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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
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

More Information

Building Framing & Sheathing Materials A Photo Guide to Types & Age of Framing Beams, Rafters, Studs, Lumber & Sheathing       How to identify types of building framing materials & use them to guess building age - How to identify types of roof sheathing or wall sheathing, Building framing and sheathing details can determine the age of of the structure, Building component age: construction materials, methods, including hardware, saw cuts, and other details can help determine when a building was constructed or when it was modified. FRAMING MATERIALS, Age, Types Dimensional Lumber ENGINEERED WOOD Products Hewn beams & planks HDO Plywood I-JOISTS, Wood Roof Floor Log construction LVL Laminated Veneer Lumber, Beams MDO Plywood PSL Lumber Sheathing, Gypsum board Sheathing Celotex Homasote & Other SHEATHING, OSB SHEATHING, Plywood SHEATHING, FOIL FACED - VENTS STRAW BALE CONSTRUCTION TRUSSES, Floor & Roof FRAMING METHODS, Age, Types - separate article Questions & Answers 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 References

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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.

Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.

Framing & Construction Materials as Indicators of Building Age

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.

See Framing Methods Age for the history and date ranges of various building framing methods. Also see Nails and Hardware, Age, Types and Saw Cuts, Tool Marks, Age of for additional building age clues likely to be available when examining building framing materials. Also see ARCHITECTURE & BUILDING COMPONENT ID.

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 left our photo illustrates a modern (21st century) post-and-beam construction using milled timbers but traditional mortise and tenon and treenail connectors. Engineered Cross-Laminated Timber (CLT) or Structural wood panels: laminated wood panels, often up to 6" thick x 30 ' in length, used in prefabricated wood building construction. (Also see I-Joists, LVL, etc. in the list below). An example of a large engineered wood panel structure is the nine-story Graphite Apartments, a residential tower built in London, and described by the New York Times in 2012. [26] The Times article described cross-laminated timber or CLT, developed in Europe inthe 1990's and a recent member of the engineerred wood family of structural materials. Thanks to Larry Olson [15]. In the U.S. CLT is to be produced by Innovative Timber Systems in Montana. [27] Log construction using logs, originally usually from or close to the building site, of various dimensions, thickness and length, chopped, dried, assembled at the building site: Log framing and both modern and antique log construction are discussed at Log Home Guide. Also see Antique & Old Log Cabins and Vertical Log Walls on Cabins & Homes. Hand hewn beams, chopped and then sized with an adze and axe. Adze cuts and axe cuts are normally visible in the rough surface of hand hewn wood structural beams. Our photo (left) shows modern post-and-beam construction - see Post & Beam Construction Historic dimensional lumber: full-sized 2"x4" (or larger 2 x n") wood framing materials - see Balloon Framing and see Platform Framing Modern dimensional lumber: wood framing wall studs 2x4's (3.5" x 1/5") and larger members (x" deep by 1.5" thick) - see Balloon Framing and see Platform Framing Tongue and groove wood subflooring, wall sheathing, roof sheathing - Hand split or rough hewn planks used for building structures - see Plank Houses Trusses, Floor - Engineered wood floor trusses (photo above right) such as I-Joists originally were constructed using a plywood web beginning in 1977, and modified by by Trus-Joist in 1969 to use laminated veneer lumber (LVL) and OSB-like laminated wood fiber web (our photo, above right) Trusses, Roof - Engineered factory built roof trusses - see TRUSSES, Floor & Roof I-Joists - details about wood I-Joists are at I-JOISTS, Wood Roof Floor Laminated beams such as GluLam™ (photo at above left) or microlam structural wood beams (Details about LVL are at LVL Laminated Veneer Lumber, Beams). Layers of wood are glued (laminated) together with heat, resin binder, and pressure to form a very strong structural member that can be produced in regular sizes and lengths. Unlike plywood or OSB, LVL lumber uses wood fragments that are all oriented in the same direction to produce very stiff beams that generally have greater span capacity than sawn lumber. GluLam produces laminated wood beams, timbers, I-joists, and other engineered wood products. Also see DEFINITIONS of ENGINEERED WOOD OSB LVL etc Oriented-strand board subflooring, wall sheathing, roof sheathing - see Age of Framing Materials-OSB. Details about OSB are at OSB - Oriented Strand Board. Also see DEFINITIONS of ENGINEERED WOOD OSB LVL etc PLYWOOD Roof, Wall, Floor Decks & Sheathing subfloors, wall sheathing, roof sheathing - see Age of Framing Materials-PLYWOOD Roof, Wall, Floor Decks & Sheathing and see FIRE RETARDANT PLYWOOD Details about plywood building materials are at PLYWOOD Roof, Wall, Floor Decks & Sheathing. Also see MDO Plywood and  HDO Plywood at DEFINITIONS of ENGINEERED WOOD OSB LVL etc

