NBSIR 79-1730

Protecting Adobe Walls from

Ground Water

James R. Clifton

Frankie Davis

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, DC 20234

March 1979

Prepared for

-or

100

,056

79-1733

U.S. Department of Interior

•National Park Service

Washington, DC 20240

NaWonaT Btrrean of Standards MAY 14 wi

n

NBSIR 79-1730

PROTECTING ADOBE WALLS FROM

GROUND WATER

James R. Clifton

Frankie Davis

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Washington, DC 20234

March 1979

Prepared for U.S. Department of Interior

National Park Service

Washington, DC 20240

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
'
TABLE OF CONTENTS

Page

ABSTRACT iv

1. INTRODUCTION 1

2. ADOBE WALLS 1

2.1 Adobe Soils ......... .. 1 2.2 Adobe Brick 5 2.3 Construction of Test Walls. . 5

3. CAPILLARY RISE OF WATER IN TEST WALLS 5

4. PERMEABILITIES OF ADOBE MATERIALS. ........... 7

4.1 Measurement of Permeability to Water 9

4.2 Results of Permeability Testing 9

5. CHEMICAL GROUTING. 14

6. METALLIC DAMP COURSE 16

6.1 Test Procedures 16

6.2 Observations 17

7. DISCUSSION 20

8. SUMMARY AND CONCLUSIONS 22

9. REFERENCES 23

iii
ABSTRACT

Two methods for creating impervious membranes in existing adobe

walls were investigated. They were the injection of chemical grouts

and installation of a metallic membrane. Chemical grouting was

unsuccessful because of the low permeability of the tested adobe

materials. The metallic membrane did prevent the migration of moisture

in the adobe underneath the membrane, weakening the adobe. Further,

soluble salts migrated to the surface of the wet adobe. Alternative

methods for protecting adobe structures from ground water and runoff

water are discussed, including the installation of effective drainage

systems and upgrading the foundations.

Keywords: Adobe building materials; chemical grouts; damp course

membrane; metallic membrane; permeability; preservation

technology.

iv
1 INTRODUCTION

The upward migration of ground water in adobe walls is a major factor

in the processes by which water erodes and undercuts adobe structures.

It can be a serious problem in the preservation of historic adobe

structures because often they do not have waterproof foundations or

damp course membranes to prevent the rise of water by capillary action.

Usually the ground water rises in the walls to above the ground surface to

a height which depends on the equilibrium between several factors including

the rate of evaporation of moisture from the wall surface. If the ground

water has a high salt content, salts may be deposited behind the surface of

the adobe wall as the water evaporates. This can result in the undercutting

of the wall by spalling of the surface layer [1,2]. In addition, a high

moisture content can severely reduce the compressive strength and other

mechanical properties of adobe [3],

The purpose of the present study was to determine the feasibility

of creating damp course membranes in existing adobe walls by either the

injection of chemical grouts or by the insertion of metallic membranes.

In addition the effects of creating or inserting an impervious membrane

on the stability of existing adobe walls was investigated. Results

of this study are given and discussed in this report.

2. ADOBE WALLS

2.1 Adobe Soils

Adobe soils were obtained from Escalante Ruin and Tumacacori

National Monument, which are located in Arizona. Escalante Ruin is

the remains of the dwellings and other buildings of a prehistoric

1
Indian farming community, constructed from earth, located along the

Gila River. This site was occupied for several centuries between 900

to 1500 A.D. The adobe material from Escalante Ruin was taken from

the wall of a dwelling unit.

Tumacacori National Monument consists of a mission church, San Jose

de Tumacacori, and service buildings. These structures were constructed

from adobe under the direction of Franciscan priests in the early 19th

century. The existing buildings at Tumacacori are being preserved

in their present condition and adobe samples in the needed amount could

not be removed from them. Therefore, test materials, believed to be

similar to the materials used by the Franciscans, were taken from the

grounds of the site.

The adobe soils were shipped to the facilities of the National

Bureau of Standards at Gaithersburg, Maryland, in sealed drums and upon

arrival, all of the material from each site was homogenized using a

blender. Then the soils were fractionated using a 1/4 inch (6.35mm)

sieve. The material passing through sieve was used in the preparation

of test specimens.

The physical properties (Table 1) of the test materials were measured following the methods given in reference No. 4. The mineralogical

compositions of the test materials have been previously reported [5],

and are summarized in Table 1. The soil from the Tumacacori area is

richer in silt (26%) and clay (24%) than that found in adobe samples

from the church at Tumacacori (silt, 8 to 12%; clay, 8 to 12%) [5].

