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 Mobile ViewSTRUCTURAL INSPECTIONS & DEFECTS ADVANCED INSPECTION METHODS AGE of a BUILDING - how to determine ARCHITECTURE & BUILDING COMPONENT ID BARK SIDE DOWN on DECKS, TRIM, STEPS BASEMENT WATERPROOFING BEST CONSTRUCTION PRACTICES GUIDE BRICK FOUNDATIONS & WALLS BRICK STRUCTURAL WALL Loose Bulged Brick Thermal Expansion Cracking BRICK VENEER WALL Loose, Bulged BRICK WALL DRAINAGE WEEP HOLES BUCKLED FOUNDATIONS due to INSULATION? BUILDING SAFETY HAZARDS GUIDE BUILDING SETTLEMENT CHIMNEY CHASE Construction & Defects CHIMNEY INSPECTION DIAGNOSIS REPAIR COLUMNS & POSTS, DEFECTS CONCRETE FOUNDATIONS CONCRETE FOUNDATIONS, PRE-CAST Cracks, Checking or Splitting Beams & Log Homes CRAWL SPACES DECK & PORCH CONSTRUCTION DECK COLLAPSE Case Study DECK FINISHES COATINGS PRESERVATIVES DECK FLASHING LEAKS, ROT Case Study DECKS, ROOFTOP CONSTRUCTION DEBRIS STAINING on ROOFS DEFINITIONS of Mobile Home, Doublewide, Modular, Panelized DEFINITIONS of ENGINEERED WOOD OSB LVL etc MDO Plywood HDO Plywood I-JOISTS, Wood Roof Floor LVL Laminated Veneer Lumber, Beams OSB - Oriented Strand Board PLYWOOD Roof, Wall, Floor Decks & Sheathing PSL Lumber DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE DISASTER BUILDING INSPECTION & REPAIR SAFEY EARTHQUAKE DAMAGED FOUNDATIONS ENERGY SAVINGS in BUILDINGS ENGINEERED WOOD Flooring ENGINEERED WOOD Products FIRE DAMAGE vs MOLD DAMAGE FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FLOODS IN BUILDINGS-mold FLOOR, ENGINEERED WOOD & LAMINATES FLOOR FRAMING & SUBFLOOR for TILE FLOOR TYPES & DEFECTS FLOOR TILE ASBESTOS IDENTIFICATION FLOOR TILE HISTORY & INGREDIENTS FOOTING & FOUNDATION DRAINS FOOTINGS EXPOSED, Repair Methods FOUNDATION BULGE or LEAN MEASUREMENTS FOUNDATION CONSTRUCTION TYPES FOUNDATION CONTRACTORS, ENGINEERS FOUNDATION CRACKS & DAMAGE GUIDE FOUNDATION FAILURES by TYPE & MATERIAL FOUNDATION FAILURES by MOVEMENT TYPE FOUNDATION INSPECTION METHODS FOUNDATION INSULATION OPTIONS FOUNDATION MATERIALS, Age, Types FOUNDATION REPAIR METHODS FOUNDATION WATERPROOFING FRAMING DAMAGE, INSPECTION, REPAIR FRAMING DETAILS for BETTER INSULATION FRAMING DETAILS for DOUBLE WALL HOUSES FRAMING CONNECTORS & JOIST HANGERS FRAMING FASTENERS, NAILS, SCREWS, & HIDDEN FRAMING & SUBFLOOR for TILE FRAMING MATERIALS, Age, Types Dimensional Lumber ENGINEERED WOOD Products Hewn beams & planks Log construction SHEATHING, FIBERBOARD Sheathing, Gypsum board Sheathing Homasote & Other Board SHEATHING, OSB SHEATHING, Plywood SHEATHING, FOIL FACED - VENTS STRAW BALE CONSTRUCTION TRUSSES, Floor & Roof FRAMING METAL STUD PERFORMANCE FRAMING METHODS, Age, Types FRAMING SIZE & Spacing, Age, Types FRAMING TABLES, SPANS for DECKS FRENCH DRAINS FROST HEAVES, FOUNDATION, SLAB FRT PLYWOOD GALVANIC SCALE & METAL CORROSION GLUES ADHESIVES, EXTERIOR CONSTRUCTION GRADING & SITE WORK, EXTERIOR GUTTERS & DOWNSPOUTS HOUSE PARTS, DEFINITIONS HOUSEWRAP INSTALLATION DETAILS ICE DAM PREVENTION I-JOISTS, Wood Roof Floor INSULATION IDENTIFICATION GUIDE INSULATION INSPECTION & IMPROVEMENT LEAD POISONING HAZARDS GUIDE LEED GREEN BUILDING CERTIFICATION LOG HOME GUIDE LVL Laminated Veneer Lumber, Beams MOBILE HOMES, DOUBLEWIDES, TRAILERS MODULAR HOME CONSTRUCTION MOISTURE CONTROL in BUILDINGS NOISE / SOUND DIAGNOSIS & CURE OSB - Oriented Strand Board PANELIZED CONSTRUCTION PLASTER BULGES & PILLOWS PLASTER, LOOSE FALL HAZARDS PLYWOOD Roof, Wall, Floor Decks & Sheathing PORCH CONSTRUCTION & SCREENING PRE-CUT & KIT HOMES Preservative-Treated Framing Lumber RAILINGS, DECK & PORCH RAILINGS, STAIRWAY RETAINING WALL DESIGNS, TYPES, DAMAGE