Framing near you

Framing jobs range from one partition to the whole structure of an addition, and all of them start with layout: walls, openings and floors must land where the drawings put them, line up with what's above and below, and leave room for services.

How far a joist or rafter can reach depends on the species and grade of the wood, its depth, how closely the members are spaced and the load they carry, including snow on a roof. Part 9 of the National Building Code of Canada, the model that provincial codes are built on, includes span tables for sawn-lumber joists, rafters and beams in ordinary houses. Provinces adopt the model code on their own schedule and sometimes with changes, so the framer and the permit reviewer work from the edition in force where you live.

Engineered products cover what the generic tables don't. I-joists, laminated veneer lumber and other manufactured beams are straighter and more consistent than sawn lumber and can span farther, but they're sized from the manufacturer's literature or by a designer or engineer. Each product also comes with its own rules on where holes may be cut, how it must bear on its supports and what blocking it needs. Once a beam replaces a bearing wall, carries a concentrated load or supports a new storey, sizing it is a professional's job.

Light-gauge steel studs are a common alternative to wood for partitions and basement walls. Part 9 of the model code covers sheet-steel studs only in non-loadbearing walls, interior or exterior; steel framing that carries loads falls outside those prescriptive rules and has to be designed.

Framing lumber can arrive wetter than it will be once the house is heated, especially after sitting outside through rain or snow. As it dries, wood shrinks, far more across its width than along its length, so deep floor systems and built-up headers move the most. Studs framed wet can twist or bow, fasteners can push out through the drywall, and gaps can open at the tops of walls and around stair openings.

Careful framers keep lumber off the ground and under cover, set aside boards that are already crooked or soaked, and give the frame time to dry before insulation, vapour barrier and drywall go on. Some check doubtful boards with a moisture meter. On an addition framed through a wet spring or fall, running the heat and a dehumidifier before the walls are closed in is worth the delay.

When framing is part of a permitted project, it has to be inspected before it disappears. The City of Toronto lists structural framing among the required inspection stages for houses, requested once framing is complete, including the rough-in of plumbing and HVAC, with insulation and vapour barrier inspected at a later stage. The city warns that anything covered before it passes inspection will have to be uncovered. Other municipalities use similar stages, so ask your permit office for its list at the start of the job.

The City of Toronto lists adding or removing walls, new or enlarged window and door openings, and additions among the work that needs a building permit, while finishing a basement with no structural alterations, new plumbing or additional unit is on its list of exemptions. Rules differ between municipalities, so check before framing starts.

Structural framing starts on paper. A beam replacing a bearing wall, a new opening in an exterior wall, a second storey or a change to the roof is designed by an engineer or a qualified designer, and it's never a do-it-yourself job. In Ontario, you can confirm an engineer's licence in the Professional Engineers Ontario directory of practitioners; in Quebec, the Ordre des ingénieurs du Québec publishes a directory of its members. In Quebec, the framer also needs an RBQ licence covering the work, such as subclass 6.1 for wood structures.

Any of these is a reason to have the structure assessed, by a structural engineer when the cause isn't obvious, before anyone jacks, shims or reinforces it.