How To Build A Decorative Partial Adobe Wall

Preservation Briefs

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Traditional adobe repair. Photo: Russell Lee, Farm Security Administration Drove, Library of Congress.

PRESERVATION BRIEFS

5

Preservation of Historic Adobe Buildings

• What is Adobe?
• Adobe Construction Techniques
• Traditional Surface Coatings
• Adobe Deterioration
• Sources of Deterioration
• Repairing and Maintaining
• Maintenance
• Summary and References
• Reading Listing
• Download the PDF

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 construction of adobe buildings and the causes of adobe deterioration. Information technology also makes recommendations for preserving historic adobe buildings. Past its composition, adobe construction is inclined to deteriorate; however, the buildings can be fabricated durable and renewable when properly maintained.

What is Adobe? render to top ▲

A mixture of mud and straw is pressed into a mold to form an adobe brick. Subsequently the adobe brick is removed from the mold, it must dry in the open air for a calendar month or more than before it can be used. Photo: Russell Lee, Farm Security Assistants Drove, Library of Congress.

The adobe, or dominicus-dried brick, is ane of the oldest and most common building materials known to man. Traditionally, adobe bricks were never kiln fired. Unbaked adobe bricks consisted of sand, sometimes gravel, dirt, water, and oftentimes straw or grass mixed together by hand, formed in wooden molds, and stale by the sun. Today some commercially available adobe-similar bricks are fired. These are like in size to unbaked bricks, simply accept a unlike texture, colour, and forcefulness. Similarly some adobe bricks have been stabilized, containing cement, asphalt. and/or bituminous materials, but these also differ from traditional adobe in their appearance and strength.

Traditional adobe construction techniques in Due north America have not varied widely for over three-1/2 centuries. Adobe edifice methods employed in the Southwest in the 16th century are all the same used today. Because adobe bricks are not fired in a kiln every bit are dirt bricks, they do non permanently harden, but remain unstable—they compress and groovy constantly with their irresolute water content. Their forcefulness besides fluctuates with their water content: the higher the water content, the lower the forcefulness.

San Francisco de Assisi Mission Church in Rancho de Taos, NM, was synthetic of adobe between 1772 and 1819 and, considering of its distinctive sculptural quality, is one of the nearly famous and frequently photographed of the mission churches. Photo: HABS Collection, NPS.

Adobe will non permanently bail with metal, wood, or rock because it exhibits much greater movement than these other materials, either separating, slap-up, or twisting where they interface. Yet, many of these more stable building materials such as fired brick, woods, and lime and cement mortars are nonetheless used in adobe construction. For case, stone may exist used for a building'southward foundation, and wood may be used for its roof or its lintels and doorways. In the adobe edifice, these materials are by and large held in identify by their own weight or by the compressive weight of the wall to a higher place them. Adobe structure possibilities and variations in design have therefore been somewhat limited by the concrete constraints of the material.

Preserving and rehabilitating a deteriorated adobe building is about successful when the techniques and methods used for restoration and repairs are as similar as possible to the techniques used in the original structure.

Adobe Construction Techniques return to top ▲

The Brick

The adobe brick is molded from sand and clay mixed with water to a plastic consistency. Commonly, straw or grass is included as a binder. Although they do not help reinforce the bricks or give them added long-term strength, straw and grass do help the bricks shrink more uniformly while they dry. More important for durability, however, is the inherent clay-to-sand ratio plant in native soil. The prepared mud is placed in wooden forms, tamped, and leveled by mitt. The bricks are then "turned-out" of the mold to dry out on a level surface covered with straw or grass so that the bricks will not stick. After several days of drying, the adobe bricks are set for air-curing. This consists of standing the bricks on end for a menstruum of iv 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 (moisture absorbent) 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, simply cement mortars are incompatible with unstabilized adobe because the two take dissimilar thermal expansion and wrinkle rates. Cement mortals thereby advance the deterioration of adobe bricks since the mortars are stronger than the adobe.

Edifice Foundations

Early on adobe building foundations varied considering of the departure in local building practices and availability of materials. Many foundations were large and substantially synthetic, but others were almost nonexistent. Most oft, adobe building foundations were constructed of bricks, fieldstones, or cavity 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 incorporate the traditional flat adobe roof create interesting and pleasing patterns on the ceilings of interior rooms. Photograph: Russell Lee, Farm Security Administration Collection, Library of Congress

Walls

Since adobe construction was load-bearing with low structural strength, adobe walls tended to be massive, and seldom rose over 2 stories. In fact. the maximum superlative of adobe mission churches in the Southwest was approximately 35 anxiety. Often buttresses braced exterior walls for added stability.

