How To Repair Water Damaged Wallpaper
Preservation Briefs
Some of the spider web versions of the Preservation Briefs differ somewhat from the printed versions. Many illustrations are new and in color; Captions are simplified and some circuitous charts are omitted. To order hard copies of the Briefs, see Printed Publications.
The log cabin was used on this 1840 entrada metal to symbolize frontier life and egalitarianism, a platform that successfully elected William Henry Harrison to the presidency. Photograph: The State Museum of Pennsylvania, Pennsylvania Historical and Museum Commission.
PRESERVATION BRIEFS
26
The Preservation and Repair of Celebrated Log Buildings
Bruce D. Bomberger
The intent of this Brief is to present a concise history and clarification of the diversity of American log buildings and to provide bones guidance regarding their preservation and maintenance. A log building is defined as a building whose structural walls are composed of horizontally laid or vertically positioned logs. While this Brief will focus upon horizontally-laid, corner-notched log construction, and, in detail, houses every bit a building type, the bones arroyo to preservation presented here, every bit well as many of the physical treatments, can be applied to almost any kind of log construction.
Rustic log structures were a pop choice for vacation cabins in the 20th century. Photo: Courtesy, HABS Collection, NPS.
Log buildings, because of their distinct textile, physical structure, and sometimes their architectural design, tin develop their own unique deterioration problems. The information presented here is intended to convey the range of advisable preservation techniques bachelor. It does not, however, detail how to perform these treatments; this piece of work should be left to professionals experienced in the preservation of historic log buildings.
Despite the publication since the 1930s of a number of books and articles on the history of log construction in America, some misconceptions persist about log buildings. Log cabins were not the first type of shelter built by all American colonists. The term "log cabin" today is often loosely practical to whatsoever blazon of log business firm, regardless of its form and the historic context of its setting. "Log cabin" or "log firm" often conjures upwardly associations with colonial American history and rough frontier life. While unaltered colonial era buildings in general are rare, historic log buildings every bit a group are neither as old nor as rare as mostly believed. I and two-story log houses were built in towns and settlements across the country until almost the middle of the 19th century, and in many areas, especially in the West, as well as the Midwest and southern mountain regions, log connected to be a bones edifice material despite the introduction of wooden balloon frame structure. By the early 20th century, the popularity of "rustic" architecture had revived log construction throughout the country, and in many areas where information technology had not been used for decades.
Unlike western log cabins, 18th and 19th century log houses in the eastern part of the U.Southward. were almost always covered with siding or stucco. Photo: NPS files.
A distinction should be fatigued between the traditional meanings of "log motel" and "log house." "Log cabin" generally denotes a uncomplicated ane, or i-and-one-half story structure, somewhat impermanent, and less finished or less architecturally sophisticated. A "log cabin" was unremarkably synthetic with round rather than hewn, or hand-worked, logs, and it was the first generation homestead erected speedily for borderland shelter. "Log firm" historically denotes a more than permanent, hewn-log abode, either 1 or two stories, of more than complex blueprint, oft built as a 2d generation replacement. Many of the earliest 18th and early on 19th century log houses were traditionally clad, sooner or later on, with forest siding or stucco.
Historical Background return to height ▲
No other architectural grade has so captured the imagination of the American people than the log cabin. Political supporters of 1840 presidential candidate William Henry Harrison appropriated the log cabin as a campaign symbol. The log cabin was birthplace and dwelling for immature Abe Lincoln, every bit well equally other national figures, and causeless by many 19th century historians to be the very first type of house constructed by English language colonists. In 1893 Frederick Jackson Turner in his influential paper, "The Significance of the Frontier in American History" suggested that European colonists had adopted this ways of shelter from the Indians.
More contempo 20th century scholarship has demonstrated that horizontal log buildings were not the get-go form of shelter erected by all colonists in America. Nor was log construction engineering science invented here, but brought by Northern and Key European colonists. Finnish and Swedish settlers are credited with first introducing horizontal log building in the colony of New Sweden (now Pennsylvania) on the upper shores of Delaware Bay in 1638, who after passed on their tradition of log construction to the Welsh settlers in Pennsylvania.
During the 17th and 18th centuries, new waves of Eastern and Primal Europeans, including Swiss and Germans, came to America bringing their knowledge of log construction. Even the Scotch-Irish, who did not possess a log building tradition of their own, adapted the form of the stone houses of their native country to log structure, and contributed to spreading it across the frontier. In the Mississippi Valley, Colonial French fur traders and settlers had introduced vertical log structure in the 17th century.
This lodge constructed of logs in the 1880s is an example of the Adirondack style of rustic military camp architecture. Photo: NPS files.
Through the late 18th and early 19th centuries, borderland settlers erected log cabins as they cleared land, winding their way south in and forth the Appalachian valleys through the back country areas of Maryland, Virginia, the Carolinas and Georgia. They moved west beyond the Appalachian Mount barrier into the Ohio and Mississippi River valleys transporting their indispensable logcraft with them, into Kentucky and Tennessee, and every bit far to the southwest every bit eastern Texas. Log buildings are known to have been constructed as temporary shelters past soldiers during the Revolutionary War, and across the country, Americans used logs non only to build houses, simply likewise commercial structures, schools, churches, gristmills, barns, corncribs and a variety of outbuildings.
The entrance door centered in the gable end in this late-19th century log building is a typical feature of the Rocky Mountain Cabin style. Photo: NPS files.
