Can an older BC house be made safer in an earthquake, and does it need a permit?

Question

Accepted Answer

An older wood-frame house can be strengthened, most often where it sits on its foundation, and a structural engineer is who assesses it; the work usually needs a building permit. A house built to an older code isn't automatically unsafe, but an older wood-frame house's commonest weak points are under the first floor, where in past earthquakes houses slid off their foundations or the short walls between foundation and floor folded. Strengthening those is what most house retrofits are. For a buyer the questions are whether it's been done, under a permit, and what the insurer makes of it. Look up the address or PID on PlaceDossier to see the record for that lot. Older isn't the same as unsafe: The building code has had seismic design since the 1950s, and a building built to older provisions isn't automatically inadequate: its condition, materials and how its parts are connected decide its risk. Older buildings can be retrofitted to perform better, and a qualified structural engineer is who assesses a building and recommends upgrades (the Province's fact sheet on seismic design in the BC Building Code). Where older houses fail: The most common weak points of an older wood-frame house are under the first floor: a foundation that is missing, broken up or in poor condition under the outside walls; walls not anchored to the foundation, or anchored poorly; and the short wall between the foundation and the first floor (a pony or cripple wall) not braced with structural panels. Large openings, such as a garage door or picture window, also weaken a wall (the City of Seattle's Home Earthquake Retrofit booklet, written for the same Cascadia earthquakes BC faces). What a retrofit usually is: That booklet's three tasks: anchor the sill plate to the foundation wall, sheathe the short walls with wood structural panels, and tie those walls to the floor above and the sill below with metal framing clips, or the floor joists straight to the sill where there's no short wall. It says each task is needed, as partly retrofitted homes did poorly in California's earthquakes. A house on a slab, on a hillside, with a room over a garage, or with a brick chimney is a case for an engineer (our reading). Water heaters and gas: PreparedBC's guide says to strap water heaters snugly to the wall and, if needed, have a licensed gas contractor fit a flexible gas line, and to secure tall furniture, fridges, washers and dryers. A gas line is gas work under a permit (see electrical and gas permits). Permits: A retrofit alters the structure, so it usually needs a building permit: the District of Saanich, for one, requires one to alter or reconstruct an existing building (its permit questions page). Ask the building department whether it wants engineered drawings or accepts a standard plan for this house (our reading). Does other work force an upgrade?: When a building is altered, renovated or repaired, or its use changes, its level of life safety and building performance must not be decreased below what already exists (BC Building Code 2024, Division A, Sentence 1.1.1.2 (1), as Building Code Appeal Board decision 1982 quotes it). That stops work making a house weaker; it doesn't by itself require bringing an older house up to today's seismic design, unless a local bylaw does (our reading). The City of Vancouver has its own building by-law, which we haven't read. Insurance: Earthquake damage isn't covered by a standard home policy; it's optional cover bought separately, where an insurer offers it (the Insurance Bureau of Canada's coverage page), and PreparedBC's guide points to the Insurance Bureau for earthquake insurance. Ask an insurer whether it covers this house, at what deductible, and whether a retrofit changes its terms; a strata building is insured by the strata (see strata insurance). What it means for a buyer: Ask whether the house has been bolted or braced, by whom and under which permit, and look for anchor bolts or plates along the sill in the crawlspace or basement. A home inspector can say what they see; only a structural engineer can say how the house would fare (our reading).

Can an older BC house be made safer in an earthquake, and does it need a permit?

What the answer means

Before you buy: who to ask