In some parts of the Southwest, information technology was common to place 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 along the wall.

Roofs

Early Southwest adobe roofs (17th-mid-19th centuries) tended to be flat with low parapet walls. These roofs consisted of logs which supported wooden poles, and which in plow supported wooden lathing or layers of twigs covered with packed adobe earth. The wood was aspen, mesquite, cedar, or any was available. Roughly dressed logs (called "vigas") or shaped squared timbers were spaced on close (23 feet or less) centers resting either on the horizontal wooden member which topped the adobe wall, or on busy cantilevered blocks, called "corbels," which were fix into the adobe wall. Traditionally, these vigas oft projected through the wall facades creating the typical adobe structure detail copied in the 20th century revival styles. Wooden poles well-nigh two inches in bore (called "latias") were then laid beyond the summit of the vigas. Handsplit planks (called "cedros" if cedar and "savinos" if cypress) instead of poles were used when bachelor. In some areas, these were laid in a herringbone pattern. In the due west Texas and Tucson areas, "saguaro" (cactus) ribs were used to span betwixt vigas. Afterward railroad transportation arrived in most areas, sawn boards and planks, much like roof sheathing, became available and was often used in belatedly-19th and early-20th century buildings or for repairs to before ones.

Adjacent cedar twigs, plant fibers, or cloth were placed on height of the poles or planks. These served equally a lathing on which the half dozen or more inches of adobe earth was compacted. If planks were used, twigs were non necessary. A blanket of adobe mud was then practical overall. The flat roofs were sloped somewhat toward drains of hollowed logs (called "canales," or "gargolas"), tile, or canvass metal 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 certain materials adult. For example, roof tiles were widely used in southern California. Although the railroad brought in some wooden shingles and some terra cotta, canvas metallic roofing was the prevalent fabric for roofs in New Mexico.

Floors

Historically, flooring materials were placed directly on the ground with little or no subflooring preparation. Floor materials in adobe buildings have varied from earth to adobe brick, fired brick, tile, or flagstone (called "lajas"), to conventional wooden floors.

Traditional Surface Coatings render to acme ▲

Adobe surfaces are notoriously fragile and need frequent maintenance. To protect the exterior and interior surfaces of new adobe walls, surface coatings such every bit mud plaster, lime plaster, whitewash, and stucco have been used. Such coatings applied to the outside of adobe construction have retarded surface deterioration past offering a renewable surface to the adobe wall. In the by, these methods take been inexpensive and readily bachelor to the adobe possessor 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 edifice owners to seek more than lasting materials as alternatives to these traditional and one time cheap surface coatings.

Traditionally, adobe surface coatings that protected the delicate adobe building fabric were renewed every few years. Women are seen hither recoating an adobe wall with mud plaster mixed with straw at Chamisal, New Mexico. Photo: Russell Lee, Subcontract Security Administration Collection, Library of Congress.

Mud Plaster

Mud plaster has long been used equally a surface coating. Like adobe, mud plaster is composed of dirt, sand, water, and harbinger or grass, and therefore exhibits sympathetic properties to those of the original adobe. The mud plaster bonds to the adobe because the 2 are made of the same materials. Although applying mud plaster requires trivial skill, it is a time-consuming and laborious process. In one case in place, the mud plaster must be smoothed. This is washed by paw; sometimes deerskins, sheepskins, and small, slightly rounded stones are used to smoothen 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 basis gypsum rock, water, and clay, whitewash acts as a sealer, which can be either brushed on the adobe wall or applied with large pieces of fibroid fabric such every bit burlap.

Initially, whitewash was considered inexpensive and easy to utilise. But its impermanence and the cost of annually renewing information technology has made it less pop as a surface coating in recent years.

Lime Plaster

Lime plaster, widely used in the 19th century equally both an exterior and interior blanket, is much harder than mud plaster. It is, however, less flexible and cracks easily. It consists of lime, sand, and water and is practical in heavy coats with trowels or brushes. To make the lime plaster adhere to adobe, walls are ofttimes scored diagonally with hatchets, making grooves virtually 1-one/ii inches deep. The grooves are filled with a mixture of lime mortar and small fries of rock or cleaved roof tiles. The wall is then covered heavily with the lime plaster.