Around the mid-19th century, successive generations of fur traders, metal prospectors, and settlers that included farmers and ranchers began to construct log buildings in the Rocky Mountains, the Northwest, California, and Alaska. In California and Alaska, Americans encountered log buildings that had been erected past Russian traders and colonists in the belatedly 18th and early on 19th centuries. Scandinavian and Finnish immigrants who settled in the Upper Midwest later in the 19th century also brought their ain log building techniques with them. And, many log structures in the Southwest, especially in New Mexico, show Hispanic influences of its early settlers.
While many parts of the country never stopped building with logs, wooden balloon frame construction had made it obsolete in some of the more populous parts of the country by nigh the mid-19th century. However, later in the century, log construction was employed in new ways. In the 1870s, wealthy Americans initiated the Bang-up Camp Movement for rustic vacation retreats in the Adirondack Mountains of upstate New York. Developers such equally William Durant, who used natural materials, including wood shingles, stone, and log—often with its bark retained to emphasize the Rustic style—designed comfortable summer houses and lodges that composite with the natural setting. Durant and other creators of the Rustic style drew upon Swiss chalets, traditional Japanese design, and other sources for uncomplicated compositions harmonious with nature.
Old Faithful Inn, Yellowstone National Park, Wyoming brought the Rustic style to the West in 1903 in an original design, and a scale befitting its setting. Photo: Courtesy, Historic American Buildings Survey, NPS.
The Adirondack or Rustic way was balanced in the West with construction of the Former True-blue Inn at Yellowstone National Park in Wyoming, designed by Robert C. Reamer, and begun in 1903. This popular resort was tremendously influential in its utilise of locally-bachelor natural materials, especially log, and gave impetus to Rustic as a true national style. From the turn of the century through the 1920s, Gustav Stickley and other leaders of the Craftsman Motility promoted exposed log construction. During the 1930s and 40s, the Civilian Conservation Corps (CCC) used log structure extensively in many of the state'southward Federal and State parks to build cabins, lean-tos, visitor centers, and maintenance and support buildings that are still in service.
Traditional Log Construction return to top ▲
Program and Form
When settlers took the arts and crafts of log structure with them onto the frontier, they successfully adapted it to regional materials, climates and terrains. Ane of the almost notable characteristics of the earliest 18th and 19th century log houses is the plan and form. The plan tin sometimes provide clues to the indigenous origin or route of migration of the original inhabitant or builder. But in the absence of corroborating documentary evidence, it is of import not to infer as well much nearly the ethnic craft traditions of a particular log house.
Historians have identified a number of traditional business firm plans and forms as prototypes. They were frequently repeated with elementary variations. The basic unit of measurement of each of these types is the one room enclosure formed past four log walls joined at their corners, called a single "pen" or "crib." The single pen was improved upon by installing interior partitions or by adding another log pen. Some variations of historic log house plans include: the typically mid-Atlantic "continental" plan, consisting of a single-pen of three rooms organized around a central hearth; the "saddlebag" or double-pen plan, composed of ii contiguous log pens; and the "dogtrot" plan, formed by 2 pens separated by an open passage space (sometimes enclosed later), all covered by a continuous roof. The continental plan originated in fundamental and eastern Europe and is attributed to 18th century German immigrants to Pennsylvania. Non-log interior partitioning walls grade the multi-room programme within the outside log walls. The saddlebag plan consists of ii adjoining log pens that share a fundamental chimney. A saddlebag is often the development of a single pen with an cease chimney, expanded by adding a second pen onto the chimney endwall. The saddlebag was built in a number of dissimilar regions beyond the country. The dogtrot plan may be seen with variation in many parts of the country, although it is sometimes, perhaps erroneously, considered the virtually typically southern, considering its covered passageway provided both air circulation and shelter from the oestrus. All these plan types were typically built in the form of one or 1-and-one-half story settlement cabins.
A somewhat different form evolved in the West effectually the middle of the 19th century which became specially distinctive of the Rocky Mountain cabin. While the entrance doorway to most earlier log houses was generally placed beneath the eaves, as a ways of adapting to the greater snowfall in the Rockies, here the archway was placed in the gable end, and sometimes protected from roof slides by a porch supported by two corner posts created by an extension of the roof across the gable wall.
From the belatedly 18th through the mid-19th centuries, Americans also congenital many substantial two-story log houses in towns throughout the eastern one-half of the country. In rural areas two-story log houses were sometimes built to replace earlier, first-generation settlement cabins, merely just as frequently the early on hewn-log house was retained and enlarged. A second story was added by removing the roof and gables, constructing a second floor, laying additional courses of logs, and building a new roof, or reassembling the old ane. Each generation of owners might expand an early log core building by adding on new log pens, or masonry or forest frame extensions. The improver of a rear ell, or infill structure to link a formerly freestanding outbuilding, such as a kitchen to the log main house was specially common. Such a layering of alterations is part of the evolution of many log buildings.
Corner Notching and Other Fastening Techniques
A log to replace the deteriorated sill is being hewn in the traditional manner with a broad axe. Photo: NPS files.
Corner notching is some other of the feature features of log construction. Well-nigh notching methods provide structural integrity, by locking the log ends in place, and give the pen rigidity and stability. Similar the floor programme, the type of corner notching can sometimes be a inkling to the ethnic craft origin of a log edifice, just it is important non to depict conclusions based just on notching details. Numerous corner notching techniques have been identified throughout the country. They range from the simple "saddle" notching, which demands minimal time and hewing skill, to the very common "5" notching or "steeple" notching, to "full dovetail" notching, one of the tightest but most time-consuming to reach, "half-dovetail" notching which is probably one of the most common, and "square" notching secured with pegs or spikes.
The notching method on some of the earliest eastern cabins and well-nigh 19th century western cabins, particularly saddle notching, left an extended log end or "crown." Crowns are especially pronounced or exaggerated in Rustic way structures, and sometimes they are cut shorter equally the wall rises, creating a buttress result at the corners of the building.
