How To Repair Adobe Houses
Preservation Briefs
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Traditional adobe repair. Photo: Russell Lee, Farm Security Administration Collection, Library of Congress.
PRESERVATION BRIEFS
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Preservation of Historic Adobe Buildings
Whether built in the 17th century or in the 20th century, adobe buildings share common problems of maintenance and deterioration. This cursory discusses the traditional materials and structure of adobe buildings and the causes of adobe deterioration. It also makes recommendations for preserving historic adobe buildings. Past its composition, adobe construction is inclined to deteriorate; withal, the buildings tin can be made durable and renewable when properly maintained.
What is Adobe? return to acme ▲
A mixture of mud and harbinger is pressed into a mold to class an adobe brick. After the adobe brick is removed from the mold, it must dry in the open up air for a month or more earlier it tin exist used. Photograph: Russell Lee, Farm Security Administration Collection, Library of Congress.
The adobe, or sun-dried brick, is one of the oldest and most common building materials known to human being. Traditionally, adobe bricks were never kiln fired. Unbaked adobe bricks consisted of sand, sometimes gravel, dirt, water, and frequently harbinger or grass mixed together by paw, formed in wooden molds, and stale by the sun. Today some commercially bachelor adobe-like bricks are fired. These are similar in size to unbaked bricks, but accept a different texture, color, and strength. Similarly some adobe bricks have been stabilized, containing cement, cobblestone. and/or bituminous materials, simply these as well differ from traditional adobe in their appearance and force.
Traditional adobe structure techniques in North America have not varied widely for over iii-i/2 centuries. Adobe building methods employed in the Southwest in the 16th century are all the same used today. Because adobe bricks are not fired in a kiln as are clay bricks, they do non permanently harden, but remain unstable—they compress and swell constantly with their changing h2o content. Their strength besides fluctuates with their water content: the college the h2o content, the lower the strength.
San Francisco de Assisi Mission Church in Rancho de Taos, NM, was constructed of adobe between 1772 and 1819 and, because of its distinctive sculptural quality, is one of the most famous and frequently photographed of the mission churches. Photograph: HABS Collection, NPS.
Adobe will not permanently bond with metal, wood, or stone because information technology exhibits much greater movement than these other materials, either separating, swell, or twisting where they interface. Even so, many of these more stable building materials such as fired brick, wood, and lime and cement mortars are notwithstanding used in adobe structure. For example, rock may exist used for a edifice'southward foundation, and wood may be used for its roof or its lintels and doorways. In the adobe building, these materials are generally held in place by their own weight or by the compressive weight of the wall above them. Adobe structure possibilities and variations in pattern have therefore been somewhat limited by the physical constraints of the material.
Preserving and rehabilitating a deteriorated adobe building is near successful when the techniques and methods used for restoration and repairs are as similar as possible to the techniques used in the original construction.
Adobe Structure Techniques render to top ▲
The Brick
The adobe brick is molded from sand and clay mixed with h2o to a plastic consistency. Commonly, harbinger or grass is included every bit a folder. Although they do not help reinforce the bricks or give them added long-term strength, straw and grass do aid the bricks shrink more than uniformly while they dry. More of import for durability, nonetheless, is the inherent dirt-to-sand ratio institute in native soil. The prepared mud is placed in wooden forms, tamped, and leveled by mitt. The bricks are and so "turned-out" of the mold to dry on a level surface covered with straw or grass so that the bricks volition not stick. After several days of drying, the adobe bricks are set for air-curing. This consists of standing the bricks on cease for a menstruum of 4 weeks or longer.
Mortar
Historically, nearly adobe walls were composed of adobe bricks laid with mud mortar. Such mortar exhibited the same properties as the bricks: relatively weak and susceptible to the same rate of hygroscopic (wet absorptive) swelling and shrinking, thermal expansion and contraction, and deterioration. Consequently, no other material has been as successful in bonding adobe bricks. Today, cement and lime mortars are commonly used with stabilized adobe bricks, but cement mortars are incompatible with unstabilized adobe because the 2 have unlike thermal expansion and contraction rates. Cement mortals thereby accelerate the deterioration of adobe bricks since the mortars are stronger than the adobe.
