Rot & Framing Repair

Framing repair covers rotted sill plates and joist ends, cracked or sagging joists, damaged studs, and joists cut by past renovations to make room for pipes or ducts. "Structural repairs or alterations" are on ottawa.ca's list of building permit projects, so ask the City before structural framing is replaced.

Under the Building Code, a hole in a floor, ceiling or roof joist is no larger than a quarter of its depth and at least 50 mm from the edges. A notch goes on the top of the joist, within half the joist depth of the bearing, and no deeper than a third of the depth, unless the joist is made deeper by the size of the cut. These rules are written for sawn lumber; for engineered joists, ask what the joist maker allows.

Moisture is the other cause. The Code has the ends of joists and beams that frame into masonry or concrete at or below ground level treated against decay or given a 12 mm air space. Untreated wood on concrete that touches the ground is separated by 0.05 mm polyethylene or Type S roll roofing, unless it sits at least 150 mm above the ground.

We found no Code rule on how much rotted wood must be cut out or how a joist is sistered, so ask how the repair will be done and whether it needs a design. Where subfloor is replaced, the minimum for plywood or O-2 OSB is 15.5 mm on joists at 400 mm and 18.5 mm at 600 mm.