Another method of securing log ends consists of fastening logs that are laid without notching ("false notching") with tenons into vertical corner posts, or using spikes or pegs to attach them to vertical corner planks. Vertically positioned logs were secured at their top and lesser ends, normally into roof and sill plate timbers.
Selecting Logs and Assembling the Building
Although forest option was near likely to be adamant by availability, chestnut, white oak, cedar, and fir were preferred because these trees could provide long, directly, rot-resistant logs. Pine, which as well provided long straight logs, was as well used in areas where it was plentiful. Forest were frequently mixed, utilizing harder, heavier rot-resistant wood such every bit white oak for the foundation,"sill log", and lighter, more easily hewn wood such as yellow poplar for the upper log courses.
One of the principal advantages of log construction was the economy of tools required to complete a structure. A felling axe was the traditional tool for bringing downward the tree and cutting the logs to length. For many frontier and western structures the round logs were debarked or used in their original form with the bark left on, or one or more than sides of the logs were hewn flat with a broadaxe, or more finely finished with an adze as smooth thick planks. Notching was done with an axe, hatchet or saw; openings for doors and windows were ordinarily cut after the logs were ready into identify, and door and window frames, particularly jambs, were put in identify during construction to help concur the logs in place. Roof framing members and floor joists were either hewn from logs or of milled lumber. A log cabin could be raised and largely completed with every bit few as ii to 4 different tools, including a felling axe, a broad axe, and a paw saw or crosscut saw.
The upper gable walls were completed with logs if the roof was synthetic with purlins, which is more typical of Scandinavian or Finnish construction, and western and 20th century Rustic styles. However, vertical or horizontal weatherboard capsule was usually used throughout the land to cover wood-framed gables.
Chinking and Daubing
Stone or woods strips served to fill up in the chinking areas over which the daubing was applied. Photo: NPS files.
The horizontal spaces or joints between logs are usually filled with a combination of materials that together is known as "chinking" and "daubing." Chinking and daubing completed the outside walls of the log pen by sealing them against driving current of air and snowfall, helping them to shed rain, and blocking the entry of vermin. In improver, chinking and daubing could recoup for a minimal amount of hewing and save time if immediate shelter was needed. Non all types of log buildings were chinked. Corncribs, and sometimes portions of barns where ventilation was needed were not chinked. While more typical of Swedish or Finnish techniques, and not every bit mutual in American log construction, tight-fitting plank-hewn or scribed-fit round logs take little or no need for chinking and daubing.
A diversity of materials were used for chinking and daubing, including whatever was most conveniently at hand. Generally though, it is a three-role system applied in several steps. The chinking consists of two parts: first, a dry, bulky, rigid blocking, such equally wood slabs or stones is inserted into the joint, followed past a soft packing filler such equally oakum, moss, clay, or dried animal dung. Daubing, which completes the system, is the outer moisture-troweled finish layer of varying composition, just often consisting of a mixture of clay and lime or other locally available materials. Instead of daubing, carefully fitted quarter poles or narrow wood strips were sometimes nailed lengthwise across the log joints.
Chinking, specially the daubing, is the least durable office of a log building. Information technology is susceptible to groovy as a event of freeze-thaw action, structural settlement, drying of the logs, and a thermal expansion-contraction rate that differs from that of the logs. Seasonal deterioration of chinking necessitates continual inspection and regular patching or replacement.
Outside Wall Treatments
Although the outside logs of cabins in the W, and 20th century Rustic buildings are generally not covered, many 18th and 19th century log houses east of the Mississippi, with the exception of some of the simpler cabins and houses in remote or poorer areas, were covered with exterior cladding. The exterior of the log walls was covered for both aesthetic and practical reasons either as soon as the building was completed or sometime after.
Once the siding is gone, the logs may rapidly deteriorate unless another protective handling is applied. Photo: NPS files.
In some instances, the outside (and interior) of the logs was whitewashed. This served to discourage insects, and sealed hairline cracks in the daubing and fissures between the daubing and logs. Although the solubility of whitewash allows it to heal some of its ain hairline cracks with the wash of rain, like daubing information technology has to be periodically reapplied. Usually, a more permanent roofing such as wood siding or stucco was practical to the walls, which provided better insulation and protection, and reduced the maintenance of the log walls.
Sometimes log houses were sided or stuccoed later in an effort to limited a newly-achieved fiscal or social status. Many log houses were immediately sided and trimmed upon completion to disguise their unproblematic construction beneath Georgian, Federal and afterward architectural styles. Oft a log firm was covered, or recovered, when a new addition was erected in order to harmonize the whole, specially if the original core and its addition were constructed of different materials such equally log and forest frame.
Vertical wood furring strips were more often than not nailed to the logs prior to applying weatherboarding or stucco. This ensured that the walls would be plumb, and provided a base on which to attach the clapboards, or on which to nail the wood lath for stucco.
Foundations
Log edifice foundations varied considerably in quality, material, and configuration. In many cases, the foundation consisted of a continuous course of flat stones (with or without mortar), several piers consisting of rubblestone, single stones, brick, brusque vertical log pilings, or horizontal log "sleepers" set on grade. The 2 "sill logs," were laid direct upon one of these types of foundations.
Climate and intended permanence of the structure were the primary factors affecting foundation structure. The earliest log cabins, and temporary log dwellings in general, were the about probable to be synthetic on log pilings or log sleepers ready directly on grade. Where a more permanent log dwelling was intended, or where a warm, humid climate accelerated woods decay, such equally in the Southward, it was sometimes more than common to use stone piers which allowed air to circulate beneath the sill logs. Total cellars were not generally included in the original construction of near of the earliest log houses, only root cellars were often dug later.
