not be used where exposure to moisture is probable. The oil- or viirnish-base

cements rendered durable service and had an

initial tackiness, which is a desirable property

from the standpoint of the installer. Tlie

casein-latex cement showed good performance,

although a definite interval of time is required

between the spreading of the adhesive and the

laying of the floor covering for proper tackiness

to develop. The cumar-resin cement showed

good performance. This adhesive sets very

quicldy, necessitating that it be spread in units

of a small area at one time. Laboratory tests indicate that it is not appreciably affected by

moderate exposure to moisture. The copalresin cement, consisting principally of "Manila

gum" or copal, clay, and alcohol, did not show

good performance. A definite period of time is required between the spreading of the adhesive

and the laying of the floor covering in order to prevent the formation of gas pockets under the

floor covering and at the same time have the

adhesive retain sufficient tackiness. The adhesive becomes brittle when dry and pulverizes

under severe traffic. The petrolatum-base ce- ment did not have sufficient resistance to shearing stresses to be satisfactory for bonding thin

flexible floor coverings. It did not have good

spreading consistency. Neither hot asphalt nor cold cut-back asphalt appeared adequate to prevent the movement of short-strip wood

flooring on a concrete subfloor.

VI. COMMENTS

In view of the type of occupancy for which

most of the floor coverings imder investigation

are intended, it must be emphasized that the

action of the metal truck wheels represents very

severe service to both the floor covering and the

bonding agent. Failure in either one has an

eftect on the ability of the other to withstand

service. In interpreting the results of this per- formance test as an aid in the selection of a

floor covering and a bondmg agent, the nature

of the service to which they will be subjected

should be given consideration. The desu'es of

[13]
the user with respect to specific properties and

the cost should also be considered. In this respect, sonae of the lower-cost floor coverings

and methods of bonding, even though less durable, should render economical and satis- factory service provided they are not subjected

to severe abuse and only moderate length of

service is required or where frequent replacements may be desirable, as in rental dwellings.

In general, the residts indicate that, of the

floor coverings tested, battleship linoleum, in- laid linoleum, strip white oak, and short-strip

maple are durable floor coverings even under

severe service. A better method of bonding

short-strip wood flooring to a concrete subfloor

is needed. The above-mentioned floor coverings are the higher priced of the floor coverings

tested. Of the lower-cost floor coverings

printed linoleum, strip yellow-pine, and printed

felt base showed fair performance with respect

to adherence to subfloors and resistance to severe service. They should render economical

service for a limited time mider moderate abuse.

All the linoleum and felt-base floor coverings

showed better performance on a concrete subfloor than on a wood subfloor. Obviously,

these conclusions are based on tests of goodquahty merchandise.

The complete removal of the floor coverings,

vmderlays, and adhesives from the subfloors was found to be rather diflicult and time-consuming in many of the instaUations. Wliere

occasional reinstallations may be required, ease

of removal from the subfloor should be considered in the selection of floor covering, underlay, and adhesive. Considerable difficulty was

encountered in the removal of asphalt-saturated

felt-base floor coverings and asphalt-saturated

linmg felt when used in conjunction with watermsoluble adhesives. In conjunction with lignin

paste considerable time was required for water to penetrate through cuts in the asphalt-saturated

felt and adequately loosen the bond. Dry lin- ing felt in conjunction with lignin paste was

readily removed with water. The inlaid felt- base floor covering in test panels 11 and 12 contained a plastic rubber coating between the

felt base and factory-applied adhesive and was

readily removed.

In general, when durable floor coverings are used over wood subfloors under severe traffic conditions, an underlay of asphalt-saturated

lining felt is desirable from the standpoint of indentation and durability. Wliere less durable floor coverings are used and thus occasional reinstallations probable, the use of dry

lining felt in conjunction with lignin paste over wood subfloors is preferable unless other

adequate means are provided for removal.

On concrete subfloors more drastic methods

can be employed in removing the floor coverings and adhesives without damaging the

subfloor. A performance test on additional floor coverings and adhesives is in progress.

VII. SELECTED REFERENCES

[1] W. E. Emley and C. E. Hofer, Test of floor cover- ings for post office workrooms, J. Research NBS 19, 567

(1937) RP1046. For sale by the Superintendent of Documents, U. S. Government Printing OiRce, Washington, D. C. Price 10 cents.

[2] H. L. Dryden, Research on Building Materials and Structures for Use in Low-Cost Housing, Building

Materials and Structures (1938) NBS Rep. BMSl.

(See cover page 3).

[3] Investigation of Low-Cost Floor Coverings,

NBS Letter Circular LC502-F. May be obtained free from the National Bureau of Standards, Washington,

D. C.

[4] P. A. Sigler and Myrtle B. Woodward, Indentation and Recovery of Low-Cost J'loor Coverings,

Building Materials and Structures (1939) NBS Rep.

BMS14. (See cover page 3).

Washington, August 11, 1939.

[14]
BUILDING MATERIALS AND STRUCTURES REPORTS

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The following publications in this series are now available by purchase from the

Superintendent of Documents at the prices indicated:

BMSl Research on Building Materials and Structures for Use in Low-Cost Housing 10j5 BMS2 Methods of Determining the Structural Properties of Low-Cost House Constructions-. 10^ BMS3 Suitability of Fiber Insulating Lath as a Plaster Base 10^ BMS4 Accelerated Aging of Fiber Building Boards 10^ BMS5 Structural Properties of Six Masonry Wall Constructions 15^ BMS6 Survey of Roofing Materials in the Southeastern States 15^ BMS7 Water Permeability of Masonry Walls 10^ BMS8 Methods of Investigation of Surface Treatment for Corrosion Protection of Steel 10^ BMS9 Structural Properties of the Insulated Steel Construction Co.'s "Frameless-Steel"

Constructions for Walls, Partitions, Floors, and Roofs 100 BMSIO Structural Properties of One of the "Keystone Beam Steel Floor" Constructions Sponsored by the H. H. Robertson Co 100 BMSll Structural Properties of the Curren Fabrihome Corporation's "Fabrihome" Constructions for Walls and Partitions 10(4 BMS12 Structural Properties of "Steelox" Constructions for Walls, Partitions, Floors, and Roofs

Sponsored by Steel Buildings, Inc 150 BMSl3 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

the 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 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 Constructions

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 BMS33 Plastic Calking Materials 100 BMS34 Performance Test of Floor Coverings for Use in Low-Cost Housing: Part 1 100