Building Foundations
Early adobe building foundations varied because of the difference in local edifice practices and availability of materials. Many foundations were large and essentially synthetic, but others were almost nonexistent. Most oftentimes, adobe building foundations were constructed of bricks, fieldstones, or crenel walls (double) infilled with rubble stone, tile fragments, or seashells. Adobe buildings were rarely constructed over basements or crawlspaces.
Viga logs and savinos are seen in the interior of the adobe building. Often the wooden materials that comprise the traditional apartment adobe roof create interesting and pleasing patterns on the ceilings of interior rooms. Photo: Russell Lee, Farm Security Administration Collection, Library of Congress
Walls
Since adobe construction was load-bearing with low structural forcefulness, adobe walls tended to be massive, and seldom rose over 2 stories. In fact. the maximum height of adobe mission churches in the Southwest was approximately 35 anxiety. Often buttresses braced outside walls for added stability.
In some parts of the Southwest, it was common to identify a long wooden timber within the concluding courses of adobe bricks. This timber provided a long horizontal bearing plate for the roof thereby distributing the weight of the roof forth the wall.
Roofs
Early Southwest adobe roofs (17th-mid-19th centuries) tended to exist flat with low parapet walls. These roofs consisted of logs which supported wooden poles, and which in turn supported wooden lathing or layers of twigs covered with packed adobe world. The wood was aspen, mesquite, cedar, or whatever was available. Roughly dressed logs (called "vigas") or shaped squared timbers were spaced on close (23 anxiety or less) centers resting either on the horizontal wooden member which topped the adobe wall, or on decorated cantilevered blocks, called "corbels," which were set into the adobe wall. Traditionally, these vigas often projected through the wall facades creating the typical adobe structure item copied in the 20th century revival styles. Wooden poles about ii inches in bore (chosen "latias") were then laid across the top of the vigas. Handsplit planks (called "cedros" if cedar and "savinos" if cypress) instead of poles were used when available. In some areas, these were laid in a herringbone blueprint. In the west Texas and Tucson areas, "saguaro" (cactus) ribs were used to span between vigas. Afterward railroad transportation arrived in most areas, sawn boards and planks, much like roof sheathing, became available and was ofttimes used in late-19th and early on-20th century buildings or for repairs to earlier ones.
Side by side cedar twigs, plant fibers, or material were placed on top of the poles or planks. These served as a lathing on which the 6 or more inches of adobe earth was compacted. If planks were used, twigs were not necessary. A coating of adobe mud was and then applied overall. The flat roofs were sloped somewhat toward drains of hollowed logs (called "canales," or "gargolas"), tile, or canvas metallic that projected through the parapet walls.
Gable and hipped roofs became increasingly popular in adobe buildings in the 19th and 20th centuries. "Territorial" styles and preferences for sure materials developed. For case, roof tiles were widely used in southern California. Although the railroad brought in some wooden shingles and some terra cotta, sheet metal covering was the prevalent cloth for roofs in New Mexico.
Floors
Historically, floor materials were placed directly on the basis with piddling or no subflooring preparation. Flooring materials in adobe buildings take varied from earth to adobe brick, fired brick, tile, or flagstone (chosen "lajas"), to conventional wooden floors.
Traditional Surface Coatings return to pinnacle ▲
Adobe surfaces are notoriously fragile and need frequent maintenance. To protect the exterior and interior surfaces of new adobe walls, surface coatings such equally mud plaster, lime plaster, whitewash, and stucco have been used. Such coatings applied to the exterior of adobe structure have retarded surface deterioration by offering a renewable surface to the adobe wall. In the past, these methods accept been inexpensive and readily available to the adobe owner as a solution to periodic maintenance and visual improvement. However, recent increases in labor costs and changes in cultural and socioeconomic values have caused many adobe building owners to seek more lasting materials equally alternatives to these traditional and once inexpensive surface coatings.
Traditionally, adobe surface coatings that protected the delicate adobe building fabric were renewed every few years. Women are seen here recoating an adobe wall with mud plaster mixed with straw at Chamisal, New Mexico. Photo: Russell Lee, Farm Security Administration Collection, Library of Congress.
