Walls are the part of the house people most want to insulate and the part where we most often say wait.
About 59% of Edmonton's housing was built before 1991, and in that stock the walls are the one assembly where getting it wrong is expensive, slow to show, and hidden behind drywall.
The honest sequence
Attics and rim joists are open, inspectable and low-risk. Walls are none of those things.
So the order that makes sense in an Edmonton house is: seal the attic penetrations, do the rim joist, deal with the basement - and treat the walls as a separate decision taken afterwards, on evidence. By the time those three are done, a lot of houses no longer have a comfort problem worth opening walls for.
That is not us talking ourselves out of work. It is the sequence that gives you the most comfort per dollar.
When walls genuinely make sense
During a renovation, while they are open. This is the moment. Sealing and insulating a wall cavity with the studs exposed costs a fraction of any other approach, and the installer can actually see what is in there. If you are re-siding or gutting a room, get the envelope specified before it closes up.
On new construction, where the decision is made at framing.
Where a specific wall is demonstrably the problem - a room that stays cold with a well-sealed attic and basement, usually an exposed corner or a wall over an unheated space.
The question to settle first
Edmonton's sustained cold drives moisture outward through walls all winter - a long, one-directional push rather than the back-and-forth of a chinook climate.
If your house already has a poly vapour barrier on the warm side, adding a second vapour-resistant layer inside the cavity can leave the assembly unable to dry in either direction. That is the failure that shows up years later as damaged sheathing.
So before anything is injected or sprayed into a wall, the installer should be able to tell you: what is already in that cavity, which way the wall dries, and where the new material sits relative to the existing barrier. If those answers are vague, do not proceed.
See vapour barrier and spray foam and when not to use spray foam.
Injecting into a closed wall
Filling an existing closed cavity is possible, and it is a genuinely different job from spraying an open one - different material behaviour, no visual confirmation of coverage, and no way to inspect the result afterwards.
It suits some houses and not others. Injecting spray foam into existing walls covers the trade-offs honestly.
What we do
We are a referral service. We do not install. We connect you with vetted installers - certification, insurance and WCB standing checked - and they quote directly.
No price without a site visit, and for walls we would rather someone looked before recommending anything at all.
Get a quote, and say whether the walls are open, about to be, or closed.
See also wall insulation province-wide and Edmonton basements.