Cement Board & Fiber Cement Building Products

Asbestos-Cement Board & Fiberboard Products

Exterior Siding & Roofing Using Asbestos Cement included asbestos cement shingles, asbestos cement siding, corrugated asbestos-cement roofing.

See Asbestos Roofing Materials and ASBESTOS CEMENT SIDING

Other fiber cement materials used in construction included
TRANSITE PIPE AIR DUCTS
Transite Pipe Chimneys & Flues
Transite Pipe Water Supply Piping

Also see ASBESTOS IDENTIFICATION IN BUILDINGS and see SIDING MATERIALS, Age, Types

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

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.

The development of machine made nails that could be produced in high volume was critical to this change in construction methods. But even in the 1930's and 40's nails were a meaningful cost of construction. When our friend Paul Galow worked as an assistant to his uncle who built homes in Pennsylvania in the 1930's and 40's, his job was to salvage nails and hammer each bent one straight.

But by 1940 or earlier the finished size of most framing lumber products was less than the nominal size. A modern 2x4 is approximately 1 1/2" x 3 1/2" in cross section.

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 means 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. Or architects and engineers specify an engineered wood product such as a laminate-beam or wooden I-trusses or trusses where that strength is needed.

Engineered Wood Product Building Construction Materials History & Dates

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.

• Trusses, Floor - Engineered wood floor trusses (photo above right) such as I-Joists originally were constructed using a plywood web beginning in 1977, and modified by by Trus-Joist in 1969 to use laminated veneer lumber (LVL) and OSB-like laminated wood fiber web (our photo, above right). Details about wood floor trusses are at TRUSSES, Floor & Roof
• Trusses, Roof - Engineered factory built roof trusses - Details about wood and steel roof trusses are at TRUSSES, Floor & Roof
• I-Joists - details about wood I-Joists are at I-JOISTS, Wood Roof Floor
• Laminated beams such as GluLam™ (photo at above left) or microlam structural wood beams (Details about LVL are at LVL Laminated Veneer Lumber, Beams). Layers of wood are glued (laminated) together with heat, resin binder, and pressure to form a very strong structural member that can be produced in regular sizes and lengths.
  
  Unlike plywood or OSB, LVL lumber uses wood fragments that are all oriented in the same direction to produce very stiff beams that generally have greater span capacity than sawn lumber. GluLam produces laminated wood beams, timbers, I-joists, and other engineered wood products. Also see DEFINITIONS of ENGINEERED WOOD OSB LVL etc
• Oriented-strand board subflooring, wall sheathing, roof sheathing - see Age of Framing Materials-OSB. Details about OSB are at OSB - Oriented Strand Board. Also see DEFINITIONS of ENGINEERED WOOD OSB LVL etc
• PLYWOOD Roof, Wall, Floor Decks & Sheathing subfloors, wall sheathing, roof sheathing - see Age of Framing Materials -PLYWOOD Roof, Wall, Floor Decks & Sheathing and see FIRE RETARDANT PLYWOOD Also see MDO Plywood and  HDO Plywood at DEFINITIONS of ENGINEERED WOOD OSB LVL etc

Fiberboard Building Sheathing: Black board, grayboard, buffaloboard exterior sheathing

In addition to plywood, OSB, and gypsum board, impregnated fiberboard has been used as exterior building insulating sheathing in North America since at least 1909 (see our discussion of Homasote, below and see Masonite™ and other hardboard Sheet and Siding Building Materials). 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.

Gypsum board building exterior wall sheathing - history, description, age of use

Gypsum board has been used for non-structural wall and even roof sheathing on buildings (photo at left). On buildings where gypsum board was used to cover walls or roofing, for structural stiffness we expect to find either plywood or let-in bracing nailed at the corners of building walls. Initial versions of this product have not performed well on buildings where they might be exposed to dampness or leaks. We have found this material installed under asphalt roof shingles, hardboard siding, and other exterior siding materials. Gypsum board continues to be marketed as a less costly alternative to plywood or OSB building sheathing. These panels are intended for use under brick veneer and stucco exterior building wall finishes. Later versions of the material are called cementious board sheathing and can be expected to have been treated with water repellant chemicals.