Therefore, sand was added to the soil to simulate the adobe in the

2
Tumacacori church. Graded sand, meeting the specifications of ASTM

C-109 [6] was added to and blended with the Tumacacori soil on an

equal weight basis. The silt and clay contents of this mixture were

18 percent and 31 percent, and this mixture is termed "Tumacacori and

Sand” in this report.

3
TABLE

1.

PHYSICAL

PROPERTIES

AND

MINERAL

COMPOSITIONS

OF

ADOBE

SOILS 33

tH

0)3

•H0 to

rH

U ». 4J

<u cu CO tH 3

CU

x 4-) tH CU 3

4-4 4-1 tH to

X 3

•H o rH a. 4-> iHN

CJ rH CO o B 4J

r-H 14H tH "3

O tH

CO o rH >4H 33 3 % o to (U O 3 3 A (U rH C4H tj cr o tH *4 4-1 CU a

cO 3 3 -d tH -a < CO CM S'? ON Oh 4-1 cO 3 3 - 3 u 00 rH CO X e 3 4-1 co 3 3 00 r^. • • • X) •H •H X rH

4-1 6^ S'? S'? CM i-H 00 rH

g s N •H 3 3 c X 1 00 m r-> CO CM 0) A o 4-1 g tH 4-1 <0 CO tH 1 rH m CM *4H CU 33 tH A 3 H

rH •H to 1 A 4-1 CU 3 3 3 rH

to

X

N •H tH 3 4-1 •rH rH o 3 i

•U

O a, cr •H 0 iH

CO •H • tH i—

o w Oh t-- CO to rH 3 o 3

O' C_>3

4-1 •H3O

rH c rH 3 •H o 3 tH rH tH O 3 o

•H

X •H CJ 0 O 0 •H 4-1 CO X A 0 3

CO CM

N

A

Q

tH •H

— S'? S'? uo 4J tH 0

tH <r

m r-^ r-- tH 3 A

O 3 s-? S'? s< S'? • • • 3 a 3 o tH cm <r >x> vo o 00 3 3 4-1 3 00 CM CM Ht CO CM or 33 •H 3 tH A rH rH X to 3 3 rH

e! tH tH HH •H 3 3 o 3 A A H Q rH Ct N N 3 4-1 4J 33 tH tH rH 3 3 3

pH & 3O 3O

•H

4-4 3 3 o XI A-N

B CM

•rH •rH 0 3- 3

4-1 tH 0 O 3 3 4J CM CM O

4-1 CO 0 110 •H O vH B CM 0 3- 4J 3 3 T3 CM O 3. CM •H B A • CM V 3 3 tH 3 •>_/ V-H 4J O 3 O N 4-1 •H a rH rH •H rH •H 0 0

CO tH o CD 3 B •H

O 3 O o > 3 4-1 >, tH rH o 31 4J to •H rH 3 3 3 rH CU rH 3 rH 3

4J

O rH i—

tH CO iH rH CJ rH 3 •H rH

tH

a r-H CJ

O CO COu 33 •H 3 CO CO

O 3 3 •H •rH 4J tH a rH co 4-> 3 CO 3 o •H 3 tH cr 3 3

t4

O 3 3 •H 1—( rn •H

Ph CO

X Cu

X Ph (XX

Properties

were

measured

using

the

methods

given

in

reference

No
2.2 Adobe Brick

Adobe bricks of dimensions 2 x 4 x 8 in (51 x 102 x 203 mm) were

prepared from the adobe soils. The water to soil ratios used in making

the bricks were 0.30, 0.15 and 0.25 for Tumacacori soil, Tumacacori and

Sand, and Escalante adobe. The soils and water were mixed in a tilting

O O drum mixer having a 1 ft J (.035 m

J

) capacity, for about 5 minutes. The

fresh pastes were placed in wooden molds which had been lightly oiled

with 20-30 weight motor oil to facilitate removal of the adobe brick.

The bricks were removed from the molds after they appeared to have

dried sufficiently to retain their shape. Then the bricks were

allowed to dry in laboratory air at 70°F (21°C) and relative humidity

near 30% for an additional month before being used.