Mud Plaster
Mud plaster has long been used as a surface coating. Similar adobe, mud plaster is composed of clay, sand, water, and straw or grass, and therefore exhibits sympathetic backdrop to those of the original adobe. The mud plaster bonds to the adobe because the two are made of the same materials. Although applying mud plaster requires piddling skill, it is a time-consuming and laborious procedure. Once in place, the mud plaster must be smoothed. This is done past hand; sometimes deerskins, sheepskins, and small, slightly rounded stones are used to smooth the plaster to create a "polished" surface. In some areas, pink or ochre pigments are mixed into the last layer and "polished."
Whitewash
Whitewash has been used on earthen buildings since before recorded history. Consisting of ground gypsum rock, water, and clay, whitewash acts equally a sealer, which can be either brushed on the adobe wall or applied with large pieces of coarse fabric such every bit burlap.
Initially, whitewash was considered inexpensive and easy to use. But its impermanence and the price of annually renewing it has made it less popular equally a surface coating in recent years.
Lime Plaster
Lime plaster, widely used in the 19th century as both an outside and interior coating, is much harder than mud plaster. It is, however, less flexible and cracks hands. It consists of lime, sand, and water and is applied in heavy coats with trowels or brushes. To brand the lime plaster adhere to adobe, walls are often scored diagonally with hatchets, making grooves about i-one/two inches deep. The grooves are filled with a mixture of lime mortar and small chips of stone or broken roof tiles. The wall is then covered heavily with the lime plaster.
Cement Stucco
In the United States, cement stucco came into use as an adobe surface blanket in the early 20th century for the revival styles of Southwest adobe compages. Cement stucco consists of cement, sand, and water and information technology is practical with a trowel in from i to 3 coats over a wire mesh nailed to the adobe surface. This textile has been very pop because it requires little maintenance when applied over fired or stabilized adobe brick, and considering it can be hands painted.
Information technology should be noted yet, that the cement stucco does not create a bond with unfired or unstabilized adobe; it relies on the wire mesh and nails to hold it in identify. Since nails cannot bond with the adobe, a business firm surface cannot exist guaranteed. Fifty-fifty when very long nails are used, wet within the adobe may cause the nails and the wire to rust, thus, losing contact with the adobe.
Other Traditional Surface Coatings
These have included items such as paints (oil base, resin, or emulsion), portland cement washes, coatings of plant extracts, and even coatings of fresh brute claret (mainly for adobe floors). Some of these coatings are cheap and piece of cake to apply, provide temporary surface protection, and are however available to the adobe owner.
Adobe Deterioration return to top ▲
When preservation or rehabilitation is contemplated for a historic adobe building, information technology is mostly because the walls or roof of the building have deteriorated in some mode—walls may exist cracked, eroded, pitted, bulging, or the roof may be sagging. In planning the stabilization and repair of an adobe building, it is necessary:
- To determine the nature of the deterioration
- To place and correct the source of the problem causing the deterioration
- To develop rehabilitation and restoration plans that are sensitive to the integrity of the celebrated adobe building
- To develop a maintenance plan once the rehabilitation or restoration is completed.
General Communication: There are several principles that when followed generally result in a relatively stable and permanent adobe resource.
- Whenever possible, secure the services or advice of a professional architect or other preservationist skillful in adobe preservation and stabilization. Although this may exist more than costly than to "do-it-yourself," it will probably be less expensive in the long run. Working with a deteriorated adobe building is a complex and difficult process. Irreversible impairment may exist done by well-meaning simply inexperienced "restorationists." Moreover, professional assistance may exist required to interpret local code requirements.
- Never brainstorm restoration or repairs until the problems that have been causing the deterioration of the adobe have been found, analyzed, and solved. For instance, sagging or bulging walls may be the result of a problem chosen "rising damp" and/or excessive roof loads. Considering adobe deterioration is almost always the cease product of a combination of problems, it takes a trained professional to clarify the deterioration, identify the source or sources of deterioration, and halt the deterioration before full restoration begins.
- Repair or replace adobe building materials with the same types of materials used originally and use the aforementioned structure techniques. Usually the all-time and the safest procedure is to use traditional building materials. Repair or replace deteriorated adobe bricks with like adobe bricks. Repair or replace rotted wooden lintels with similar wooden lintels. The bug created past introducing different replacement materials may crusade problems far exceeding those which deteriorated the adobe in the beginning place.
Sources of Deterioration return to top ▲
The following are some common signs and sources of adobe deterioration and some common solutions. It should be cautioned again, still, that adobe deterioration is ofttimes the end-product of more than than one of these problems. The remedying of merely one of these will non necessarily arrest deterioration if others are left untreated.