Producers of gypsum panels used for building sheathing include Georgia Pacific Co. (Densglas gold™), US Gypsum Co. (Fiberock™), and National Gypsum Company (Gold bond™). Our photo (left) shows a closeup of gypsum sheathing board used on building exterior walls and on some roofs. Georgia Pacific's DensGlas™ exterior building sheathing includes this product description: "The product features a moisture-resistant core and enhanced fiberglass mats, instead of paper facings, to resist the effects of moisture exposure during and after construction. It is so weather-resistant that Georgia-Pacific backs it with a 12-Month Weather Exposure Limited Warranty. " The company indicates that contemporary gypsum board sheathing such as their DensGlas™ product is intended to serve as a building " substrate behind brick, siding, EIFS, stucco and other permanent claddings." Watch out: OPINION: unless your building is only expected to last 12-months, you should not leave gypsum board exposed to the weather. In fact few building sheathing products are intended to be left exposed to weather. For example, OSB sheathing board also deteriorates if it is repeatedly wet.

Hewn Beams & Pit-Sawn Planks as Construction Materials - Help in Determining Building Age

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.

Our photo-left, shows a hand-sawn pit-saw cut beam or plank.

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.)

• Saw cuts and tool marks and how they can be read as an aid in determining the age and method of construction of builidings are at Saw Cuts, Tool Marks, Age of.
• Also see Nails and Hardware, Age, Types

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 closeups 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 closeup of an older Celotex insulating sheathing board product.

Also see Fiberboard insulating sheathing or board sheathing products and see Masonite® hardboard siding products.

Log Home Construction Materials

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. Old or traditional log cabins are discussed at Antique & Old Log Cabins and at Vertical Log Walls on Cabins & Homes.

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.

Here is our complete list of log-home information, inspection, diagnosis, repair, construction, articles:

LOG HOME ENERGY EFFICIENCY
LOG HOME GUIDE
  Antique & Old Log Cabins
  Cracks, Checking or Splitting Beams & Log Homes
  Condensation & Moisture in Log Homes
  Energy Efficiency of Log Homes
  Leak Diagnosis & Cure for Log Houses
  Log Wall Height Changes
  R-VALUES & THERMAL MASS in LOG HOMES
  Sealants, Caulks, & Coatings for Log Homes
  Shrinkage In Log Home Walls
  Slab Log Cabin Siding
  Spline & Gasket Designs for Log Buildings
  Spline Gaps & Gasket Omissions
  Types of Log Houses - Log Choices
  Vertical Log Walls on Cabins & Homes
  Wall Insulation Values in Log Homes

Masonite™ and other hardboard Sheet and Siding Building Materials

(History & dates in process, contributions invited) Our photo (left) shows the back side of an early hardboard interior-use product labeled "Genuine4 Masonite Quartrboard".

OSB - Oriented Strand Board Roof and Wall Sheathing Materials

Details about the properties of OSB are at OSB - Oriented Strand Board. Also see DEFINITIONS of ENGINEERED WOOD OSB LVL etc. Excerpts are below.

Our photo (left) shows oriented strand roof decking (OSB) from the attic side, in new construction. Developed in the 1980's, oriented strand board is an engineered wood product in which strands and flakes of wood are cut from straight, low-knot small-diameter logs, usually aspen or white birch. What is the difference between waferboard and OSB? OSB is a modern wood product that developed from earlier 1970's "waferboard" product. In 1990 the Structural Board Association was formed. By 1996 there were 38 OSB producers in North America. Unlike waferboard whose composite wood chips were place randomly, an oriented strand board product is made from wood chips that are deliberately oriented with respect to one another to provide greater strength. See SHEATHING, OSB for more details and photo examples of OSB Oriented Strand Board sheathing use. CONTACT us to contribute photographs of waferboard or OSB.

Plywood Sheathing on Walls & Roofs: Use in Building Construction, History, Description, Identification

Details about plywood building materials are at PLYWOOD Roof, Wall, Floor Decks & Sheathing. Also see MDO Plywood and  HDO Plywood at DEFINITIONS of ENGINEERED WOOD OSB LVL etc. Excerpts are below.