2.3 Construction of Test Walls

Adobe wall sections were constructed using dried adobe brick and

fresh mortar having the same composition as the brick. Joints were about

5/8 in (16 mm) thick. The dimensions of the wall sections were nominal

12 x 12 x 10 in high (305 x 305 x 254 mm). Test walls were laid on two

porous concrete patio blocks (8 x 16 x 1-1/2 in (203 x 410 x 38 mm))

resting in stainless steel rectangular pans. A schematic of a test wall

is given in Figure 1. The concrete blocks allowed the upward migration

of water while providing a firm base for an adobe test wall.

3. CAPILLARY RISE OF WATER IN TEST WALLS

The capillary rise of water into two test walls constructed from

Tumacacori and Sand and Escalante adobe brick was measured. Two adjacent

vertical faces of each wall were covered with a 0.5 in (13 mm) layer

5
FIGURE I. SCHEMATIC OF AN ADOBE TEST WALL

6
of portland cement mortar. The mortar had a composition by

weight of 1 part portland cement, 2.75 parts of sand, and a water

to cement ratio of 0.45.

Specimens were removed from the walls after two weeks of testing.

Their moisture contents were obtained by drying them to constant weight

at 221°F (105°C). The data are listed in Table 2.

An analysis of the data indicates that:

(1) The mortar had little effect on the amount of rising water

accumulated in the adobe brick immediately above the concrete

block.

(2) The moisture content was relatively constant through each

brick tier.

(3) Capillary water rose in the Escalante adobe at a much higher

rate than in the Tumacacori and Sand brick.

These observations should not be taken to represent the response

of an adobe structure to ground water because of the small size of the

test wall and the short test period. However, they clearly indicate

that a large difference exists in the capillary behavior of the two

materials

4. PERMEABILITIES OF ADOBE MATERIALS

The permeabilities of the adobe soils to water were measured to

determine if they could be made less permeable to ground water by the

injection of chemical grouts. Permeability of a soil is that property

which allows the flow of a fluid through it [7], The permeability of a

soil determines if it can be grouted and the type of grout which can be

used.

7
TABLE 2. AMOUNT OF WATER IN ADOBE TEST WALLS AFTER TWO WEEKS

Moisture Content

Percent*

Wall

Material

Brick

Tier 2 3 Mortar Face * Center of Tier Adobe Face

Tumacacori

and Sand 1 22 18 26

2 13 14 13

3 8 N.M. 4

3

4 3 N.M. 4

Escalante

Adobe 1 20 N.M. 26

2 21 22 21

3 20 19 17

4 20 N.M. 17

* By weight

to making

of dry adobe. The moisture

the walls were between 2 to

contents of dried

3 percent.

adobe bricks prior

2 Side covered with portland cement mortar.

3 Taken from within one inch (25.4 mm) of the surface.

4 N.M. indicates moisture contents not measured.

8
Permeability of a soil is expressed in terms of the coefficient

of permeability (K) by the equation [7,8];

Q

= AKI

where

Q is the volume of flow per unit time; K is the coefficient

of permeability; and I is the hydraulic gradient.

The higher the value of K, greater are the chances of successfully

grouting a soil. The permeability of a soil depends on several factors

including particle size distribution, porosity, pore size distribution

and the mineralogical composition of the soil [7],

4.1 Measurement of Permeability to Water

The coefficients of permeability to water of adobe soils were

determined by the falling-head permeability test method. This method

is similar to the constant-head permeability test described in ASTM

D 2434 [9], In the constant-head method, the quantity of water flowing

through a soil specimen is measured for a given time while the head

is kept constant. The falling-head test is conducted in the same

manner, except that the head of water is not maintained constant

but is permitted to fall. The apparatus used for carrying out the

falling-head test is shown in Figure 2.

4.2 Results of Permeability Testing

No measurable flow of water was collected from the outlet tube

of the permeability test apparatus when samples of Tumacacori soil,

Tumacacori and Sand and Escalante adobe were tested. The soil specimens

slaked and separated as water slowly migrated to the top of the

specimens. The slaked soils then appeared to reconsolidate into wet

9
Figure 2. Falling Head Test Apparatus

10
masses which were highly resistant to further water flow. The

coefficients of permeability for the soils were estimated to be

less than 10 cm/sec. In general, if the permeability of a soil

is less than 10

-

^ cm/sec, the groutability of that soil is questionable

[7].

The permeability of a soil also can be estimated if its particle

size distribution is known. The relationship between effective particle diameter and the coefficient of permeability is shown in Figure 3.