Structural Damage
There are several common structural issues in adobe buildings, and while the results of these problems are easy to meet, their causes are not. Many of these problems originate from improper design or construction, insufficient foundations, weak or inadequate materials, or the effects of external forces such as wind, water, snow, or earthquakes. In any example, the services of a soils engineer and/or structural engineer knowledgeable in adobe construction may exist necessary to evaluate these problems. Solutions may involve repairing foundations, realigning leaning and bulging walls, buttressing walls, inserting new window and door lintels, and repairing or replacing badly deteriorated roof structures.
There are many tell-tale signs of structural problems in adobe buildings, the well-nigh common being cracks in walls, foundations, and roofs. In adobe, cracks are generally quite visible, but their causes may be difficult to diagnose. Some cracking is normal, such every bit the curt hairline cracks that are caused as the adobe shrinks and continues to dry out. More extensive cracking, all the same, usually indicates serious structural issues. In any example, cracks, like all structural issues, should be examined past a professional person who can make recommendations for their repair.
H2o-Related Problems
Mostly, adobe buildings deteriorate because of moisture, either excessive rainwater or ground water. Successful stabilization, restoration, and the ultimate survival of an adobe building depends upon how effectively a structure sheds water. The importance in keeping an adobe building costless from excessive wet cannot exist overestimated.
Coving at the base of this adobe wall may have been acquired by salts deposited by rising groundwater and/or rainwater splash. Photo: NPS files.
The erosive action of rainwater and the subsequent drying out of adobe roofs, parapet walls, and wall surfaces tin cause furrows, cracks, deep fissures, and pitted surfaces to form. Pelting saturated adobe loses its cohesive strength and sloughs off forming rounded corners and parapets. If left unattended, rainwater impairment can somewhen destroy adobe walls and roofs, causing their connected deterioration and ultimate collapse. Standing rainwater that accumulates at foundation level and pelting splash may cause "coving" (the hollowing-out of the wall just above form level).
Ground water (water below ground level) might be nowadays because of a spring, a high water table, improper drainage, seasonal water fluctuations, excessive found watering, or changes in grade on either side of the wall. Ground h2o rises through capillary action into the wall and causes the adobe to erode, bulge, and cove. Coving is too caused past spalling during the freeze-thaw cycles. Every bit h2o rises from the ground into the wall, the bond betwixt the clay particles in the adobe brick breaks down. In addition, dissolved minerals or salts brought up from the soil past the water tin can be deposited on or virtually the surface of the wall as the moisture evaporates. If these deposits become heavily concentrated, they as well can deteriorate the adobe cloth. As the adobe dries out, shrinkage cracks unremarkably announced; loose sections of adobe bricks and mud plaster may crumble.
A water-tight roof with proper drainage is the best protection confronting rainfall erosion. Adobe wall and roof surfaces properly maintained with traditional tiles or surface coatings generally resist the destructive effects of rainwater. Roof drains should exist in good repair and sufficient to carry rainwater run-off from the roof. In an endeavour to halt the subversive furnishings of rainwater, 19th century builders ofttimes capped parapet walls with fired bricks. These bricks were harder and better suited to conditions the erosive action of rainwater; however, the addition of a brick cap to an existing parapet wall creates a drastic change in a construction's advent and fabric. The utilise of traditional lime mortar with the fired brick is advised because it is more watertight and uniform with the harder brick.
Rainwater that has accumulated at adobe foundations should be diverted abroad from the building. This may he washed by regrading, by building gravel-filled trenches or brick, tile, or rock drip gutters, or by any technique that will effectively remove the standing rainwater. Regrading is perchance the best solution because defective gutters and trenches may in event collect and concord h2o at the base of the wall or foundation.
In repairing "coving," the damage acquired by rain splash, adobe bricks stabilized with soil cement might be considered. On the other paw, concrete patches, cement stucco, and curb-similar buttresses confronting the coving usually have a negative effect considering moisture may be attracted and trapped backside the concrete.
Cement stucco and cement patches have the potential for specific kinds of water related adobe deterioration. The thermal expansion coefficient of cement stucco is iii to x times greater than that of adobe resulting in neat of the stucco. Cracks allow both liquid water and vapor to penetrate the adobe beneath, and the stucco prevents the wall from drying.