PLYWOOD Roof, Wall, Floor Decks & Sheathing (1905 - present as a construction material in North America) is sheet material made of thin veneers of wood that are laid with wood grains in alternating direction, glued, heated, and pressed together.

Our photo (left) shows both fire-retardant plywood roof sheathing (left half of the photo and center top and bottom) and OSB roof sheathing (center of photo and right edges of photo).

While modern plywood products use a variety of glues, heat, and pressure to produce the product, plywood has been around at least since 3500 BC when a glued-veneer version was produced in Egypt. The rotary lathe (ca 1850) made modern plywood possible by cutting large sheets of wood from logs. The sheets are at right angles to one another and glued together using interior or exterior-rated structural adhesives. Interior plywood is generally glued with urea formaldehyde based glues; exterior plywood and marine plywood use phenolic formaldehyde glues and are water resistant.

Also see FIRE RETARDANT PLYWOOD.

Floor & Roof Truss Materials used in Building Construction

Details about wood roof and floor trusses are found at TRUSSES, Floor & Roof. Excerpts are below.

Wood Floor & Roof Truss Photos

Our photos show an attic view of modern roof trusses (above left) and floor trusses (above right).

Truss uplift, a cosmetic not a structural defect, is discussed separately at TRUSS UPLIFT, ROOF

Metal Floor & Roof Trusses

Details about metal roof and floor trusses are found at TRUSSES, Floor & Roof. Excerpts are below.

Steel roof trusses do not "rot" of course, but they too are vulnerable to damage from water, leaks, and rust.

Below our photo shows steel I-joists used in floor structures.

Also see I-JOISTS, Wood Roof Floor and see FRAMING METAL STUD PERFORMANCE

Welded Wire Sandwich Framing Panelized Construction

Welded-wire sandwich framing panels: polystyrene or polyurethane foam core insulation is surrounded by a welded-wire space frame.

(History & dates in process, contributions invited)

Frequently Asked Questions (FAQs) about building framing & sheathing materials

Question: Question about Homasote product from 1940s. Mold problems on gypsum board exterior building sheathing? Asbestos in exterior gypsum board sheathing products?

Was there a Homasote product used in the early 1940s on the exterior of houses that looks like sheet rock? How long does this last for? I

f it is still on the house, could it contain asbestos and/or contain mold due to lack of sunlight?

Was there "code" at some point that would have forced individuals who were to replace vinyl siding on the house over these boards to replace with proper products after a certain date? Thank you, K.B.C.

Reply: Properties of Homasote® type fiberboard compared with gypsum-based exterior wall & roof sheathing boards

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with sheathing, leaks, and mold or asbestos sources in buildings - the concerns you expressed. That said, here are some things to consider:

Homasote® fiberboard sheathing is a wood fiber product, not a gypsum or plasterboard product. However there were indeed gypsum-based sheathing board products used on buildings both as wall sheathing (under siding and over studs) as well as roof sheathing. Having inspected quite a few buildings that used this material, my OPINION is that it has proven surprisingly durable so long as it was kept dry. Wet the material can become soft, and also one might find mold growth on the paper backing of the gypsum board.

We describe these two different product types at Sheathing, Gypsum board and at Sheathing Celotex Homasote & Other - a section of FRAMING MATERIALS, Age, Types where we describe the history of building framing and sheathing materials.

Some Gypsum board and plaster board products indeed contain asbestos as does some joint compound

Indeed some gypsum--based drywall products did contain asbestos into the 1980's. I have not, however, tested nor seen test results specifically for exterior wall sheathing using that material. I suggest sending a small sample, a square inch would be plenty, to a certified asbestos testing lab - the cost should be less than $50. Do let me know what you find as the results will be helpful to other readers.

Even when gypsum board or plaster board did not itself contain asbestos, some joint compounds did contain that material right up into the 1980's. But used as an exterior sheathing, at the buildings I've seen, there was no top coating of joint compound and tape on this type of sheathing board (as there would be on drywall used for interior wall coverings).

Mold growth on gypsum board building sheathing?

About mold growth: the simple absence of light is not sufficient to cause problematic mold growth in building cavities. Water or high moisture would be a requirement for nearly all indoor mold contamination. And indeed I have found mold growth on paper backer on plaster-board exterior wall sheathing, in the wall cavity in buildings where there had been leaks into those spaces.