The effective diameter (d-^) is the maximum diameter of the smallest 10

percent, by weight, of the soil particles. Values of d^Q were obtained

for several materials using the data given in reference No. 5 and are

listed in Table 3. Then the K values for these materials were estimated

using Figure 3. Another empirical estimate of the chemical groutability

of a soil is that if more than 20 percent, by weight, of its particles

pass through a 200 mesh sieve, there is little probability of successfully

permeating the soil with any grout [7]. Such data are also presented

in Table 3. Note that the estimated values of K are below 10~^ cm/sec

for all tested adobes and that more than 20 percent by weight of their

particles pass through a 200 mesh sieve. Therefore, it appears

unlikely that effective impervious membranes could be created in the

tested soils by injecting most types of chemical grouts.

11
PERMEABILITY, K

10 1 10-> 10-2 10-3 !0-4 10-5 10-6 10-7 cm/sec

Figure 3. Correlation of Effective Diameter, d 10 : and Permeability [7].

12
TABLE 3. ESTIMATE OF COEFFICIENT OF PERMEABILITY,

Material"*-

Turaacacori Adobe

Tutnacacori Soil

Tumacacori and Sand

Escalante Adobe

Fort Bowie Adobe

d 10

2/ mm

k

3/

cm/sec

>.002 >10"6

>.002 >10"6

>.002 >10" 6

>.002 >10"6

>.002 >10"6

K

Weight Percent

Passing Through

200 Mesh Si eve

47

92

46

52

28

* Obtained from data in reference No. 5.

2 Maximum diameter of the smallest 10%, by weight, of the soil particles.

3 Estimated using Figure 3.

13
5. CHEMICAL GROUTING

The types of chemical grouts commonly used for different soils

are given in Figure 4. The acrylamide base material appears to be

representative of the type of material most capable of penetrating

adobe materials with low coefficients of permeability. Therefore, we

attempted to grout adobe wall sections and individual adobe bricks

with it. In addition, another chemical grout with a formaldehyde

base was studied.

A grouting contractor performed the grouting application. Test

walls were constructed using brick made from Tumacacori soil, Tumacacori

and Sand, and Escalante adobe. Both chemical grouts were injected under

pressure into adobe walls at the slowest possible flow rates and at

higher rates, with the injection tube being located in the center of the

top face. The grouts did not penetrate into the adobe brick but flowed

out through small shrinkage cracks in the mortar and started to erode

the mortar joints.

In a subsequent study adobe walls and individual adobe bricks were

partially immersed in chemical grouts mixtures which had gel times ^ in

excess of 8 hours. The grouts appeared to penetrate the adobe to a depth of

less than 1 inch (25.4 mm). After the grouts had been allowed to harden for

48 hours, water was poured in the steel pans (Figure 1) until the bottom

treated portions of the adobe walls were slightly immersed. The water

resistance of the treated brick were tested by the same method. Within

a few minutes the upward migration of water was observed in both the

1 Time beyond which the viscosity of the mixtures had increased so they

would not move in the pores of the soil.

14
0.001

GRAIN SIZE IN MILLIMETERS

'ioure 4. Soil Limits for Grout Injectivity [/,10]

15
treated walls and bricks, at a rate comparable to the rise in untreated

adobe. Examination of treated adobe indicated that the grouting materials were not absorbed by the soils and did not rise in the soils by

capillary action. Clearly, it is not likely that the soils tested in

this study can be grouted using conventional methods. It is possible

that ionic chemical grouts could be made to migrate some distance in

these soils under the influence of an applied electrical field, e.g.,

electrochemical methods. Further work should be carried out to determine

if electrochemical methods could be used to sufficiently increase the

depth of penetration of chemical grouts into adobe soils so that

effective membranes could be formed.

6. METALLIC DAMP COURSE

A technique has been developed by Abotomey [11] for inserting a

damp course membrane into the walls of an existing building. This

technique involves cutting a slot through the fall thickness of a wall

and inserting a metal membrane into the slot. The membrane is the

same thickness as the slot and on insertion it becomes load bearing,

thereby reducing the amount of settlement.

The effect of using a metallic damp course membrane for preventing

the upward migration of ground water on the stability of adobe walls

was evaluated in the present study.

6.1 Test Procedures

A sheet of aluminum metal 1/16 in thick (1.6 mm) was coated on both

sides with epoxy paint to prevent its corrosion. Then it was placed

between the first and second tiers (Figure 1) as the adobe walls were

16
constructed. Walls were built using Tumacacori and Sand brick.

The mortar was allowed to dry for one month. Then water was poured

into the steel pans until the concrete patio blocks were immersed

to a depth of 3/4 in (19 mm).

