Before you finish your basement: 7 things to check

Most basement problems are cheaper to solve before the drywall goes up. These are the things worth checking first.

1. Moisture and cracks

Look for damp spots, stains or cracks on the walls and floor, and seal visible cracks. Finishing over a moisture problem hides it until it becomes mould.

2. Grading and downspouts

The ground should slope away from the house, especially near the foundation. EPCOR recommends downspout extensions that carry water 1.5–2 m away from the house.

3. Radon

Health Canada recommends testing every home for radon, for at least 3 months, on the lowest level you use regularly. The guideline is 200 Bq/m³. If your level is higher, it's easier to plan mitigation before the basement is finished.

4. Bedroom windows

A basement bedroom needs a window with at least 0.35 m² of clear opening and no side under 380 mm. If your windows are small, plan for enlarging them now.

5. Ceiling height, beams and ducts

Low beams and ducts decide where rooms and bulkheads go. If you're thinking about a legal suite, the minimum is 1.95 m in living spaces and 1.85 m under beams and ducts.

6. Plumbing rough-ins and the backwater valve

Check whether you have bathroom rough-ins and where they are. It's also the time to add a backwater valve if your home was built before 1989. Rebates exist in Edmonton and Strathcona County.

7. Furnace room and alarms

Fuel-fired appliances must be enclosed in their own room with combustion air. Smoke alarms must be hardwired and interconnected, with one in every bedroom, and homes with a fuel-burning appliance or attached garage need CO alarms near the bedrooms.

Next: plans and permits

Once those checks are done, you can plan the work. A building permit application usually includes a basement floor plan with the use and size of each room, window and door locations and sizes, and a cross-section of the foundation wall. Foundation walls have to be insulated to the level the code sets for your area, with the vapour barrier on the warm side, and foam insulation has to be covered by a thermal barrier such as drywall.

In Alberta, the homeowner is ultimately responsible for making sure the necessary permits are in place before work starts, so ask who will apply for them before you sign anything.