RETAINING WALL GUARD RAILINGS ROT, FUNGUS, TERMITES ROT, TIMBER FRAME SEARS KIT HOUSES SEPTIC & CESSPOOL SAFETY SHEATHING, FIBERBOARD SHEATHING, Gypsum board SHEATHING Homasote & Other Board SHEATHING, OSB SHEATHING, Plywood SHEATHING, FOIL FACED - VENTS SIDING, Sheathing Identification - Photo Guide SINKHOLES, WARNING SIGNS SINKING BUILDINGS SLAB CRACK EVALUATION SLAB CRACK REPAIR Splits in Structural Wood Beams STAIN & BIODETERIORATION AGENT CATALOG STAINS on BUILDINGS - QUICK GUIDE STAIN DIAGNOSIS on BUILDING EXTERIORS STAIRS, RAILINGS, LANDINGS, RAMPS STONE CLEANING METHODS STONE FOUNDATIONS STONE VENEER WALLS STRAW BALE CONSTRUCTION STRESS SKIN INSULATED PANELS STUCCO WAll FAILURES DUE TO WEATHER STUCCO WALL METHODS & INSTALLATION STUCCO OVER FOAM INSULATION STUCCO PAINT FAILURES SUMP PUMPS GUIDE SWEATING (CONDENSATION) on PIPES, TANKS TERMITES, ROT THERMAL EXPANSION of MATERIALS THERMAL MASS in BUILDINGS TRIM, EXTERIOR CHOICES, INSTALLATION TRUSS UPLIFT, ROOF TRUSSES, Floor & Roof VAPOR BARRIERS & CONDENSATION in BUILDINGS VENTILATION in buildings VINYL Siding or PLASTIC Window ODORS in buildings VINYL CHLORIDE HEALTH INFO WATER BARRIERS, EXTERIOR BUILDING WATER ENTRY in BUILDINGS WIND ENERGY SYSTEMS WIND TURBINES & LIGHTNING WIND WASHING INSULATION At EAVES WINDOWS & DOORS, Age, Types WINTERIZE A BUILDING WOOD FOUNDATIONS More Information |
This article defines and illustrates plywood building products used in roof and wall sheathing and in floor construction. InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers nor with topics or services discussed at this website.Also see fire retardant plywood information at FRT PLYWOOD. OSB - oriented strand board "plywood" like products are discussed separately at SHEATHING, OSB. This article series describes wood products used in construction including engineered lumber, OSB, and Plywood products. Our page top photo shows a stack of nominal half-inch plywood sheathing (actual 15/32" in thickness) stacked at a Home Depot® building supply store. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. Definition & Characteristics of Plywood
Our photo (left) shows 1/2-inch CDX plywood installed as exterior wall sheathing on a home being constructed in Minneapolis, Minnesota. Plywood sheets are named according to the sheet thickness, the quality of its exterior or exposed veneers (A = clear, no knots, C/D - construction grade, etc), and its thickness. Plywood products are also selected for interior or exterior use based on the weather resistance of the glues used to glue the veneers together (exterior plywood uses exterior glues), and finally on the condition of interior veneers or plies of wood. Plywood used for floor sheathing or underlayment beneath carpeting, for example, is selected without interior voids so that someone's shoe-heel won't puncture through a clear top veneer of wood into a hidden void below. History & Age of Plywood Building ProductsAs we also discuss at FRAMING MATERIALS, Age, Types and at age of SHEATHING, Plywood:
Our photo (left) shows how a small section of damaged plywood roof sheathing was repaired. 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 furniture industry has had a long history of gluing thin fine-wood veneers to a cheaper wooden base - a process similar to the production of plywood itself. The invention of the rotary lathe (ca 1850) by Immanuel Nobel (1801 - 1872) is what made modern plywood possible by permitting manufacturers to cut large thin (but thicker than wood veneers) sheets of wood from logs. The wood sheets are placed at right angles to one another and glued together.