Roofs
Log buildings were roofed with a diverseness of dissimilar framing systems and covering materials. Similar log house plans and corner notching styles, the types of roof framing systems used were often variations on item ethnic and regional carpentry traditions. In most cases wood shingles were the get-go roof roofing used on the earliest 18th and 19th century log houses. As wood shingle roofs deteriorated, many were replaced with standing seam metal roofs, many of which proceed to provide good service today. After pioneer log buildings west of the Mississippi were likely to be roofed with metal or gyre covering, or fifty-fifty with sod. Other log buildings have been re-roofed in the 20th century with cobblestone shingles. For some rustic log buildings in the West and Swell Camps in the Adirondacks, cobblestone shingles are the original historic covering fabric.
Chimneys
Indigenous tradition and regional adaptation likewise influenced chimney structure and placement. Chimneys in log houses were usually built of stone or brick, a combination of the two, or even dirt-lined, notched logs or smaller sticks. Later log buildings were ofttimes constructed with merely metal stacks to accommodate wood stoves. The chimneys of log buildings erected in common cold climates tended to be located entirely inside the firm to maximize heat retention. In the South, where winters were less astringent the chimney stack was more typically constructed exterior the log walls. With the advent of more efficient heating systems, interior chimneys were frequently demolished or relocated and rebuilt to maximize interior space.
Interior Finishes
Logs on the interiors of many of the simpler cabins and Rustic style structures were oftentimes given a flattened surface or left exposed. But, in the more finished log houses of the 18th and 19th century, they were more ordinarily covered for most of the aforementioned reasons that the outside of the logs was covered—improved insulation, ease of maintenance, aesthetics, and keeping out vermin. Covering the interior log walls with planks, lath and plaster, boards pasted with newspaper, fabric such equally muslin, or wallpaper increased their resistance to air infiltration and their insulation value. Finished walls could be cleaned and painted more easily, and plastered walls and ceilings obscured the crude log construction and prepared interior surfaces for decorative wood trim in the electric current styles.
Historical Evaluation and Damage Assessment return to summit ▲
Earlier undertaking preservation work on a historic log edifice, its history and design should be investigated, and physical condition evaluated. It is always advisable to hire a historical architect or qualified professional experienced in preservation work to supervise the project. In add-on, Country Historic Preservation Offices, regional offices of the National Park Service, and local historical commissions may also provide technical and procedural advice.
The historical investigation should be carried out in conjunction with a visual inspection of the log edifice. Physical assessment needs to be systematic and thorough. It should include taking notes, photographs or video recording, and making drawings of existing conditions, including overall and particular views. This volition serve as a record of the appearance and condition which can be referred to once work is under fashion. A physical assessment should also identify causes of deterioration, not just symptoms or manifestations and, in some instances, may need to include a structural investigation.
Foundation Inspection
The foundation of a log edifice should e'er be inspected before beginning work because, as in any building, foundation-related problems can transfer structural defects to other components of the building. Settling of the foundation is a typical status of log buildings. If settlement is not severe and is no longer active, it is not necessarily a problem. If, still, settlement is active or uneven, if it is shifting structural weight to unintended bearing points away from the intended main bearing points of the corner notches and sill log, serious wall deflections may accept resulted. Causes of settlement may include foundation or chimney stones or sill logs that have sunk into the ground, disuse of log pilings, log sleepers, or of the sill logs themselves.
Log Inspection
Foundation problems usually result in impairment to the sill logs and spandrels, which are often the nigh susceptible to deterioration. Sill logs, along with the corner notching, tend to bear virtually of the weight of the building, and are closest to vegetation and the ground, which harbors wood-destroying moisture and insects. If the sill log has come into contact with the ground, deterioration is probably underway or likely to begin. It is also important to check the drainage around the building. The building assessment should note the condition of each log and attempt to place the sources of issues that appear to exist.
Sill log inspection should not necessitate destruction of historic exterior cladding if it exists. Inspection tin can ordinarily be made in areas where cladding is missing, loose, or deteriorated. Sill log, as well as upper log, deterioration may also be revealed by loose or peeling areas of the cladding. If pieces of cladding must be removed for log inspection, they should be labeled and saved for reinstallation, or as samples for replacement piece of work. Celebrated cladding generally need non be disturbed unless there are obvious signs of settling or other indications of deterioration.
Other areas of the log walls which are particularly susceptible to deterioration include window and door sills, corner notches, and crowns, and any other areas regularly saturated past rain runoff or backsplash. The characteristic design characteristic of Adirondack or Rustic style log buildings of leaving log ends or crowns to extend beyond the notched corners of the building positions the crowns beyond the drip-line of the roof border. This makes them vulnerable to saturation from roof runoff, and a probable spot for deterioration. Saddle notching in which the cut was made out of the top surface of the log and which cups upward, and flat notching, may also be especially susceptible to collecting runoff moisture.
Detection of decay requires thorough inspection. Probing for rot should exist washed advisedly since repair techniques tin sometimes save fifty-fifty badly deteriorated logs. Soft areas should exist probed with a minor knife bract or icepick to determine the depth of decay. Logs should be gently tapped at regular intervals upwardly and down their lengths with the tool handle to detect hollow-sounding areas of possible interior disuse. Long cracks which run with the wood grain, chosen "checks," are not signs of rot, only are characteristic features of the seasoning of the logs. Nevertheless, a check can admit moisture and fungal decay into a log, especially if it is located on the log's upper surface. Checks should also be probed with a tool blade to decide whether disuse is underway inside the log.
This rotted sill cannot be repaired and must be replaced. Photograph: NPS files.