Cement Stucco

In the United States, cement stucco came into utilize equally an adobe surface blanket in the early 20th century for the revival styles of Southwest adobe architecture. Cement stucco consists of cement, sand, and water and it is practical with a trowel in from 1 to three coats over a wire mesh nailed to the adobe surface. This material has been very popular because it requires little maintenance when applied over fired or stabilized adobe brick, and because it can be easily painted.

It should be noted notwithstanding, that the cement stucco does not create a bail with unfired or unstabilized adobe; it relies on the wire mesh and nails to hold information technology in place. Since nails cannot bond with the adobe, a business firm surface cannot be guaranteed. Even when very long nails are used, moisture within the adobe may cause the nails and the wire to rust, thus, losing contact with the adobe.

Other Traditional Surface Coatings

These take included items such as paints (oil base of operations, resin, or emulsion), portland cement washes, coatings of plant extracts, and even coatings of fresh creature blood (mainly for adobe floors). Some of these coatings are inexpensive and like shooting fish in a barrel to apply, provide temporary surface protection, and are still available to the adobe possessor.

Adobe Deterioration render to peak ▲

When preservation or rehabilitation is contemplated for a historic adobe building, information technology is generally because the walls or roof of the edifice take deteriorated in some fashion—walls may be croaky, 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 identify and correct the source of the problem causing the deterioration
• To develop rehabilitation and restoration plans that are sensitive to the integrity of the historic adobe building
• To develop a maintenance programme one time the rehabilitation or restoration is completed.

Full general Advice: At that place are several principles that when followed more often than not result in a relatively stable and permanent adobe resource.

1. Whenever possible, secure the services or advice of a professional architect or other preservationist proficient in adobe preservation and stabilization. Although this may be more costly than to "do-it-yourself," it will probably be less expensive in the long run. Working with a deteriorated adobe building is a circuitous and hard process. Irreversible harm may be done past well-meaning but inexperienced "restorationists." Moreover, professional assistance may exist required to interpret local code requirements.
2. Never begin restoration or repairs until the problems that have been causing the deterioration of the adobe have been institute, analyzed, and solved. For instance, sagging or bulging walls may exist the effect of a problem called "rising damp" and/or excessive roof loads. Because adobe deterioration is almost ever the end product of a combination of problems, it takes a trained professional person to analyze the deterioration, identify the source or sources of deterioration, and halt the deterioration before full restoration begins.
3. Repair or replace adobe edifice materials with the same types of materials used originally and employ the same construction techniques. Usually the best and the safest procedure is to apply traditional building materials. Repair or supplant deteriorated adobe bricks with like adobe bricks. Repair or supersede rotted wooden lintels with similar wooden lintels. The issues created by introducing dissimilar replacement materials may cause bug 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. Information technology should be cautioned once more, however, that adobe deterioration is often the end-product of more than than one of these problems. The remedying of only ane of these will not necessarily abort deterioration if others are left untreated.

Structural Damage

There are several common structural problems in adobe buildings, and while the results of these problems are piece of cake to come across, their causes are not. Many of these bug originate from improper design or construction, bereft foundations, weak or inadequate materials, or the effects of external forces such every bit current of air, water, snow, or earthquakes. In whatsoever instance, the services of a soils engineer and/or structural engineer knowledgeable in adobe construction may be necessary to evaluate these bug. 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 issues in adobe buildings, the most mutual being cracks in walls, foundations, and roofs. In adobe, cracks are mostly quite visible, just their causes may be difficult to diagnose. Some corking is normal, such equally the brusque hairline cracks that are caused as the adobe shrinks and continues to dry out out. More extensive cracking, even so, normally indicates serious structural issues. In any instance, cracks, like all structural issues, should be examined by a professional person who can make recommendations for their repair.

Water-Related Bug

Generally, adobe buildings deteriorate because of wet, either excessive rainwater or ground water. Successful stabilization, restoration, and the ultimate survival of an adobe edifice depends upon how effectively a structure sheds h2o. The importance in keeping an adobe edifice free from excessive moisture cannot be overestimated.

Coving at the base of this adobe wall may have been caused past salts deposited by rising groundwater and/or rainwater splash. Photograph: NPS files.

