What crawlspace encapsulation does
Encapsulation is about moisture control. A heavy-duty vapor barrier is installed across the crawlspace floor and up the walls, vents are sealed, and a dehumidifier keeps humidity low. The goal is to turn a damp, vented crawlspace into a clean, dry, semi-conditioned space. It stops moisture, mold, and musty odors at the source.
Encapsulation doesn't insulate by itself (though it can be paired with wall insulation). Its primary job is to keep water vapor and humid outside air out of the crawlspace — which protects the floor structure above and the air quality in your whole home.
What spray foam does
Spray foam is about insulation and air-sealing. Closed-cell spray foam applied to crawlspace walls and rim joists insulates (high R-value per inch) and creates an airtight barrier that stops drafts and stack effect. It doesn't manage bulk water on the floor, but it dramatically improves thermal performance and stops air leakage.
In a crawlspace, spray foam is typically applied to the walls and rim joists — not the floor (the vapor barrier handles the floor). It turns the crawlspace into a warm, semi-conditioned buffer that reduces heat loss from the floor above and protects plumbing from freezing.
Which do you need?
If your main problem is moisture — musty smells, mold, damp soil, high humidity — you need encapsulation first. Drying the space is the priority; insulation on top of a wet crawlspace traps moisture and makes mold worse.
If your main problem is cold floors and high heating bills with a relatively dry crawlspace, spray foam on the walls and rim joists is the higher-impact upgrade.
For most Ottawa homes, the best result comes from doing both: encapsulate the floor with a vapor barrier to control moisture, then insulate the walls and rim joists with closed-cell spray foam to control heat loss. This creates a fully conditioned crawlspace — dry, warm, and energy-efficient.
How they work together
The combination is the gold standard. The vapor barrier stops ground moisture; the spray foam stops heat loss and air leakage; the dehumidifier keeps humidity in check. Together they protect your floor structure, improve indoor air quality, warm the floors above, and lower energy bills. We assess your crawlspace and recommend the right sequence — moisture always comes first.