As the moisture content of the adobe increases, there is a point at which the adobe will become soft similar putty. When the wall becomes totally saturated, the adobe mud will flow as a liquid. This varies with the sand, clay, and silt content of the adobe.
If the adobe becomes so wet that the clay reaches its plastic limit, or if the adobe is exposed to a freezethaw activity, serious damage tin result. Under the weight of the roof, the wet adobe may deform or bulge. Since the deterioration is hidden from view by the cement stucco, damage may go undetected for some time. Traditional adobe structure techniques and materials should therefore, be used to repair or rebuild parts of the walls.
The destructive furnishings of moisture on adobe buildings may exist substantially halted by several remedies.
- Shrubs, trees, and other foundation plantings may exist causing concrete damage. Their roots may be growing into the adobe, and/or they may be trapping excessive wet in their roots and conducting it into walls. Their removal might exist considered to halt this process.
- Level ground immediately adjacent to the walls may be causing poor drainage. Regrading could be considered then that the ground slopes away from the building, eliminating rainwater pools.
- The installation of basis drains may be considered. Trenches well-nigh 2 to two-1/ii feet wide and several feet deep are dug effectually the adobe edifice at the base of the walls or at the foundation if in that location is any. If the soil is weak, it may be necessary to slope the sides of the trench to foreclose cave-in of the trench and subsequent damage to the wall. The walls and bottom of the trench should be lined with a polyethylene vapor bulwark to prevent the collected h2o from saturating the surrounding soil and adobe wall. Clay tile, or plastic piping, which drain to a sump or to an open gutter, are then laid in the bottom of the trench. The trench is filled with gravel to within 6 inches of grade. The remaining excavation is and so filled to form with porous soil.
A Give-and-take of Caution: Plant removal, regrading, or trenching may be potentially destructive to archaeological remains associated with historic adobe building sites. Whatsoever disturbance of the ground should, therefore, be undertaken with prudence and careful planning.
In one case any i or all of these solutions has effectively minimized the problems of rising ground h2o, the coving and deterioration of the walls can be corrected by patching the area with new adobe mud and by applying traditional surface coatings. It should be remembered, however, that unless the capillary activity is stopped effectively, this erosive condition will certainly keep. Virtually important, surface coatings and patching only repair the effects of ground water and wind erosion, they cannot cure the cause.
Wind Erosion
Windblown sand has often been cited every bit a factor in adobe material erosion. Evidence of wind erosion is oft difficult to isolate because the results are like to h2o erosion; however, furrowing caused by wind is usually more obvious at the upper half of the wall and at the corners, while coving from rainsplash and ground water is ordinarily at the lower third of the wall.
Maintenance is the fundamental to mitigating the destructive furnishings of wind erosion. Wind damage on adobe walls and roof surfaces should be repaired with new adobe mud. Any traditional surface coating may exist applied to protect against whatever possible future subversive effects. If high wind is a continuing trouble, a wind screen or breaker might exist built, using fencing or trees. Care should be taken to plant copse far enough away from the construction and so that the roots will non destroy the foundation or trap moisture.
Vegetation, Insects, and Vermin
Vegetation and pests are natural phenomena that can advance adobe deterioration. Seeds deposited by the wind or by animals may germinate in adobe walls or roofs as they would in whatsoever soil. The action of roots may intermission down adobe bricks or crusade moisture retention which will harm the structure. Animals, birds, and insects oftentimes live in adobe structures, burrowing and nesting in walls or in foundations. These pests undermine and destroy the structural soundness of the adobe building. The possibility of termite infestation should not be disregarded since termites can travel through adobe walls as they practice through natural soil. Forest members (lintels, floors, window and door shutters, and roof members) are all vulnerable to termite attack and destruction.
It is important to rid adobe structures immediately of all plant, animal, and insect pests and to take preventive measures against their return. Seedlings should be removed from the adobe as soon as they are discovered. Big plants should exist removed carefully and so that their root systems will not dislodge adobe material. Pest control involving the use of chemicals should be examined carefully in order to appraise the immediate and longlasting effects of the chemicals on the adobe building. Professional advice in this area is of import not merely because chemicals may be transported into the walls past capillary action and have a dissentious effect on the adobe fabric, but also for reasons of human being and environmental safety.