The erosive action of rainwater and the subsequent drying out of adobe roofs, parapet walls, and wall surfaces can cause furrows, cracks, deep fissures, and pitted surfaces to form. Rain saturated adobe loses its cohesive forcefulness and sloughs off forming rounded corners and parapets. If left unattended, rainwater damage can eventually destroy adobe walls and roofs, causing their continued deterioration and ultimate collapse. Standing rainwater that accumulates at foundation level and rain splash may crusade "coving" (the hollowing-out of the wall just above grade level).

Footing water (h2o below ground level) might be present considering of a spring, a high water table, improper drainage, seasonal water fluctuations, excessive establish watering, or changes in grade on either side of the wall. Ground water rises through capillary action into the wall and causes the adobe to erode, burl, and cove. Coving is likewise caused by spalling during the freeze-thaw cycles. As h2o rises from the basis into the wall, the bond between the dirt particles in the adobe brick breaks downwardly. In addition, dissolved minerals or salts brought up from the soil past the water tin can be deposited on or near the surface of the wall equally the moisture evaporates. If these deposits become heavily concentrated, they also tin can deteriorate the adobe fabric. As the adobe dries out, shrinkage cracks ordinarily announced; loose sections of adobe bricks and mud plaster may crumble.

A h2o-tight roof with proper drainage is the best protection against rainfall erosion. Adobe wall and roof surfaces properly maintained with traditional tiles or surface coatings more often than not resist the subversive effects of rainwater. Roof drains should be in proficient repair and sufficient to carry rainwater run-off from the roof. In an try to halt the destructive effects of rainwater, 19th century builders often capped parapet walls with fired bricks. These bricks were harder and improve suited to weather condition the erosive activeness of rainwater; however, the addition of a brick cap to an existing parapet wall creates a drastic change in a construction'south advent and cloth. The utilise of traditional lime mortar with the fired brick is advised because information technology is more watertight and compatible with the harder brick.

Rainwater that has accumulated at adobe foundations should be diverted away from the edifice. This may he washed past regrading, by building gravel-filled trenches or brick, tile, or stone drip gutters, or past whatsoever technique that will effectively remove the standing rainwater. Regrading is perhaps the all-time solution considering defective gutters and trenches may in effect collect and hold water at the base of the wall or foundation.

In repairing "coving," the damage caused by rain splash, adobe bricks stabilized with soil cement might be considered. On the other hand, concrete patches, cement stucco, and adjourn-like buttresses confronting the coving normally have a negative effect because moisture may be attracted and trapped behind 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 three to 10 times greater than that of adobe resulting in cracking 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, at that place is a point at which the adobe will get soft like putty. When the wall becomes totally saturated, the adobe mud volition flow as a liquid. This varies with the sand, dirt, 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 outcome. Under the weight of the roof, the wet adobe may deform or bulge. Since the deterioration is subconscious from view past the cement stucco, damage may become undetected for some time. Traditional adobe structure techniques and materials should therefore, be used to repair or rebuild parts of the walls.

The destructive effects of moisture on adobe buildings may be substantially halted by several remedies.

1. Shrubs, copse, and other foundation plantings may be causing concrete damage. Their roots may be growing into the adobe, and/or they may be trapping excessive moisture in their roots and conducting information technology into walls. Their removal might be considered to halt this procedure.
2. Level basis immediately adjacent to the walls may be causing poor drainage. Regrading could exist considered so that the ground slopes away from the edifice, eliminating rainwater pools.
3. The installation of footing drains may exist considered. Trenches about 2 to ii-i/2 feet broad and several feet deep are dug effectually the adobe building at the base of the walls or at the foundation if there is any. If the soil is weak, information technology 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 water from saturating the surrounding soil and adobe wall. Dirt tile, or plastic pipe, which drain to a sump or to an open gutter, are then laid in the lesser of the trench. The trench is filled with gravel to within 6 inches of grade. The remaining excavation is then filled to grade with porous soil.

A Give-and-take of Caution: Plant removal, regrading, or trenching may be potentially subversive to archaeological remains associated with historic adobe building sites. Any disturbance of the ground should, therefore, be undertaken with prudence and careful planning.

Once whatsoever ane or all of these solutions has finer minimized the problems of rising ground water, the coving and deterioration of the walls tin 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 action is stopped effectively, this erosive condition will certainly continue. Nigh important, surface coatings and patching only repair the effects of basis water and air current erosion, they cannot cure the crusade.