The effect of the water rising to the height of the metallic

membrane or the stability of the test walls was determined. The

heights of the membrane above the patio block at the four corners

of the test walls were periodically measured using a steel ruler

with 1/32 inch gradutions (0.8 mm).

6.2 Observations

After a test period of four months it was found that the moisture

content of the adobe below the aluminum membrane had increased from

about 2 percent to about 20 percent. This was accompanied by a measurable

amount of settling in the adobe (Table 4). In addition, soluble salts

in the concrete and the adobe brick had migrated within and to

the surface of the adobe (Figure 5). As previously mentioned, the

deposition of salts behind the surface of adobe walls can result

in spalling of surface layers. These observations suggest that placing

an impermeable membrane (whether metallic or other) above the foundation

in an adobe structure can result in the settling and weakening of

the adobe below the membrane. When an ample supply of ground water is

sufficiently close to the ground surface to readily migrate up the

walls, e.g., Tumacacori church, the value of such a damp course membrane

is questionable.

17
TABLE 4 SETTLING OF ADOBE TEST WALLS WITH ALUMINUM MEMBRANE

Wall

No.

1

2

Time

4 Months

4 Months

Change in Height Between

Membrane and Patio Block^

Percent

1 2 _3

0 +2.2 -8.3

- 2.2 0 - 2.1

-2

-6

1 Measured at the four corners of the test walls (Figure 5)
Figure 5. Adobe Test Walls With Aluminum Membrane.

19
7 DISCUSSION

Results of this study suggests that it is not feasible nor desirable

to create an impervious damp course membrane in adobe walls by injecting

a chemical grout. Two commonly used chemical grouts would not adequately

penetrate the adobe tested In this study, when injected by normal pressure

techniques. While the insertion of a metallic membrane can prevent the

rise of ground water above it, water accumulating beneath the membrane

could probably lead to the undercutting of the adobe wall and a reduction

in its comprehensive strength.

Steen [12] suggested that in many cases adobe walls could be adequately

protected from both ground water and rain water accumulating at the wall

base, by the construction of drainage systems. He recommends the digging

of trenches around adobe walls and filling them with gravel of sufficient

size to prevent the rise of capillary water. However, if the ground water

is constantly present at a high level, as in the case of the Tumacacori

church [13], other solutions need to be identified.

The waterproofing of the foundation, if existing, or the underlying

soil by chemical treatment could be at least as difficult as grouting adobe

walls because of the large amounts of silt and clay present in many of the

soils. It is the opinion of the authors that only by allowing a chemical

grout to slowly infiltrate the pores of such soils is there any chance of

success. Even though the chances for success may be low, this approach

appears worthy of some evaluation using field test sites. The process may

require several days, therefore, the chemical grout must have a long gel

period. In addition, the work by Fenn [14] suggests that in general a water

thinned system is preferred to an organic solvent thinned chemical grout.

20
Haapala [15] has suggested that the foundations of old adobe

walls can be upgraded by placing concrete footing walls along each

side of the existing walls. Then the concrete walls can be waterproofed.

However, the effects of excavating and the settling of the foundations

on the adobe structure should be detemined before proceeding.

The above discussion has been concerned with possible methods for

preventing the capillary rise of ground water in adobe walls. It is

conceivable that in certain circumstances the rise of ground water

should not be completely prevented. For example, soluble salts in

adobe structures may only be harmful if the moisture content of the

adobe is fluctuating sufficiently so that the salts are being dissolved

and recrystallized or phase changes in their hydrates are occurring.

Therefore, if adobe walls are heavily laden with soluble salts, their

moisture contents possibly should be kept as constant as possible as

long as the adobe walls have adequate mechanical properties. Further,

if adobe walls have a high moisture content because of capillary water,

severe drying shrinkage could take place if the migration of ground

water is completely stopped. Clearly, further work needs to be performed

to determine the effects of changing the moisture contents and patterns

on the durability of adobe walls.

21
8. SUMMARY AND CONCLUSIONS

The feasibility of creating impervious membranes in existing adobe

walls by the injection of chemical grouts was investigated. For this

purpose, the coefficients of permeability to water of Tumacacori soil,

Tumacacori and Sand, and Escalante adobe were measured by the falling

head method. Their permeability values were all less than 10

-

^ cm/sec.

This is less than the water permeability valve of 10~^ cm/sec, which is

usually taken as the lower limit for groutability . Calculations based

on the analysis of the particle size distributions of these materials

also indicated that there is little probability of successfully grouting

them.