Sill log ground contact and relative moisture content too provide ideal conditions for certain types of insect infestation. Wood building members, such as sill logs or weatherboarding, less than 8 inches from the ground, should be noted equally a potential problem for monitoring or correction. Sighting of insects, or their damage, or telltale signs of their activity, such equally mud tunnels, exit holes, or "frass," a sawdust-like powder, should exist recorded. Insect infestation is all-time treated by a professionally licensed exterminator, every bit the chemicals used to kill woods-destroying insects and deter reinfestation are more often than not toxic.
Roof Inspection
Forth with the foundation, the roof is the other most vital component of any building. The roof organisation consists of, from pinnacle to lesser, the covering, ordinarily some form of shingles or metal sheeting and flashing; board capsule or roof lath strips; the framing structure, such equally rafters or purlins; the superlative log, sometimes referred to every bit the "roof plate" or "rafter plate;" and, sometimes, but not always, gutters and downspouts.
The roof and gutters should be inspected and checked for leaks both from the outside, as well as inside if possible. Inspection may reveal evidence of an earlier roof type, or covering, and sometimes remnants of more than one historic covering cloth. The roof may be the issue of a later alteration, or raised when a second story was added, or repaired every bit the consequence of tempest or fire impairment. Oftentimes, roof framing may be composed of reused material recycled from earlier buildings. Inspection of the roof framing should note its configuration and condition. Typical problems to await for are framing members that have been dislodged from their sockets in the roof plate, or that are cracked, ridge damage, sagging rafters, broken ties and braces, and disuse of exterior exposed rafter or purlin ends, especially common on Rustic manner buildings.
Other Features
The rest of the building should also be inspected as part of the overall cess, including siding, window sash and frames, door frames and leafs, chimneys, porches, and interior walls, trim, and finishes. Any of these features may exhibit deterioration problems, inherent to the textile or to a structure particular, or may show the effects of problems transmitted from elsewhere, such every bit a deformed or mis-shapen window frame resulting from a failed sill log. The inspection should notation alterations and repairs made over time, and identify those modifications which take acquired significance and should exist preserved. Nothing should exist removed or altered before it has been examined and its historical significance noted.
Preservation Treatments return to top ▲
Since excessive moisture promotes and hastens both fungal and insect set on, information technology should be dealt with immediately. Non merely must the roof and gutters be repaired—if none be, gutters should probably be added—only the foundation course should be sloped to ensure drainage away from the edifice. If the distance from the ground to the sill log or outside capsule is less than eight inches, the ground should be graded to achieve this minimum distance. Backlog vegetation and debris such equally firewood, dead leaves, or rubbish should exist cleared from the foundation perimeter, and climbing vines whose leaves retain moisture and tendrils erode daubing, should be killed and removed. Moisture issues due to faulty interior plumbing should also be remedied. Solving or reducing wet problems may in itself terminate or halt the progress of rot and forest-destroying insects.
Log Repair return to top ▲
Stabilizing and repairing a log that has been only partially damaged by decay or insects is always preferable to replacing information technology. Retaining the log, rather than substituting a new one, preserves more of the building's integrity, including historic tool marks and the wood species which may no longer be obtainable in original dimensions. Log repair can by and large be done with the log in place at less cost, in less time, and with less harm to edifice fabric, than by removing, and installing a new hewn and notched replacement log. Log repair is achieved past 2 basic methods: traditional methods of splicing in new or old wood, or through the use of epoxies. These treatments are sometimes combined, and may also be used in conjunction with reinforcing members. Celebrated log repair, whether information technology involves patching techniques or the apply of epoxies, should always exist performed only past an experienced craftsperson or architectural conservator.
Wood Splicing
Wood splicing can involve several types of techniques. Too referred to equally "piecing-in" or "Dutchman" repair, it involves treating a localized expanse of deterioration by cut out the rust-covered area of the log, and carefully carving and installing a matching, seasoned forest replacement plug or splice. The forest species, if available, and the direction and pattern of the grain should friction match that of side by side original wood. The location and depth of disuse should determine the splicing technique to be used. In a case where disuse runs deep within a log, a total-depth segment containing the affected surface area tin be cut out, severing the log completely, and a new segment of log spliced in, using angled "scarf" joints or foursquare-cut "one-half-lap" joints. The splice is secured to the severed log by angling lag screws or bolts through the upper and lower surfaces that will be concealed by daubing.
Splicing can also be performed using epoxy as an agglutinative. A log with shallow disuse on its outer face tin can be cut back to audio depth, and a half-log face spliced on, adhered with epoxy, screws or bolts. A technique for the repair of badly deteriorated log crowns involves cut them back to sound forest, and into the notching joint if necessary, and installing new crowns cut to match. Fiberglass or aluminum reinforcement rods are inserted into holes drilled into the new crowns, and into corresponding holes drilled in the ends of the original cutoff logs. Epoxy is used as an adhesive to adhere and hold the new crowns in place. Long lag screws tin can be angled upwards through the underside of the crown into the log above to provide additional back up for the repair.
Epoxy Consolidation and Repair
In some instances, epoxies may be used by themselves to consolidate and fill the voids left by deteriorated wood. Epoxies are versatile in operation, relatively easy to employ past experts, and, afterwards curing, may be shaped with woodworking tools. Their employ requires that sufficient sound wood survives for the epoxy to attach. Just they can exist used to stabilize rotted wood, render full or greater than original strength to rust-covered construction-bearing members, and to reconstitute the shape of decayed log ends. Epoxies resist decay and insects, and while epoxy itself is resistant to wet, epoxy tends to cause adjacent wood to retain moisture rather than dry out out, and if not used in the right location, tin can actually farther a standing bike of woods disuse. Hence, epoxy repairs are virtually successful in areas where they are protected from moisture. Epoxies, of which there are a multifariousness of commercially-bachelor products on the market place, are prepared in essentially ii forms: a liquid consolidant and a flexible putty filler. Each consists of a resin and a hardener which must be mixed prior to use.
