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STRUCTURAL INSPECTIONS & DEFECTS
ADVANCED INSPECTION METHODS
AGE of a BUILDING - how to determine
ARCHITECTURE, STYLE, & Building Age
DEFINITIONS of MOBILE HOME, DOUBLEWIDE, MODULAR, PANELIZED CONSTRUCTION
DEFINITIONS of ENGINEERED WOOD OSB LVL etc
FLOOR, ENGINEERED WOOD & LAMINATES
MOBILE HOMES, DOUBLEWIDES, TRAILERS
MODULAR HOME CONSTRUCTION
STAINS on & in BUILDINGS, CAUSES & CURES
WOOD STRUCTURE ASSESSMENT
This article provides a photo guide to determining building age by examining its structure. We describe building framing materials used in different epochs of residential construction. Knowing when certain materials were first or last in common use can help determine the age of a building. We list various kinds of building materials and give the history and dates of their first (and in some cases last) use in residential and light commercial construction.
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The age of a building can be determined quite accurately by documentation, but when documents are not readily available, visual clues such as those available during a professional home inspection can still determine when a house was built. Our page top photo shows modern floor framing details for a modular-constructed house.
The observation of framing materials, framing markings, and framing styles provides considerable information about the probable age of a house. We discuss framing materials and styles here as an aid to house age determination. Antique and modern trusses are distinguished and modern laminated beams and I-truss beams and wood joists are discussed.
At above left our photo illustrates a modern (21st century) post-and-beam construction using milled timbers but traditional mortise and tenon and treenail connectors.
Asbestos-Cement Board & Fiberboard Products
Exterior Siding & Roofing Using Asbestos Cement included asbestos cement shingles, asbestos cement siding, corrugated asbestos-cement roofing.
Modern Cement Board & Fiber Cement Products
Cement board is a non-structural building sheathing material which in its contemporary form is made from Portland cement covered with a reinforced fiberglass mesh fabric. Cement board is used as a tile backer or a backer board for stucco applications on buildings. Current producers include Custom Building Products (WonderBoard™) and US Gypsum (Durock™).
Panels made of a mixture of cement and wood fibers are produced for building siding by James Hardi (Hardi-panel and Cemplank™), and CertainTeed (Weatherboard™).
(History & dates in process, contributions invited - CONTACT us)
Dimensional lumber that initially actually measured as equal to its nominal size (a 2x4 was actually 2" x 4") was produced beginning in 1833 in the U.S. (Augustine Taylor, building St. Mary's church in Chicago in that year) and was the dominant framing material in the U.S. by 1900.
Our photo (left) shows the interior of a modern platform-framed structure going up in Minneapolis, MN in 2008.
The appeal of dimensional lumber was the reduced time and effort to construct a wood frame building compared with hewn timber frame beams that had to be cut and shaped, air dried for two years, and joined with mortise and tenon joints that required more highly skilled carpenters.
Initially church members were concerned that their building was being built of flimsy too-small sticks and scaffolding materials.
But 2x4 and other dimensional lumber did not remain exactly the same physical size as its nominal size, and by 1940 or earlier the finished size of most framing lumber products was notably less than the nominal size. A modern 2x4 is approximately 1 1/2" x 3 1/2" in cross section.
Is Modern 2x Pine Lumber as Strong as Antique 2x Pine Lumber?
Our opinion is that modern dimensional lumber is not the same product as it was in 1833 or even 1940. Modern 2x lumber is produced from trees that have been developed to grow rapidly to a size at which they can be harvested.
Rapid tree growth means wide-spaced growth rings which may mean softer, weaker wood than dense-grained first-cut timbers or lumber.
That combined with the increasing number of knots (as 2x's are cut from ever smaller trees) means that the building frame must rely on additional materials (such as plywood or OSB sheathing) for a critical part of its strength.
Details about the evolution of lumber standards are at FRAMING SIZE & Spacing, Age, Types.
Also see FRAMING TABLES, SPANS.
Where lumber strength vs. size, weight, or bending resistance is a particular design concern, architects and engineers may specify an engineered wood product such as a laminate-beam or wooden I-trusses or trusses where that strength is needed.
Other framing material & hardware details can assist in determining building age. An examination of nails and fasteners and other building hardware is a complimentary effort useful in determining the age of a building and its components. (NAILS & HARDWARE, AGE).
as well as SAW CUTS, TOOL MARKS, AGE for additional building age clues likely to be available when examining building framing materials.
Our photo (above left) shows a modern laminated wood structural beam in both side and end view. (Make sure that your builder uses proper connectors and supporting posts, not the goofy structural setup in our photo). Our photo of I-joists (above right) shows this engineered floor support system in use in a Minneapolis home under construction in 2008.
Fiberboard wall sheathing, when intended for use on a building exterior is installed by nailing directly to the wall studs, most often with let-in diagonal bracing or plywood panel bracing at the building corners to assure building rigidity.
There both non-structural and structural fiberboard panels that did not require this additional bracing have been produced. Some fiberboard sheathing products can claim adequate structural shear strength, particularly if the proper nails and nail pattern are used.
Other contemporary producers of fiberboard building sheathing include International Bildrite (Bildrite structural), Georgia Pacific (Stedi-R & Stedi-R-structural), Knight Celotex (Celotex premium insulating), and Temple Inland (Temple fiber brace).