So if your home's walls were leaky (from ice dam leaks at the eaves, from leaks around windows or doors, from wind-blown rain penetrating damaged siding, etc) then there might be problematic mold growth on those surfaces - in the previously or currently wet areas. Whether or not this problem deserves investigation and remediation is not something one can decide without more detailed information.

See MOLD EXPERT, WHEN TO HIRE for help in deciding if in your particular case hiring a competent professional to inspect and test the building is justified.

Requirements to Remove Old Siding & Sheathing When Re-Siding a Building?

Finally, I've not found any national building code that requires a homeowner to replace one existing siding or wall sheathing material with another. The decision on siding-over existing surfaces vs. doing a (more expensive) tear-off depends on at least these considerations:

• The condition of the structure beneath the siding and sheathing. Siding and sheathing may need to be removed for structural repairs, for example.
• The condition of the siding and sheathing itself: very rough siding in poor condition forms a bad base over which to install new siding materials. The installer might simply nail furring strips over the existing walls, then install the new siding to the furring, or s/he might recommend a tear-off.
• Aesthetic/cosmetic concerns: when you build out a building's exterior walls with furring and new siding, the thicker wall will usually extend past existing window and door trim - giving the windows and doors a "sunken" look that you might not like. A solution is to build out the building trim at the same time. Some builders install wood or foam backer over the existing trim and wrap the new opening in aluminum so that it projects out past the new siding.

Watch out: be careful not to add multiple vapor barriers to a building wall. Installing an air and moisture resistant vapor-permeable housewrap should be fine however, and is required by some building codes and some product manufacturers.

...