The technique of treating, for an example, a decayed log crown with epoxies is begun by removing loose decayed wood, and drying the area if necessary. The rot-affected crenel and surface of the log terminate is then saturated with liquid epoxy past repeated brushing, or past soaking it in a plastic bag filled with epoxy that is fastened to the log. The porous condition of the rot-damaged forest will describe up the epoxy like a lamp wick. Once the liquid epoxy has saturated the log finish and cured, the log cease has been consolidated, and is ready for the awarding of an epoxy putty filler. The filler resin and hardener must besides be mixed, pigments must exist mixed with the filler epoxy to color the patch, and more chiefly to protect it from ultraviolet sunlight. The filler tin exist practical with a putty pocketknife, pressing it into the irregularities of the cavity. The cured patch can be worked like wood and painted with an opaque stain or a dull stop pigment to assistance it blend with surrounding wood, although epoxy repairs tin be difficult to disguise on natural, unpainted wood.
Epoxies can be used to consolidate and repair other areas of a log, including rotted internal areas which have not yet progressed to damage the log'due south outer surface. Saturation of pocket-sized internal areas tin be accomplished past drilling several random holes into the log through an area that volition exist concealed by daubing, and then pouring in liquid epoxy. If a pure resin is used, it should be a casting resin to minimize shrinkage, and information technology is best to fill up voids with a resin that contains aggregates such equally sand, or micro-balloons. Epoxy is oftentimes used by architectural conservators to strengthen deteriorated structural members. The damaged log can be strengthened by removing the deteriorated wood, and filling the void past imbedding a reinforcing bar in epoxy filler, making certain the void is properly sealed to incorporate the epoxy before using it. Sometimes larger decayed internal areas of a log tin be more easily accessed and repaired from the interior of a construction. This may be a useful technique if it can be achieved without causing undue impairment to the interior finishes in the log building. Still, despite its many advantages, epoxy may non be an appropriate treatment for all log repairs, and it should not be used in an attempt to conceal checking, or extensive log surface patching that is exposed to view, or logs that are substantially decayed or complanate.
Log Replacement
Repairing or replacing only a segment of a log is not e'er possible. Replacement of an entire log may be the simply solution if it has been substantially lost to disuse and collapsed under the weight of logs above it. Log replacement, which should be carried out merely by experienced craftspersons, is begun by temporarily supporting the logs in a higher place, and then jacking them up simply enough to insert the new log. Potential danger to the structure may include creating inadequate temporary bearing points, and crushing chinking and interior finishes which may have settled slowly into not-original positions that cannot withstand jacking.
The new sill matches the original and is a uniform replacment. Photo: NPS files.
To begin the process of log replacement, the entire length of the log must be inspected from the exterior and the interior of the structure to determine whether it supports any structural members or features, and how their load tin can be taken up by bracing during jacking and removal. On the exterior, sheathing such as weatherboard, and adjacent chinking, must be removed along the length of the log to perform this inspection. Too, on the interior, abutting partitioning walls and plaster may also need to exist removed around the log to determine what, if any, features are supported past or tied into the log to be removed.
A replacement log should be obtained to friction match the wood species of the original being removed. If information technology is a hewn log, then the replacement must be hewn to replicate the dimensions and tool marks of the original. If the aforementioned wood species cannot be obtained in the original dimensions, a substitute species may have to be used, and may even exist preferable in some instances if a more durable woods can be institute than the original forest species. Information technology should, withal, be called to match the visual characteristics of the original species as closely every bit possible.
Wood Preservatives
In almost instances, the utilize of chemic wood preservatives is not generally recommended on historic log buildings. Preservatives tend to change the color or appearance of the logs. In addition, many are toxic, they tend to leach out of the wood over fourth dimension, and similar paint, must be periodically reapplied. Many of the tardily 19th and early 20th century Rustic structures were constructed of logs with the bark left on which may provide protection, while others have been painted. All the same, some log buildings, and especially log houses that have been inappropriately stripped of historic cladding in an earlier restoration, and now show signs of weathering, such as deep checking, may be exceptions to this guidance. A preservative treatment may be worth considering in these cases. Boiled linseed oil may sometimes be appropriate to utilize on selected exposures of a building that are peculiarly vulnerable to weathering, although linseed oil does tend to darken over fourth dimension. Borate solutions, which practice non alter the color or advent of wood, may exist another of the few effective, nonhazardous preservatives available. However, borate solutions do non penetrate dry out wood well, and thus the wood must exist green or wet. Considering borate solutions are water-soluble, after treating, the forest must be coated with a water-repellent coating. In some instances, information technology may be advisable to reapply varnish where information technology was used equally the original finish handling. Pressure-treating, while effective for new forest, is non applicable to in-identify log handling, and is generally not effective for big timbers and logs considering information technology does not penetrate deeply enough.
Foundation Repair
The foundation should take good drainage, be stable, adequately support the building as well as whatever future floorloads, and keep the sill log sufficiently clear of the ground and moisture to deter disuse and insect infestation. Log buildings with cellars are less likely to suffer problems than those built upon the ground or with crawl spaces, as long as the cellar is kept dry out and ventilated. Because the foundations of many log buildings were neither dug nor laid beneath the frost-similar, they generally tend to exist susceptible to freeze-thaw ground heaving and settlement. Also, as previously noted, some foundations consisted of wooden sleepers or pilings in straight contact with the ground. If a foundation trouble is minor, such as the need for repointing or resetting a few stones, work should accost only those areas. Loose stones should be reset in their original locations if possible. A clearly inadequate foundation that has virtually disappeared into the ground, or where large areas of masonry have buckled or sunk, resulting in excessively uneven or active settlement, will need to be rebuilt using modern construction methods simply to match the historic advent.
