The rim joist is the band of framing sitting on top of the foundation wall, running the full perimeter of the house. It is a small target with an outsized effect on how a house feels.
With about 59% of Edmonton's housing built before 1991, most homes in this city have a rim joist that was filled with a batt and never sealed.
The suite problem
Edmonton has a great many basement suites, and the rim joist matters more when someone lives down there.
In an unfinished basement a leaky rim joist is a draught and a heating cost. In an occupied suite it is a comfort complaint, a cold-floor complaint, and often a condensation complaint - because now there is a person down there generating moisture through cooking, washing and simply breathing, in a space with cold surfaces around the perimeter.
Warm humid interior air reaching cold wood and cold concrete condenses. In a sealed-up finished basement, that happens behind the finishes where nobody sees it until there is a smell or a stain.
Sealing the rim joist properly removes both the air path and, at adequate depth, keeps the condensing surface inside the foam rather than on the framing.
If your basement is a suite or about to become one, do this before the ceiling and walls are closed in. Afterwards it means opening them up again.
Sustained cold, sustained loss
Edmonton's winter does not swing the way southern Alberta's does. It gets cold and holds.
That matters for a leak: heat loss accumulates in proportion to how long the temperature difference lasts. A rim joist gap here is not costing you during a few cold snaps - it is costing you continuously for months. The payback on sealing it is correspondingly short.
It also means the stack effect runs hard and steadily. Warm air escapes at the top of the house all winter, and something has to replace it. That replacement air comes in low, through the rim joist, and the colder and longer the season the more forcefully it does so.
Older stock, more variation
Edmonton's age range means the assemblies vary. Some houses have a straightforward accessible band; others have been added to, re-framed, or have had services run through the cavity over decades.
That is a reason to have someone look rather than quote from a floor plan. It is also a reason foam suits the job - it fills irregular, penetrated cavities that no batt can be cut to match.
Practicalities
Pricing follows access more than area. An open basement ceiling is quick work; a crowded or partly finished one is not. Clear what you reasonably can before the crew arrives.
What we do
We are a referral service. We do not install. We connect you with vetted installers - certification, insurance and WCB standing checked - who quote directly.
No price without a site visit. Get a quote, and mention whether the basement is finished, unfinished, or a suite.
See also rim joist insulation province-wide and basement spray foam in Edmonton.