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STRUCTURAL INSPECTIONS & DEFECTS
ARCHITECTURE & BUILDING COMPONENT ID
CHIMNEY INSPECTION DIAGNOSIS REPAIR
COLUMNS & POSTS, DEFECTS
CONNECTORS, FASTENERS, TIES
DECK & PORCH CONSTRUCTION
DEFINITIONS of Mobile Home, Doublewide, Modular, Panelized
DEFINITIONS of ENGINEERED WOOD OSB LVL etc
DISASTER BUILDING INSPECTION & REPAIR
EARTHQUAKE DAMAGED FOUNDATIONS
FIRE DAMAGE vs MOLD DAMAGE
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FOOTING & FOUNDATION DRAINS
FOUNDATION CRACKS & DAMAGE GUIDE
FRAMING DAMAGE, INSPECTION, REPAIR
GRADING, DRAINAGE & SITE WORK
HOUSE PARTS, DEFINITIONS
INSECT INFESTATION / DAMAGE
KIT HOMES, Aladdin, Sears, Wards, Others
LOG HOME GUIDE
MOBILE HOMES, DOUBLEWIDES, TRAILERS
MODULAR HOME CONSTRUCTION
MOISTURE CONTROL in BUILDINGS
PORCH CONSTRUCTION & SCREENING
PRE-CUT & KIT HOMES
RETAINING WALL DESIGNS, TYPES, DAMAGE
ROT, FUNGUS, INSECT DAMAGE
SINKHOLES, WARNING SIGNS
STAIRS, RAILINGS, LANDINGS, RAMPS
STRAW BALE CONSTRUCTION
STRESS SKIN INSULATED PANELS
STRUCTURAL WOOD ASSESSMENT
TIMBER FRAMING, ROT
TRUSSES, Floor & Roof
WATER ENTRY in BUILDINGS
This article defines "wood I-Joists" and illustrates the uses and installation of wood I-Joists used in residential building floor and roof construction. This article series describes wood products used in construction including engineered lumber, OSB, and Plywood products. Also see FRAMING CONNECTORS & JOIST HANGERS for a discussion of special fasteners used when framing with wood I-joists.
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Our photo (below left) illustrates wood I-joists used in construction of building floors and roofs. You will observe that the center web of the I-joist is constructed of OSB sheathing material that we illustrated just above. Our second photo (below right) shows common lumber markings found on the solid wood top and bottom chords of wood I-joists. [Click any image to see an enlarged, detailed version]
Engineered wood floor trusses (photos above and below) 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 (shown in photos above left and below in combination with a steel beam).
Improper location or size of holes, notches, or even removal of the center web can cause substantial weakening of the structure and are violations of both the manufacturer's instructions and building codes.
See STRUCTURE, ROOF DEFECTS LIST for details.
Below our photos of I-joists used to support a building floor illustrate how the builder avoided most cuts in the i-joist webs: flex duct and plumbing were laid out to move between I-joists rather than through them, and where an HVAC duct trunk line had to run at right angles to the I-joists the builder suspended it below the I-joists.
This was a much better solution than we found at a different job where the builder removed entire sections of I-joist web to run large rectangular HVAC ducts!
Our wood I-joist photo at above right illustrates the use of doubled or paired wood I-joists and special steel connectors (I-Joist hangers) designed to support doubled I-joists where they abut a girder or beam.
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Frequently Asked Questions (FAQs) about I-joists
Questions & answers or comments about selecting, specifying, & constructing with & defect inspections of wood I-Joists for building floors & roofs.
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