Chinking Repair
Daubing equanimous entirely of portland cement is never advisable to use on a historic log building. Photograph: NPS files.
Repair of chinking, whether it is finished on the exterior with wooden strips or with daubing, should not be done until all log repair or replacement, structural jacking and shoring is completed, and all replacement logs have seasoned. Historically, patching and replacing daubing on a routine basis was a seasonal chore. This was because ecology factors—edifice settlement, seasonal expansion and contraction of logs, and moisture infiltration followed by freeze-thaw activity—cracks and loosens daubing. If the exterior log walls are exposed, and the chinking or daubing requires repair, as much of the remaining inner blocking filler and daubing should exist retained every bit possible. A daubing formula and tooled finish that matches the historic daubing, if known, should be used, or based on one of the mixes listed hither. For the most part, modern commercially-available chinking products are not suitable for use on historic log buildings, although an exception might be on the interior of a log building where it will be covered by plaster or woods, and will not be visible. These products tend to have a sandy appearance that may be uniform with some historic daubing, just the colour, and other visual and physical characteristics are generally incompatible with historic log surfaces.
Sections of woods chinking which are gone or cannot be fabricated weathertight should be replaced with same-sized species saplings or quarter poles cut to fit. Generally, unless bawl was used originally, it should be removed before nailing the new wood chinking replacements tightly into identify.
Analysis of daubing can be done in much the aforementioned style as mortar analysis. If that is not feasible, by crushing a loose slice of daubing its constituent parts can be exposed, which may typically include lime, sand, clay, and, every bit binders, straw or fauna pilus. The color imparted by the sand or pigmented constituents should be noted, and any areas of original daubing should be recorded with color film for later reference. Daubing that is loose or is not adhered to the logs must first be cleaned out by hand. Blocking filler should be left intact, refitting only loose pieces. (Sometimes it may exist difficult to obtain a expert bond in which case information technology may be necessary to clean out the joint entirely.) If needed, soft filler should exist added, such every bit jute or bits of fiberglass batt, pressed firmly into voids with a stick or blunt tool. Concealed reinforcement may sometimes be used, depending upon the actuality of the restoration. This can include galvanized nails partially inserted simply on the upper side of the log to allow for the daubing to move with the upper log and keep the top joint sealed, or galvanized wire mesh secured with galvanized nails. Like repointing masonry, daubing should not exist done in full sun, excessive heat or when freezing temperatures are expected. The daubing materials should exist dry out-mixed, the chinking rechecked as being tight and secure, and the mix wetted and stirred to a potent, paste-like consistency. The mix dries quickly, and so no more daubing should be prepared at a time than tin can exist practical in about 30 minutes. A test patch of new daubing, either on the building, or in a mockup elsewhere, will help exam the suitability of the formula'south color and texture match.
Before applying the daubing, the chinking area, including filler and log surfaces to be covered, should exist sprayed with water to forbid the dry filler from likewise rapidly drawing off the daubing wet which volition issue in hairline cracking. A trowel, ground to the width of the daubing, is used to press the daubing into the chinking space, and to polish the filled areas. Wide or deep chinking spaces or joints may have to be daubed in layers, to prevent sagging and separation from the logs, by applying one or ii scratch coats before finishing the surface.
Portland cement was a part of the original daubing used in many late 19th and early 20th century log buildings, and is therefore appropriate to include in repairing buildings of this period. Although a modest amount of portland cement may be added to a lime, dirt and sand mix for workability, there should non be more than one part portland cement to ii parts of lime in daubing mixes intended for most celebrated log buildings. Portland cement tends to compress and develop hairline cracks, and retain moisture, all of which tin be potentially damaging to the logs.
| Daubing Mixes | ||
|---|---|---|
| parts (book) | material | |
| MIX A | 1/4 | cement |
| ane | lime | |
| 4 | sand | |
| one/8 | dry out color | |
| hog bristles or excelsior | ||
| MIX B | six | sand |
| 4 | lime | |
| 1 | cement | |
| MIX C | i | portland cement |
| iv-8 | lime | |
| seven-10 | sand | |
Mix A Donald A. Hutsler, "Log Cabin Restoration: Guidelines for the Historical Society," American Association for State and Local History, Technical Leaflet No. 74, "History News," Vol. 29, No. 5 (May 1974.)
Mix B and C are reprinted from "Log Structures: Preservation and Problem-Solving," by Harrison Goodall and Renee Friedman, Nashville, TN: American Clan for Country and Local History, 1980.
Interior Treatments
At that place is no single appropriate way to terminate or restore the interior of a historic log house. Each building and its history is unique. The temptation should be resisted to impart an unfinished borderland character by removing plaster to betrayal interior log walls or joists in the ceiling. Instead, interior treatments should be based on existing evidence, and guided by erstwhile photographs, written documentation, and interviews with previous owners. Interior features and finishes that might exist in some 18th and 19th century log houses include forest paneled walls, wood moldings, stairs, and fireplace mantels; where they have survived, these features should exist retained. Many of the more rustic log buildings built after in the 19th or early 20th century intentionally featured exposed interior log walls, sometimes with the logs peeled and varnished. If interior plaster is severely damaged or has previously been removed, and evidence such every bit lath ghosting on the logs exists, walls should be replastered or recovered with gypsum board or dry wall to match the historic appearance.