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

• [1] Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
  • Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
  • Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
  • Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program.
    Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
  • The Home Reference Book, a reference & inspection report product for building owners & inspectors.
    Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
  • The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones.
    Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter inspectaehrb in the order payment page "Promo/Redemption" space.
  • The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
    Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
  • The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.
• America's Favorite Homes, mail-order catalogues as a guide to popular early 20th-century houses, Robert Schweitzer, Michael W.R. Davis, 1990, Wayne State University Press ISBN 0814320066 (may be available from Wayne State University Press)
• [4] American Plywood Association, APA, "Portland Manufacturing Company, No. 1, a series of monographs on the history of plywood manufacturing",Plywood Pioneers Association, 31 March, 1967, apawood.org 253-620-7400 APAWood.org
• [5] Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on Asbestos, Its Industrial Applications, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print).
• [6] Building Research Council, BRC, nee Small Homes Council, SHC, School of Architecture, University of Illinois at Urbana-Champaign, brc.arch.uiuc.edu. "The Small Homes Council (our original name) was organized in 1944 during the war at the request of the President of the University of Illinois to consider the role of the university in meeting the demand for housing in the United States. Soldiers would be coming home after the war and would be needing good low-cost housing. ...  In 1993, the Council became part of the School of Architecture, and since then has been known as the School of Architecture-Building Research Council. ... The Council's researchers answered many critical questions that would affect the quality of the nation's housing stock.
  • How could homes be designed and built more efficiently?
  • What kinds of construction and production techniques worked well and which did not?
  • How did people use different kinds of spaces in their homes?
  • What roles did community planning, zoning, and interior design play in how neighborhoods worked?
• [7] Georgia Pacific: information about DensGlas gypsum board building sheathing can be found at the company's website at gp.com/build/product.aspx?pid=4674
• [8] Homasote Co., 932 Lower Ferry Road, West Trenton, New Jersey 08628-024, U.S.A. 800-257-9491 homasote.com
• [9] "Hurricane Damage to Residential Structures: Risk and Mitigation", Jon K. Ayscue, The Johns Hopkins University, Baltimore, Maryland, published by the Natural Hazards Research and Applications Information Center, Institute of Behavioral Science, University of Colorado, November 1996. Abstract:
  "Property damage and loss from hurricanes have increased with population growth in coastal areas, and climatic factors point to more frequent and intense hurricanes in the future. This paper describes potential hurricane hazards from wind and water. Damage to residential structures from three recent intense hurricanes - Hugo, Andrew, and Iniki - shows that wind is responsible for greater property loss than water. The current state-of-the-art building technology is sufficient to reduce damage from hurricanes when properly applied, and this paper discusses those building techniques that can mitigate hurricane damage and recommends measures for mitigating future hurricane damage to homes." - online at www.colorado.edu/hazards/publications/wp/wp94/wp94.html
• [10] "Evaluating OSB for Coastal Roofs," Paul Fisette, Coastal Contractor, Winter 2005, online at coastalcontractor.net/pdf/2005/0501/0501eval.pdf . Fisette cites: "Jose Mitrani, a civil engineer and professor at Florida. International University in Miami, was ... Florida’s official damage assessment team. ... After Hurricane Andrew, Florida code advisers ruled OSB sheathing inferior to plywood
• [11] GluLam Structural Wood Products, U.S. GluLam Inc., 4245 W. 166th St., Oak Forest Il. 60452 - email: bevusg@aol.com, 708-535-6506
• [12] I-Joists: "The Evolution of Engineered Wood I-Joists", Paul Fisette, Building Materials and Wood Technology
  University of Massachusetts, Amherst, MA 01003, 2000 - see U. Mass online article at umass.edu/bmatwt/publications/articles/i_joist.html
• [13] Isham: "An Example of Colonial Paneling", Norman Morrison Isham, The Metropolitan Museum of Art Bulletin, Vol. 6, No. 5 (May, 1911), pp. 112-116, available by JSTOR.
• [14] Laminated Beams: Radial reinforcement of curved glue laminated wood beams with composite materials", Kasal, Bo and Heiduschke, Andreas, Forest Products Journal, 1 Jan 2004
• [15] Larry Olson, A-Quality Home & Building Inspections, LLC., Spokane WA 99224, Tel: 877-715-4520. private email, 6/5/2012 . Mr. Olson can be reached also by email to: lomo5202@gmail.com
• [16] OSB: "Evaluating OSB for Coastal Roofs," Paul Fisette, Coastal Contractor, Winter 2005, online at coastalcontractor.net/pdf/2005/0501/0501eval.pdf . Fisette cites: "Jose Mitrani, a civil engineer and professor at Florida. International University in Miami, was ... Florida’s official damage assessment team. ... After Hurricane Andrew, Florida code advisers ruled OSB sheathing inferior to plywood."
• [17] OSB: Timberco TECO is located at 2902 Terra Court, Sun Praire, WI 53590 USA, 608-837-2790. TECO provides a reference library of .PDF files that can be downloaded by consumers, homeowners, builders, and architects. The association refers to industry standards for oriented strand board OSB products as:
  • "DOC PS 2, Performance Standard for Wood-Based Structural-Use Panels. Certified to CSA 0325, Construction Sheathing, or CSA 0437, OSB and Waferboard, OSB is accepted in the National Building Code of Canada, certified to EN 300, Oriented Strand Boards and recognized for structural use in Europe and certified to meet the JAS standard for structural panels in Japan."
• [18] OSB: "Performance of Wood Shear Walls Sheathed with FRP-Reinforced OSB Panels", J. Struct. Engrg. Volume 132, Issue 1, pp. 153-163, Jan. 2006 provides a study on the development and structural testing of a hybrid sheathing panel designed to improve the lateral resistance of light wood-frame shear walls. "FRP" refers to fiber reinforced polymer material that was sandwiched between more conventional exterior OSB layers.
• [19] OSB - Universite Laval slides on the production of OSB are at xylo.sbf.ulaval.ca/osb/sld001.htm
• [20] Manufactured & Modular Homes: Modular Building Systems Association, MBSA, modularhousing.com, is a trade association promoting and providing links to contact modular builders in North America. Also see the Manufactured Home Owners Association, MHOAA, at www.mhoaa.us. The Manufactured Home Owners Association of America is a National Organization dedicated to the protection of the rights of all people living in Manufactured Housing in the United States.
• [21] Pergo AB, division of Perstorp AB, is a Swedish manufacturer or modern laminate flooring products. Information about the U.S. company can be found at http://www.pergo.com where we obtained historical data used in our discussion of the age of flooring materials in buildings.
• [22] Plank House Construction: webslog from plankhouse.wordpress.com/2009/01/25/plank-house-construction/ and where plank houses were built by native Americans, see
  Large 1:6 Scale Plank House Construction / P8094228, Photographer: Mike Meuser
  06/12/2007 documented at yurokplankhouse.com where scale model Museum quality Yurok Plank Houses are being sold to raise money for the Blue Creek - Ah Pah Traditional Yurok Village project.
• [23] Radiant barriers such as attached to OSB and plywood panels - see radiant barrier standard ASTM C1313, the California Title 24 Insulation Standards, and information provided by an industry site radiantguard.com
• [24] Scott C. LeMarr has provided his file of keys to decode Furnace and Water Heater Age from the data provided on the manufacturer's equipment labels. Mr. LeMarr is a professional home inspector, Certified Professional Inspector/President, MASTER Indoor Environmental Specialist (MIES). Vice President of Wisconsin NACHI. He and his company, Honest Home Inspections, LLC. can be reached at 262-424-5587 or by email to scott@honesthomeinspections.com
• [52] Weaver: Beaver Board and Upson Board: Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver, APT Bulletin, Vol. 28, No. 2/3 (1997), pp. 71-78, Association for Preservation Technology International (APT), available online at JSTOR.
• [26] "Wood That Reaches New Heights", Henry Fountain, The New York Times, 5 Juen 2012 p. D1, D4."Cross-laminated timber is hardy enough for high-rise buildings."
• [27] Innovative Timber Systems, Inc., Montana Sustainable Systems 1005 Baker Avenue, Suite G Whitefish, Montana 59937 406.261.1194 (M). Web search 6/5/12, Website: http://www.smartwoods.com/