The grouting of adobe wall sections and individual bricks with

two commonly used chemical grouts was attempted. Two application

methods were investigated: (1) injection of the grout under pressure

into adobe test walls; and (2) soaking test walls and brick in the

liquid grouts. Neither method was successful in creating an impervious

membrane in the test specimens.

The effects of inserting metallic damp course membranes on the

durability existing adobe wall were also investigated. It was found

that settling took place in the adobe walls below the membrane. In

addition, efflorescence due to the migration of soluble salts to the

surface of the walls was observed. Therefore, the results of this

study suggests that it may not be feasible nor desirable to create an

impervious damp course membrane in adobe walls whether by injecting

a chemical grout or by the insertion of a metallic membrane.

22
9.

REFERENCES

1. Clifton, J. R., Preservation of Historic Adobe Structures-A Status

Report, NBS Technical Note 934, National Bureau of Standards

(1977).

2. Torraca, G., An International Project for the Study of Mud-Brick

Preservation in Conservation of Stone, New York Conference on Conservation of Stone and Wooden Objects, June 1970, pp. 47-57.

3. Clifton, J. R. and Davis, F. L., Mechanical Properties of Adobe,

NBS Technical Note, National Bureau of Standards (in press).

4. Clifton, J. R., Brown, P. W., and Robbins, C. R., Methods for

Characterizing Adobe Building Materials, NBS Technical Note 977,

National Bureau of Standards (1978).

5. Brown, P. W., Robbins, C. R. , and Clifton, J. R., Factors Affecting

the Durability of Adobe Structures, NBIR 78-1495, National Bureau

of Standards (1978).

6. Standard Test Method for Compressive Strength of Hydraulic Cement

Mortars (Using 2-in or 50-mm Cube Specimens), American Society

for Testing and Materials (ASTM), Designation C109-73.

7. Herndon, T. and Lenahan, T., Grouting in Soils. Volume 1.

A State-of-the-Art Report (1976); available from National Technical

Information Service, Catalog No. PB259043.

8. Herndon, J. and Lenahan, T., Grout in Soils. Volume 2. Design

and Operations Manual (1976); available from the National Technical

Information Service, Catalog No. PB259044.

9. Standard Method of Test for Permeability of Granular Soils (Constant Head), ASTM Designation D 2434-68.

10. AM-9 Chemical Grout, American Cyanamid Company (1965).

11. Abotomey, D. P., A New Load Bearing Mechanical Damp Course.

Proceedings and International Symposium on the Deterioration of

Building Stones (Athens, 1976).

12. Steen, C., An Archaeologist's Summary of Adobe, El Palacio,

Vol. 77 (No. 4), pp. 29-38 (1971).

13. Crosby, A., Preliminary Report on the Preservation Project at

Tumacacori National Monument, U.S. National Park Service (1977).

23
14. Fenn, D. B. , Second Annual Report. Chemical Stabilization of

Prehistoric Structures at Chaco Canyon National Monument, U.S.

National Park Service (1977).

15. Haapala, K.V., Stabilizing and Restoring Old Adobe Structures

in California, Newsletter of the National Association of Restoration Specialists (Murphy, California, June 1972).

24
NBS-114A IREV. 9-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 79-1730

2. Gov't. Accession 3. Recipient' a Accession No.

in

4. TITLE AND SUBTITLE

Protecting Adobe Walls From Ground Water

5. Publication Date March 1979

S. ”

7. AUTHOR(S)

James R. Clifton and Frankie L. Davis

Code

—... -Mil I 8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

No.

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, ZIP)

U.S. Department of Interior

National Park Service

Washington, D.C. 20240

13. Type of Report & Period Covered Final

r S' :

15. SUPPLEMENTARY NOTES

J Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or

literature survey, mention it here.) Two methods for creating impervious membranes in existing adobe walls were

investigated. They were the injection of chemical grouts and installation

of a metallic membrane. Chemical grouting was unsuccessful because of the

low permeability of the tested adobe materials. The metallic membrane did

prevent the migration of moisture in the adobe underneath the membrane, weakening the adobe. Further, soluble salts migrated to the surface of the wet

adobe. Alternative methods for protecting adobe structures from ground

water and runoff water are discussed, including the installation of effective

drainage systems and upgrading the foundations.

17. KEY WORDS fs ix to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name

separated by semicolons)

Ado^e building materials; chemical grouts; damp course

membrane; metallic membrane; permeability; preservation technology.

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i Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

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19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF

PRINTED PAGES

28

22. Price

$4.50

US COMM* DC