Wind Erosion

Windblown sand has often been cited equally a gene in adobe fabric erosion. Evidence of current of air erosion is often difficult to isolate because the results are similar to water erosion; however, furrowing caused past current of air is usually more obvious at the upper half of the wall and at the corners, while coving from rainsplash and ground water is usually at the lower third of the wall.

Maintenance is the key to mitigating the destructive effects of wind erosion. Wind damage on adobe walls and roof surfaces should exist repaired with new adobe mud. Any traditional surface coating may be applied to protect against any possible futurity destructive furnishings. If high wind is a continuing problem, a wind screen or breaker might exist built, using fencing or trees. Care should be taken to plant copse far plenty abroad from the structure so that the roots will not destroy the foundation or trap moisture.

Vegetation, Insects, and Vermin

Vegetation and pests are natural phenomena that can advance adobe deterioration. Seeds deposited past the wind or by animals may germinate in adobe walls or roofs as they would in any soil. The action of roots may break down adobe bricks or cause wet memory which will damage the structure. Animals, birds, and insects often 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 non be overlooked since termites can travel through adobe walls as they exercise through natural soil. Forest members (lintels, floors, window and door shutters, and roof members) are all vulnerable to termite attack and destruction.

Information technology is important to rid adobe structures immediately of all found, animal, and insect pests and to take preventive measures confronting their return. Seedlings should exist removed from the adobe as soon equally they are discovered. Large plants should be removed carefully so that their root systems will non dislodge adobe material. Pest control involving the use of chemicals should be examined advisedly in order to assess the immediate and longlasting effects of the chemicals on the adobe edifice. Professional person advice in this expanse is of import not but considering chemicals may be transported into the walls past capillary activity and have a damaging effect on the adobe fabric, simply also for reasons of homo and ecology rubber.

Material Incompatibilities

As adobe buildings are continually swelling and shrinking, it is probable that repair work has already been carried out onetime during the life of the edifice. Philosophies regarding adobe preservation have changed, and so have restoration and rehabilitation techniques. Techniques acceptable only 10 years ago are no longer considered advisable. Until recently, adobe bricks accept been repointed with portland cement; deteriorated wooden lintels and doors have been replaced with steel ones; and adobe walls accept been sprayed with plastic or latex surface coatings. The hygroscopic nature of adobe has rendered these techniques ineffective and, almost important, destructive. 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 flexible than the steel. Plastic and latex wall coatings accept been used to seal the surface, keeping it from expanding with the rest of the brick. Portions of the wall take consequently broken off. In some instances, incompatible materials tin be removed from the edifice without after damaging the structure. Other times, this is not possible. Professional communication is therefore recommended.

Repairing and Maintaining the Historic Adobe Building return to meridian ▲

Once the adobe deterioration and any resulting structural damage is repaired, the restoration of the adobe building can proceed. Conscientious attending should exist given to replace, repair, and/or reproduce all damaged materials with traditional or original materials.

A traditional mixture of mud and harbinger plaster should be practical to stabilize the exterior of this house. Photograph: NPS files.

Patching and Repairing Adobe Brick

In patching and replacing adobe brick. every reasonable attempt should exist made to notice clay with a texture and colour similar to the original fabric. When an individual adobe brick has partially disintegrated, it may be patched in identify. The deteriorated material may exist scraped out and replaced with appropriate adobe mud. Often fragments of the original adobe brick have been basis upwardly, mixed with h2o, and reused to patch the eroded area. However, some professionals advise against the reuse of material which has spalled off because it frequently contains a high concentration of salts.

If a substantial amount of the brick has been destroyed or spalled, commercially made adobe bricks and one-half-bricks can be obtained, or they may exist made at the site or nearby. Generally these are 3 or 4 inches thick, and ideally they are equanimous of unstabilized adobe (that is, without any chemic additives). The deteriorated adobe bricks should be scraped out to insert the new bricks. If most of the brick is non deteriorated, then the deteriorated portion may be replaced with a one-half-brick. It may exist necessary to cut back into undeteriorated portions of the brick to reach a affluent fit of the new or halfbricks. Spray (do not soak) the new brick and surrounding expanse lightly with h2o to facilitate a amend bond. Too much moisture can crusade swelling. E'er use traditional adobe mud mortar.