Fabric Incompatibilities
As adobe buildings are continually swelling and shrinking, it is likely that repair work has already been carried out sometime during the life of the building. Philosophies regarding adobe preservation have changed, and and so have restoration and rehabilitation techniques. Techniques acceptable only x years ago are no longer considered appropriate. Until recently, adobe bricks have been repointed with portland cement; deteriorated wooden lintels and doors have been replaced with steel ones; and adobe walls have been sprayed with plastic or latex surface coatings. The hygroscopic nature of adobe has rendered these techniques ineffective and, most important, subversive. The high strength of portland cement mortar and stucco has caused the weaker adobe brick to crack and crumble during the differential expansion of these incompatible materials. Steel lintels are much more rigid than adobe. When the edifice expands, the adobe walls twist because they are more than flexible than the steel. Plastic and latex wall coatings have been used to seal the surface, keeping it from expanding with the rest of the brick. Portions of the wall have consequently broken off. In some instances, incompatible materials can be removed from the building without subsequently damaging the structure. Other times, this is non possible. Professional advice is therefore recommended.
Repairing and Maintaining the Celebrated Adobe Building return to top ▲
Once the adobe deterioration and any resulting structural damage is repaired, the restoration of the adobe building tin can proceed. Careful attention should be given to supervene upon, repair, and/or reproduce all damaged materials with traditional or original materials.
A traditional mixture of mud and harbinger plaster should exist applied to stabilize the outside of this house. Photo: NPS files.
Patching and Repairing Adobe Brick
In patching and replacing adobe brick. every reasonable effort should be fabricated to find clay with a texture and color similar to the original fabric. When an individual adobe brick has partially disintegrated, it may exist patched in place. The deteriorated textile may be scraped out and replaced with appropriate adobe mud. Ofttimes fragments of the original adobe brick accept been footing up, mixed with water, and reused to patch the eroded expanse. Nevertheless, some professionals advise against the reuse of material which has spalled off because it often contains a high concentration of salts.
If a substantial amount of the brick has been destroyed or spalled, commercially made adobe bricks and half-bricks can be obtained, or they may be made at the site or nearby. Generally these are 3 or iv inches thick, and ideally they are composed of unstabilized adobe (that is, without any chemic additives). The deteriorated adobe bricks should be scraped out to insert the new bricks. If about of the brick is not deteriorated, then the deteriorated portion may be replaced with a half-brick. It may be necessary to cut dorsum into undeteriorated portions of the brick to achieve a flush fit of the new or halfbricks. Spray (practice non soak) the new brick and surrounding area lightly with h2o to facilitate a better bond. Too much moisture can cause swelling. Always employ traditional adobe mud mortar.
When unabridged bricks or sections of the brick walls take to be replaced, circumspection should be exercised when buying ready-made bricks. Many are at present manufactured using stabilizing agents (portland cement, lime, or emulsified cobblestone) in their limerick. While the inclusion of these agents in new adobe bricks is a technical advocacy in their durability, they will prove incompatible with the fabric of the historic adobe edifice. Concrete blocks and cinderblocks are likewise tempting solutions to extensive adobe brick replacement; simply, like commercially stabilized adobe bricks, they are not uniform with older and more unstable adobe bricks. However, concrete blocks take been used for interior partitions successfully.
Patching and Replacing Mortar
In repairing loose and deteriorated adobe mortar, intendance should also be taken to lucifer the original cloth, color, and texture. Nearly important, never supervene upon adobe mud mortar with lime mortar or portland cement mortar. It is a common error to assume that mortar hardness or strength is a mensurate of its suitability in adobe repair or reconstruction. Mortars composed of portland cement or lime do not have the same thermal expansion rate as adobe brick. With the continual thermal expansion and wrinkle of adobe bricks, portland cement or lime mortars will cause the bricks—the weaker material—to crevice, crumble, and eventually atomize.
It is recognized, however, that some late celebrated adobe buildings have ever had portland cement or lime mortars in their initial construction. The removal and replacement of these mortars with mud mortar is not advised because their removal is normally subversive to the adobe bricks.