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author. Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

• Building Failures, Diagnosis & Avoidance, 2d Ed., W.H. Ransom, E.& F. Spon, New York, 1987 ISBN 0-419-14270-3
• Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 ISBN-13: 978-0471331728
• Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
• Design of Wood Structures - ASD, Donald E. Breyer, Kenneth Fridley, Kelly Cobeen, David Pollock, McGraw Hill, 2003, ISBN-10: 0071379320, ISBN-13: 978-0071379328
  This book is an update of a long-established text dating from at least 1988 (DJF); Quoting:
  This book is gives a good grasp of seismic design for wood structures. Many of the examples especially near the end are good practice for the California PE Special Seismic Exam design questions. It gives a good grasp of how seismic forces move through a building and how to calculate those forces at various locations. THE CLASSIC TEXT ON WOOD DESIGN UPDATED TO INCLUDE THE LATEST CODES AND DATA. Reflects the most recent provisions of the 2003 International Building Code and 2001 National Design Specification for Wood Construction. Continuing the sterling standard set by earlier editions, this indispensable reference clearly explains the best wood design techniques for the safe handling of gravity and lateral loads. Carefully revised and updated to include the new 2003 International Building Code, ASCE 7-02 Minimum Design Loads for Buildings and Other Structures, the 2001 National Design Specification for Wood Construction, and the most recent Allowable Stress Design.
• Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
• Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
• Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting:
  A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
• Guide to Domestic Building Surveys, Jack Bower, Butterworth Architecture, London, 1988, ISBN 0-408-50000 X
• "Avoiding Foundation Failures," Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
• Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008) ISBN-10: 0471788368 ISBN-13: 978-0471788362
• Log Homes: Minimizing Air Leakage in Log Homes, U.S. Department of Energy
• Manual for the Inspection of Residential Wood Decks and Balconies, by Cheryl Anderson, Frank Woeste (Forest Products Society), & Joseph Loferski, October 2003, ISBN-13: 978-1892529343, $39.00 at Amazon.com or at the InspectAPediaBookstore
• R-Value of Wood, U.S. Department of Energy
• Straw Bale Home Design, U.S. Department of Energy provides information on strawbale home construction - original source at http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10350
• More Straw Bale Building: A Complete Guide to Designing and Building with Straw (Mother Earth News Wiser Living Series), Chris Magwood, Peter Mack, New Society Publishers (February 1, 2005), ISBN-10: 0865715181 ISBN-13: 978-0865715189 - Quoting:
  Straw bale houses are easy to build, affordable, super energy efficient, environmentally friendly, attractive, and can be designed to match the builder’s personal space needs, esthetics and budget. Despite mushrooming interest in the technique, however, most straw bale books focus on “selling” the dream of straw bale building, but don’t adequately address the most critical issues faced by bale house builders. Moreover, since many developments in this field are recent, few books are completely up to date with the latest techniques.
  More Straw Bale Building is designed to fill this gap. A completely rewritten edition of the 20,000-copy best--selling original, it leads the potential builder through the entire process of building a bale structure, tackling all the practical issues: finding and choosing bales; developing sound building plans; roofing; electrical, plumbing, and heating systems; building code compliance; and special concerns for builders in northern climates.
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