When entire bricks or sections of the brick walls accept to be replaced, caution should be exercised when buying ready-fabricated bricks. Many are now manufactured using stabilizing agents (portland cement, lime, or emulsified cobblestone) in their composition. While the inclusion of these agents in new adobe bricks is a technical advocacy in their immovability, they will testify incompatible with the fabric of the historic adobe building. Concrete blocks and cinderblocks are likewise tempting solutions to all-encompassing adobe brick replacement; only, like commercially stabilized adobe bricks, they are not uniform with older and more unstable adobe bricks. However, concrete blocks have been used for interior partitions successfully.

Patching and Replacing Mortar

In repairing loose and deteriorated adobe mortar, care should too exist taken to match the original material, colour, and texture. Well-nigh of import, never replace adobe mud mortar with lime mortar or portland cement mortar. It is a mutual error to assume that mortar hardness or force is a measure of its suitability in adobe repair or reconstruction. Mortars composed of portland cement or lime do not have the same thermal expansion rate equally 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 crack, crumble, and eventually disintegrate.

It is recognized, however, that some late historic adobe buildings have always had portland cement or lime mortars in their initial construction. The removal and replacement of these mortars with mud mortar is not brash considering their removal is usually destructive to the adobe bricks.

In repairing adobe cracks, a procedure like to repointing masonry joints may be used. Information technology is necessary to rake out the cracks to a depth of two or 3 times the width of a mortal joint to obtain a good "key" (mechanical bond) of the mortar to the adobe bricks. The bricks should exist sprayed lightly with h2o to increase the cohesive bond. A trowel or a large grout gun with new adobe mud mortar may then be used to fill the cracks.

Repairing and Replacing Wooden Members

Rotted or termite infested wood members such as vigas, savinos, lintels, wall braces, or flooring should be repaired or replaced. Wood should always be replaced with wood. For carved corbels, however, specially 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 usually are not reversible. This is an expanse of building repair that ought not be attempted by the apprentice.

Patching and Replacing Surface Coatings

Historically, almost every adobe building surface was coated. When these coatings deteriorate, they demand to be replaced. Every effort should be made to recoat the surface with the same material that originally coated the surface.

When the blanket has been mud plaster, the procedure requires that the deteriorated mud plaster be scraped off and replaced with like materials and like techniques, attempting in all cases to match the repair work as closely as possible to the original. It is e'er better to cover adobe with mud plaster even though the mud plaster must be renewed more frequently.

The process is not then simple where lime plaster and portland cement stuccos are involved. As much of the deteriorated surface coating as possible should be removed without damaging the adobe brick cloth underneath. Never put some other glaze of lime plaster or portland cement stucco over a deteriorated surface coating. If serious deterioration does exist on the surface, then information technology is likely that far greater deterioration exists below. Generally this problem is related to h2o, in which case it is appropriate to consult a professional.

If extensive 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 textile that is existence replaced. Although lime plaster and portland cement stucco are less satisfactory equally a surface coating, many adobe buildings have always had them equally a surface coating. Their complete removal is inadvisable as the process may evidence to be more than damaging than the natural deterioration.

Roofs

Apartment adobe roofs should be restored and maintained with their original course and materials; nonetheless, information technology may not be feasible or prudent to restore or reconstruct a apartment adobe roof on a edifice if the roof has previously been modified to a gable roof with sheet metal, tiles, or wood shingles.

If an existing flat adobe roof is restored with a fresh layer of adobe mud over an existing mud roof, care should exist taken to temporarily support the roof during the work because adobe mud is heavier wet than subsequently information technology has cured. If not supported, the roof may collapse or deflect. If the wooden roof supports are immune to sag during such piece of work, the wood may take a permanent deflection, resulting in inadequate drainage and/or "ponding" at depression points. Ponding is especially damaging to adobe roofs since standing water will somewhen soak through the mud and cause the wooden roof members to rot.

On an adobe building, it is not advisable to construct a new roof that is heavier than the roof it is replacing. If the walls below take uncorrected moisture problems, the added weight of a new roof may cause the walls to bulge (a deformation caused while the adobe mud is in a plastic country). If the walls are dry out merely severely deteriorated, the added weight may crusade the walls to crack or crumble (pinch failure).

Floors, Windows, Doors, Etc.