In repairing adobe cracks, a procedure similar to repointing masonry joints may exist used. Information technology is necessary to rake out the cracks to a depth of 2 or 3 times the width of a mortal joint to obtain a good "fundamental" (mechanical bond) of the mortar to the adobe bricks. The bricks should be sprayed lightly with water to increase the cohesive bond. A trowel or a large grout gun with new adobe mud mortar may then be used to fill up the cracks.
Repairing and Replacing Wooden Members
Rotted or termite infested wood members such equally vigas, savinos, lintels, wall braces, or flooring should be repaired or replaced. Wood should always be replaced with wood. For carved corbels, however, particularly formulated low-strength epoxy consolidants and patching compounds may be used to make repairs, thus saving original craftsmanship. Tests, however, should be made prior to repairs to check on desired results since they ordinarily are not reversible. This is an expanse of edifice repair that ought not be attempted by the amateur.
Patching and Replacing Surface Coatings
Historically, almost every adobe building surface was coated. When these coatings deteriorate, they need to be replaced. Every try should be fabricated to recoat the surface with the aforementioned fabric that originally coated the surface.
When the coating has been mud plaster, the process requires that the deteriorated mud plaster be scraped off and replaced with similar materials and similar techniques, attempting in all cases to match the repair piece of work equally closely equally possible to the original. It is always meliorate to comprehend adobe with mud plaster even though the mud plaster must be renewed more ofttimes.
The procedure is not and so simple where lime plaster and portland cement stuccos are involved. As much of the deteriorated surface coating as possible should be removed without dissentious the adobe brick fabric underneath. Never put another coat of lime plaster or portland cement stucco over a deteriorated surface blanket. If serious deterioration does exist on the surface, and then it is likely that far greater deterioration exists beneath. Generally this problem is related to water, in which example it is advisable to consult a professional.
If all-encompassing recoatings in lime plaster or portland cement stucco are necessary, the owner of an adobe edifice might consider furring out the walls with lathing, then plastering over, thus creating a moisture barrier. E'er patch with the aforementioned material that is being replaced. Although lime plaster and portland cement stucco are less satisfactory equally a surface coating, many adobe buildings have always had them as a surface blanket. Their complete removal is inadvisable as the process may prove to exist more than damaging than the natural deterioration.
Roofs
Apartment adobe roofs should be restored and maintained with their original grade and materials; however, information technology may not exist feasible or prudent to restore or reconstruct a flat adobe roof on a building if the roof has previously been modified to a gable roof with canvass metal, tiles, or wood shingles.
If an existing apartment adobe roof is restored with a fresh layer of adobe mud over an existing mud roof, intendance should be taken to temporarily support the roof during the work because adobe mud is heavier moisture than later on it has cured. If not supported, the roof may collapse or deflect. If the wooden roof supports are immune to sag during such work, the forest may accept a permanent deflection, resulting in inadequate drainage and/or "ponding" at low points. Ponding is especially damaging to adobe roofs since standing water volition eventually soak through the mud and crusade the wooden roof members to rot.
On an adobe edifice, information technology is non advisable to construct a new roof that is heavier than the roof it is replacing. If the walls below have uncorrected moisture bug, the added weight of a new roof may cause the walls to bulge (a deformation caused while the adobe mud is in a plastic state). If the walls are dry just severely deteriorated, the added weight may cause the walls to fissure or crumble (compression failure).
Floors, Windows, Doors, Etc.
Windows, doors, floors, and other original details of the older adobe building should be retained whenever feasible. It is, all the same, understandable when the demands of mod living make information technology necessary to alter some of these features: thermal windows and doors, easily maintained floors, etc. But every reasonable effort should be fabricated to retain original interior and exterior details.
Maintenance return to top ▲
Cyclical maintenance has e'er been the key to successful adobe edifice survival. As soon equally rehabilitation or restoration has been completed, some program of continuing maintenance should exist initiated. Changes in the building should specially be noted. The early stages of great, sagging, or jutting in adobe walls should be monitored regularly. All water damage should be noted and remedied at its earliest possible stages. Plant, animal, and insect damage should be halted before information technology becomes substantial. The roof should be inspected periodically. Surface coatings must be inspected frequently and repaired or replaced as the demand indicates.