Our plywood roof sheathing photo (left) illustrates 1960's era 1/2-inch roof sheathing plywood that was being removed during a building expansion project. The properties of plywood, including its tolerance to weather exposure (marine plywood) depend on the glues and finishes used. Both softwood and hardwoods are used in plywoods, and fine wood veneer finishes are also available (for furniture use). The first plywood made in the Western U.S. was produced by the Portland Manufacturing Company in Oregon in 1905, a company founded four years earlier by Gustav A. Carlson, F.S. Doernbecher, and M.L. Holbrook. Peter Autzen bought out Doernbecher and Holbrook. It was Autzen's son, Thomas, who made key progress solving problems with bonding the veneers together.
Their plywood was exhibited at the 1905 Worlds' Fair in Portland, Oregon. Interestingly, the first exhibition of plywood as a building product in the Northwest was in a log structure, the Forestry Building in Portland, OR where it was displayed until that building burned in 1964. The stained plywood roof sheathing (left) was discovered during a home renovation project in which a flat roof was to be torn off for an addition. In 1924 plywood sales were still primarily to door producers, but by 1928 the company had increased production and plywood was being used in automobile bodies. In that year the Pacific Coast Plywood Manufacturers, Inc. (PCPM)was formed jointly with Elliot Bay Mill Co. (Seattle), Walton Veneer Co. (Everett WA), and Washington Veneer Co. (Olympia WA). But PCPM was dissolved after the 1929 Stock Market crash. The appeal and success of plywood as a building material are based on quite a few factors including increased construction speed (consider nailing up 4x8 sheets of plywood versus individual tongue and groove exterior building sheathing or roofing), product uniformity and strength, and the reduction of waste compared with cutting sheathing boards out of logs. Also see FIRE RETARDANT PLYWOOD. Definition & Characteristics of MDO Plywood"MDO" plywood (Medium Density Overlay) is constructed of a core of overlapping veneers of wood, but with a surface layer of medium density fiber. The resulting product has a smooth surface. MDO plywood can be used once as a concrete form material, but should not be re-used for that purpose. See TRIM, EXTERIOR CHOICES, INSTALLATION for a discussion of use of MDO plywood for use on building soffits. Definition & Characteristics of HDO Plywood"HDO" (High Density Overlay) plywood is similar to MDO Plywood described just above. HDO plywood also is constructed wit a core of overlapping wood veneers, but instead of using a medium density fiber for its external surfaces, HDO plywood uses a high-density fiber exterior. HDO plywood products, having a harder exterior surface, can be re-used several time for concrete forms. APA (The Engineered Wood Association) provides an HDO/MDO Plywood Product Guide that offers details about these products. The design and content found at InspectAPedia.com® are © Copyright protected, All Rights Reserved. Contents of this website may not be copied in any form. Our main website topics listed at page left and page top provide in-depth, un-biased, expert information on building defect inspection, diagnosis, & repair. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. DEFINITIONS of Mobile Home, Doublewide, Modular, Panelized
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