Preserving Log Buildings in Their Historic Settings return to top ▲
Log buildings are too oftentimes viewed equally portable resources. Like other historic buildings, moved or relocated log structures can endure a loss of integrity of materials and of setting. Historic buildings listed in the National Register of Historic Places may exist subject to loss of that status if moved. Despite the popularity of dismantling and relocating log buildings, they should be moved simply as a last resort, if that is the only way to save them from demolition. If they must be moved, it is preferable that they be moved intact— that is, in one piece rather than disassembled. Disassembling and moving a log building can issue in considerable loss of the historic building materials. While the logs and roof framing members can be numbered for reassembly, dismantling a log building tin outcome in loss of such features equally foundation and chimney, chinking and daubing, exterior cladding, and interior finishes. Furthermore, log buildings can rarely exist put back together as easily as they were taken autonomously.
Summary and References return to meridian ▲
Historic log buildings regardless of whether they are of horizontal or vertical structure, or whether they are 18th century log houses or early 20th century Rustic fashion cabins, are unique. Their conservation essentially centers on the preservation and repair of the logs, and appropriate repairs to chinking and daubing, which like repointing of masonry, is necessary to ensure that most log buildings are weathertight. Log edifice preservation may be accomplished with a multifariousness of techniques including splicing and piecing-in, the use of epoxy, or a combination of patching and epoxy, and oftentimes, selected replacement. But, like whatever historic building, a log structure is a organisation that functions through the maintenance of the totality of its parts.
The exterior of many of the earliest tardily 18th and 19th century log buildings, and especially those east of the Mississippi, were commonly covered with some blazon of cladding, either horizontal or vertical wood siding, stucco, or sometimes a combination. If extant, this historic cladding, which may exist hidden under a later, non-celebrated bogus siding such as aluminum, vinyl, or asbestos, should exist preserved and repaired, or replaced if evidence indicates that it existed, as a significant character-defining feature of the building.
Acknowledgements
The author, Curator, Landis Valley Museum, Lancaster, PA, wishes to thank those experts who reviewed and commented upon the draft manuscript: James Caufield; J. Randall Cotton; Harrison Goodall; Donald A. Hutslar; Terry G. Jordan; Bernard Weisgerber; Rodd Wheaton; and National Park Service professional staff. Anne E. Grimmer is credited with directing this cooperative publication project and general editorship.
This publication has been prepared pursuant to the National Historic Preservation Act of 1966, as amended, which directs the Secretarial assistant of the Interior to develop and make available information 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.
September 1991
Reading List return to meridian ▲
Briscoe, Frank. "Wood-Destroying Insects." The Old-House Journal. Vol. XIX, No. ii (March/April 1991), pp. 3439.
Caron, Peter. "Jacking Techniques for Log Buildings." Association for Preservation Technology Bulletin. Special Issue: Alberta Culture. Vol. XX, No. 4 (1988), pp. 4254.
Cotton, J. Randall. "Log Houses in America." The Onetime-House Journal. Vol. XVIII, No. 1 (Jan/February 1990), pp. 37-44.
Elbert, Duane E., and Keith A. Sculle. Log Buildings in Illinois: Their Interpretation and Preservation. Illinois Preservation Series: Number 3. Springfield, IL: Illinois Department of Conservation, Division of Historic Sites, 1982.
Goodall, Harrison. "Log Crown Repair and Selective Replacement Using Epoxy and Fiberglass Reinforcing Rebars: Lamar Barn, Yellowstone National Park, Wyoming." Preservation Tech Notes, Exterior Woodwork Number iii. Washington, D.C.: Preservation Assistance Division, National Park Service, U.S. Section of the Interior, 1989.
___________, and Renee Friedman. Log Structures: Preservation and Problem-Solving. Nashville, TN: American Association for State and Local History, 1980.
Hutslar, Donald A. The Architecture of Migration: Log Construction in the Ohio Country, 17501850. Athens, OH: Ohio Academy Press, 1986.
____________. Log Cabin Restoration: Guidelines for the Historical Society. American Association for State and Local History Technical Leaflet 74. History News. Vol. 29, No. 5, May 1974.
Jordan, Terry Grand. American Log Buildings: An Old World Heritage. Chapel Hill, NC: The University of North Carolina Press, 1985.
Kaiser, Harvey H. Cracking Camps of the Adirondacks. Boston: David R. Godine Publisher, Inc., 1986.
Merrill, William. "Wood Deterioration: Causes, Detection and Prevention." American Clan for State and Local History Technical Leaflet 77. History News. Vol. 29, No. 8, Baronial, 1974.
Rowell, R.M., J.M. Black, L.R. Gjovik, and W.C. Feist. Protecting Log Cabins from Disuse. U.S.D.A. Woods Service Products Laboratory, General Technical Study, FPL11. Madison, WI: Wood Products Laboratory, Woods Service, U.S. Section of Agriculture, 1977.
St. George, R.A. Protecting Log Cabins, Rustic Work and Unseasoned Wood from Injurious Insects in the Eastern U.s.. Farmer'southward Bulletin No. 2104, Usa Department of Agriculture. Washington, D.C.: Authorities Printing Office, 1962 (Rev. 1970).
Tweed, William C., Laura E. Soulliere, and Henry One thousand. Law. National Park Service Rustic Architecture: 1916-1942. San Francisco, CA: Division of Cultural Resource Management, Western Regional Office, National Park Service, February 1977.
Wilson, Mary. Log Motel Studies. Cultural Resources Report No. 9. Ogden, UT: U.s.a. Department of Agronomics, Forest Service, 1984.
How To Repair Water Damaged Wallpaper,
Source: https://www.nps.gov/tps/how-to-preserve/briefs/26-log-buildings.htm
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