Watch for the following in roofs framed with trusses:
- Cut/damaged/altered trusses;
- Site-built (un-engineered) trusses (SE);
- Bottom chords should be clipped- not nailed- to interior walls;
- Installed plumb/near plumb;
- Over-panned (installed too far apart (standard is 24" on center);
- Too long or short
- Distortion from improper long-term storage;
- DO NOT identify missing bracing as a defect. Bracing is specified by the truss designer and requirements vary with the roof design. Some roof truss systems have little or no bracing.
Metal Connectors and their Fasteners:
- Fasteners for almost all single metal connectors will be minimum 10d nails with the number marked on the nailhead (not 8D).
- Fasteners for almost all double and triple metal connectors will be minimum 16d vinyl-coated checkerhead nails.
- When hangers do not support top chords, i-joists require web stiffeners to be installed.
Site-built trusses are identified by the use of plywood gussets to connect web members. Trusses that have obviously been built onsite are typically not engineered and may not be strong enough to support expected roof loads. Even if such roofs are common in the areas in which you work, recommend evaluation by a structural engineer.