Mechanical systems should exist monitored for breakdown. For instance, leaking water pipes and condensation tin be potentially more damaging to the adobe building than to a brick, stone, or frame construction. Observing adobe buildings for subtle changes and performing maintenance on a regular footing is a policy which cannot be over emphasized. It is the nature of adobe buildings to deteriorate, just cyclical maintenance tin can essentially deter this process, thus producing a relatively stable historic adobe building.
Summary and References return to top ▲
In conclusion, to try the preservation of an adobe building is well-nigh a contradiction. Adobe is a formed-world material, a niggling stronger perhaps than the soil itself, but a textile whose nature is to deteriorate. The preservation of historic adobe buildings, so, is a broader and more than complex problem than well-nigh people realize. The propensity of adobe to deteriorate is a natural, ongoing procedure. While it would be desirable to arrest that process in guild to safeguard the building, no satisfactory method has yet been developed. Competent preservation and maintenance of historic adobe buildings in the American Southwest must (i) accept the adobe material and its natural deterioration, (two) understand the building as a system, and (three) understand the forces of nature which seek to return the edifice to its original state.
Many individuals have contributed to the direction, the content and the concluding grade of this Preservation Brief. The text and illustration materials were prepared by de Teel Patterson Tiller, Architectural Historian, and David Westward. Look, AIA, Technical Preservation Services Division. Much of the technical information was based upon an unpublished report prepared under contract for this part by Ralph H. Comey, Robert C. Giebner, and Albert North. Hopper, Higher of Architecture, University of Arizona, Tucson. Valuable suggestions and comments were made by architects Eugene George, Austin, Texas; John P. Conron, Santa Fe; and David G. Battle, Santa Iron. Other staff members who provided editorial assistance include H. Ward Jandl, and Kay D. Weeks.
This publication has been prepared pursuant to the National Celebrated Preservation Act of 1966, as amended, which directs the Secretary of the Interior to develop and brand available information concerning celebrated properties. Technical Preservation Services (TPS), National Park Service prepares standards, guidelines, and other educational materials on responsible celebrated preservation treatments for a wide public.
Baronial 1978
Reading List return to superlative ▲
Baer, Kurt; and Rudinger, Hugh. Architecture of the California Missions. Los Angeles: Academy of California Press. 1958.
Boundreau. E. H. Making the Adobe Brick. Berkeley, Calif.: Fifth Street Printing, 1971.
Bunting, Bainbridge. Early on Architecture in New Mexico. Albuquerque: University of New Mexico Printing, 1976.
____________Of Earth and Timbers Made: New Mexico Architecture. Albuquerque: University of New Mexico Press. 1974
Clifton, James R. Preservation of Historic Adobe Structures: A Status Study. Washington, D.C.: National Bureau of Standards Technical Note 934, US Authorities Printing Office, Stock No. 003-00301740-0, Feb. 1977.
McHenry, Paul Graham, Jr. Adobe—Build Information technology Yourself. Tucson, Ariz.:University of Arizona Press, 1973.
Phillips, Morgan W.; and Selwyn, Judith E. Epoxies for Wood Repairs in Historic Buildings. Washington, D.C.: Heritage Conservation and Recreation Service, 1978.
Articles, Periodicals, and Bibliographies
"Adobe, Past and Present." Reprinted from El Palacio. Vol. 77, no. 4 (1971).
"An Architectural Guide to Northern New United mexican states." New Mexico Compages. Vol. 12, nos. 9 and x (Sept.October. 1970).
Adobe News. Los Lunas, New United mexican states. Published bimonthly.
Barnes, Mark R. "Adobe Bibliography." The Clan for Preservation Technology Bulletin. Vol. 7, no. 1 (1975).
Eyre, T. A. "The Physical Properties of Adobe Used as a Building Material." The Academy of New United mexican states Message. Technology Serial. Vol. i, no. 3 (1935).
George, Eugene. "Adobe Bibliography." The Association for Preservation Technology Bulletin. Vol. 5, no. four (1974).
Haapala, K. V. "Stabilizing and Restoring Sometime Adobe Structures in California." Newsletter of the National Clan of Restoration Specialists. Potato, Calif., June 1972.
Hooker, Van Dorn. "To Hand Plaster or Not?" New Mexico Architecture. Vol. 19, no. 5 (Sept.Oct. 1977).
How To Repair Adobe Houses,
Source: https://www.nps.gov/tps/how-to-preserve/briefs/5-adobe-buildings.htm
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