Fiberboard sheathing, also called black board, gray board, or buffalo board sheathing in some areas, is a fibrous material impregnated with a stabilizer and water repellant - asphalt on early versions of this material that we have found. While it's not easy to find and identify this material on a building wall unless indoor or outdoor demolition is being performed, you can spot the product in building attics on the gable-end walls.
The R-value of fiberboard sheathing is higher than plywood, gypsum board, etc, and is rated at about R 2.4 per inch (or about R 1.2 in more typical half-inch thickness with which it is applied. The board also reduces sound transmission into buildings.
[Click to enlarge any image]
Gypsum board has been used for non-structural wall sheathing and even roof sheathing on buildings for more than 50 years in North America alone.
Above is a row of 1940's buildings constructed at Stewart Air Force Base in Newburgh, New York, apparently as military housing. Some of these structures are still in use while others (foreground) are being demolished.
Originally a brick veneer covered the structure, behind which was this black paper-covered gypsum board sheathing.
An ongoing demolition project ca 2012-2014 has removed the brick veneer from several of these buildings, leaving the gypsum-board sheathing exposed to the weather.
Hand hewn beams, chopped and then sized with an adze and axe were used in North America from the 1600's into the late 1800's. Our photograph at above right shows adze cuts and axe cuts that are normally visible in the rough surface of hand hewn wood structural beams.
Timber frame construction initially used hand hewn beams, cut roughly rectangular by an adze and axe. Later beams were sawn manually or mechanically by a manually operated vertical pit saw, ultimately by machine-powered pit saws and circular saws. Timber framing using post and beam construction with mortise and tenon joint connections was used in Europe for at least 500 years before it was first employed in North America.
Our photo at above left shows typical roof framing on a Poughkeepsie home built ca 1790. Notice that there is no ridge board or ridge beam used, just a treenail-joined pair of numbered saw-cut rafters. The timber framing shown in our photograph at above left is from an 1875 Colonial home in Newburgh, NY. You can see this house at ARCHITECTURE, STYLE, & Building Age.
For details about post and beam construction methods see our full text article at Post & Beam Construction.
By 1650 a typical timber frame building used multiple bents and girt beams, may have been more than one story tall, and included an exterior made of horsehair-reinforced cement stuccoed over hand-split lath. Timber framing in North America continued until about 1920. (CF Reference due: Age of Barns, op. cit.)
Identifying Photographs of Homasote®, Celotex®, & Similar Fiberboard & Insulating Sheathing Board Products
Insulating building sheathing made by Homasote® is produced by the Homasote Company, a manufacturer in the U.S. in New Jersey, and similar fiber sheathing products have been used both as a sound barrier and for exterior sheathing on buildings.
Insulating board sheathing has been widely used on building exterior walls, under roofs, and against masonry foundations in finished basements.
Originally, Homasote produced sanded "agasote" sheets used in the roofs of passenger railroad cars, moving, in 1915, to automobile roofs, and in 1916 to construction products. Homasote was widely used for military barracks in both WWI and WWII and is still promoted for sound resistant sheathing and other applications.
Homasote and similar insulating building sheathing board products are still sold as a lower cost alternative to plywood or OSB for building sheathing. The product is used as structural paneling, insulation, concrete pouring forms, and expansion joints.
Our photos (above left and right) show close ups of Homasote-type insulating building sheathing board products, including a torn cross section showing the layered fibrous character of this material.
Where structural shear strength is needed by using the company's recommended ring-shanked nails in a specified nailing pattern. Homasote Co., the oldest manufacturer of building products from recycled materials in the United States, was founded by Eugenius Harvey Outerbridge as Agasote Millboard Company, and has been producing this material since 1909. In 1936 the company changed its name to its best known product, Homasote.
Our photographs below show Celotex® insulating board with an older Celotex fiberboard building sheathing board at left and a more recent Celotex insulating board product shown at below-right. Also see this close up of an older Celotex insulating sheathing board product.
Details about fiberboard sheathing products are at FIBERBOARD SHEATHING (separate article)
Antique Log Home Construction
(1640 - est U.S.): solid logs usually felled and prepared at or close to the building site, set on ground level, on flat stones on ground, or on a stone foundation, corners joined using various notch and overlap methods.
Our photo (left) shows traditional hand hewn logs and a log joint on a Norwegian cabin outside of Oslo.
Details about log home construction for old or traditional log cabins are discussed
Modern Pre-Cut Log Home Construction
Typical modern log homes use 6" or larger diameter factory milled logs that are cut to precise dimensions and whose design includes interlocking splines and gaskets to protect against leakage. In our photo (left) you can see the notches on the log bottoms and the log-end profile shows the raised splines on the top of each log.
See Home Buyers/Owners Guide to Log Homes for complete details about log home types, construction methods, inspection procedures, common defects.
See Slab Log Cabin Siding for a description of conventionally framed homes with a log-exterior.
Also see Log Home Construction for a brief description of this construction method.
Our complete list of log-home information, inspection, diagnosis, repair, construction, articles is at LOG HOME GUIDE
Questions & answers or comments about how to determine the age of building framing and sheathing materials, a step in determining the age of a building or of building components, systems, styles, and architectural design
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