Windows, doors, floors, and other original details of the older adobe building should be retained whenever feasible. Information technology is, however, understandable when the demands of modern living make it necessary to modify some of these features: thermal windows and doors, hands maintained floors, etc. But every reasonable effort should be made to retain original interior and exterior details.

Maintenance return to peak ▲

Cyclical maintenance has always been the central to successful adobe building survival. As soon as rehabilitation or restoration has been completed, some programme of continuing maintenance should be initiated. Changes in the edifice should particularly exist noted. The early on stages of cracking, sagging, or bulging in adobe walls should be monitored regularly. All water impairment should be noted and remedied at its earliest possible stages. Plant, fauna, and insect impairment should be halted before it becomes substantial. The roof should be inspected periodically. Surface coatings must be inspected frequently and repaired or replaced equally the need indicates.

Mechanical systems should exist monitored for breakdown. For instance, leaking water pipes and condensation can be potentially more damaging to the adobe edifice than to a brick, rock, or frame structure. Observing adobe buildings for subtle changes and performing maintenance on a regular footing is a policy which cannot exist over emphasized. It is the nature of adobe buildings to deteriorate, only cyclical maintenance can substantially deter this process, thus producing a relatively stable historic adobe building.

Summary and References render to tiptop ▲

In conclusion, to attempt the preservation of an adobe building is about a contradiction. Adobe is a formed-globe material, a little stronger possibly than the soil itself, simply a cloth whose nature is to deteriorate. The preservation of historic adobe buildings, then, is a broader and more complex problem than most people realize. The propensity of adobe to deteriorate is a natural, ongoing process. While it would be desirable to arrest that process in order to safeguard the edifice, no satisfactory method has nevertheless been developed. Competent preservation and maintenance of celebrated adobe buildings in the American Southwest must (one) accept the adobe material and its natural deterioration, (2) understand the building as a system, and (3) sympathise the forces of nature which seek to render the building to its original state.

Many individuals have contributed to the direction, the content and the concluding class of this Preservation Brief. The text and illustration materials were prepared by de Teel Patterson Tiller, Architectural Historian, and David Westward. Wait, AIA, Technical Preservation Services Division. Much of the technical data was based upon an unpublished report prepared under contract for this part by Ralph H. Comey, Robert C. Giebner, and Albert Northward. Hopper, College 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 One thousand. Battle, Santa Fe. Other staff members who provided editorial help include H. Ward Jandl, and Kay D. Weeks.

This publication has been prepared pursuant to the National Historic Preservation Act of 1966, as amended, which directs the Secretary of the Interior to develop and brand bachelor data concerning historic properties. Technical Preservation Services (TPS), National Park Service prepares standards, guidelines, and other educational materials on responsible historic preservation treatments for a broad public.

Baronial 1978

Reading List return to peak ▲

Baer, Kurt; and Rudinger, Hugh. Compages of the California Missions. Los Angeles: University of California Press. 1958.

Boundreau. E. H. Making the Adobe Brick. Berkeley, Calif.: 5th Street Press, 1971.

Bunting, Bainbridge. Early Architecture in New United mexican states. Albuquerque: University of New Mexico Press, 1976.

____________Of World and Timbers Made: New Mexico Architecture. Albuquerque: University of New Mexico Press. 1974

Clifton, James R. Preservation of Historic Adobe Structures: A Status Report. 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 It 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. iv (1971).

"An Architectural Guide to Northern New Mexico." New Mexico Architecture. Vol. 12, nos. 9 and 10 (Sept.Oct. 1970).

Adobe News. Los Lunas, New Mexico. Published bimonthly.

Barnes, Mark R. "Adobe Bibliography." The Association for Preservation Engineering science Bulletin. Vol. seven, no. i (1975).

Eyre, T. A. "The Physical Properties of Adobe Used as a Building Material." The University of New Mexico Bulletin. Engineering Series. Vol. i, no. iii (1935).

George, Eugene. "Adobe Bibliography." The Clan for Preservation Technology Bulletin. Vol. 5, no. 4 (1974).

Haapala, Yard. V. "Stabilizing and Restoring Old Adobe Structures in California." Newsletter of the National Association of Restoration Specialists. Murphy, Calif., June 1972.

Hooker, Van Dorn. "To Mitt Plaster or Not?" New Mexico Architecture. Vol. 19, no. 5 (Sept.October. 1977).

Source: https://www.nps.gov/tps/how-to-preserve/briefs/5-adobe-buildings.htm

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