Protection & treatments
Moisture coming up from below is the most common hidden reason new floors fail. Kitchener Prestige Flooring tests slabs and subfloors, then installs vapour barriers and moisture mitigation systems for homeowners, builders and commercial clients across Kitchener and Waterloo Region.
After more than 16 years and 1,700+ flooring jobs, we have replaced plenty of cupped hardwood, peeling vinyl and moldy carpet pad caused by moisture nobody measured. We specify barriers from test results, not guesswork.
Our crew is licensed, insured and WSIB covered. All barrier and mitigation work carries a written 1-year labour warranty.
Concrete is full of tiny pores that carry water vapour up from the ground. Put a floor on top without a barrier, and that vapour collects under it.
Wood cups and buckles. Vinyl adhesive softens and the planks lift or bubble. Carpet pad grows mould, and tile grout stays dark and damp.
These failures often appear months after installation, long after the floor is paid for. Because the cause is invisible, it is often blamed on the flooring product. We diagnose it first so your new floor does not become the next example.
Not every floor needs one, but these three situations almost always do.
Below-grade slabs sit against damp soil year round. Many Waterloo Region homes built before the 1990s have no polyethylene under the slab at all.
Every floor we install on a basement slab gets a barrier matched to the flooring, whether that is a sheet, an underlayment film or a moisture-tolerant adhesive.
Floors over crawl spaces and unheated garages pull moisture from below and lose heat. Bare dirt crawl spaces are especially damp.
A sealed ground cover and proper insulation protect the floor above and keep the space dry.
Additions, sunrooms and some bungalows have main floors poured directly on the ground. They behave like basement slabs and need the same care.
We never guess at moisture. Two tests give us the numbers we need.
Under the ASTM F2170 standard, we drill small holes to 40% of the slab depth, insert sensors and let them settle for 24 hours. The reading shows the humidity inside the slab.
Most flooring and adhesive makers publish a maximum reading, often between 75% and 95% depending on the product.
The ASTM F1869 test seals a dish of calcium chloride on the slab for 60 to 72 hours. The weight it gains shows how much moisture the slab releases.
Results are given in pounds per 1,000 square feet per 24 hours. Many products allow 3 to 5 pounds, while moisture-tolerant systems allow more.
We choose the barrier from the test results and the flooring going on top.
For new slabs and additions, a 10 mil polyethylene sheet goes over the compacted stone before the pour. Seams overlap and are taped, and edges are sealed at the walls.
It is the cheapest, most effective barrier there is, which is why we include it in every concrete floor installation.
For existing slabs that test too wet, we grind the surface and apply a two-part epoxy moisture mitigation system. It bonds to the concrete and blocks vapour at high emission rates.
It is the right answer before glue-down floors, which cannot sit on loose poly sheet. For above-floor protection against spills, see floor sealing and waterproofing.
Many floating floors use an underlayment with a film already attached. Over a dry slab, that film is often all you need.
We still tape the seams and run the film up the walls behind the baseboard. For engineered hardwood over concrete, this step protects the warranty.
A perm rating measures how much water vapour passes through a material. Lower numbers block more.
Basement slabs usually need a Class I barrier. Wood subfloors over a heated space need something more breathable, so moisture is not trapped in the wood.
Many older farmhouses and village homes across Woolwich, Wilmot and Wellesley townships sit over dirt or gravel crawl spaces. Moisture from that ground rises straight into the floor framing.
Encapsulation covers the ground and walls with a 10 to 20 mil reinforced liner, sealed at seams, piers and the sill. The space is then dehumidified or conditioned.
It protects the floor above, reduces musty smells and makes the house more comfortable. Rotted joists and sheathing found along the way are fixed through our subfloor repair and replacement service.
Typical 2026 ranges in Waterloo Region:
| Item | Typical cost |
|---|---|
| Slab moisture testing, per home | $150 to $350 |
| Polyethylene sheet barrier, installed | $0.30 to $0.75 per sq ft |
| Liquid moisture mitigation membrane | $3.00 to $7.00 per sq ft |
| Crawl space encapsulation | $3.00 to $8.00 per sq ft |
Compared with replacing a failed floor, a barrier is cheap insurance. All barrier work carries our 1-year labour warranty.
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FAQ
Straight answers to the questions we hear most. Still unsure? Call and ask.
Ask for a Free QuoteVisible signs include white powdery deposits, dark damp patches, a musty smell and adhesive that never fully cures. The only reliable answer is a test, either in-situ relative humidity probes or a calcium chloride test, compared to the flooring maker's limit.
Under a floating floor over a dry slab, a 6 mil polyethylene sheet with taped, overlapped seams is often exactly right. It is not a fix for a wet slab, and it cannot go under glue-down floors. Testing tells you which situation you are in.
Yes, over concrete. Engineered boards are more stable than solid, but moisture from the slab can still cup them. Floating installs get a polyethylene barrier, and glue-down installs use an adhesive with a built-in moisture membrane.
It depends on the flooring and adhesive. As a rough guide, many wood products need slab humidity at or below 75 to 80%, and many vinyl adhesives allow 85 to 95%.
Wood subfloors should read 12% or less. The manufacturer's number always wins.
Free estimate
Tell us about the floor. We will call to book a time, measure on site, check the subfloor and moisture, and leave you a written quote.
Prefer to talk it through first? Call and speak to a flooring specialist directly.
Kitchener Prestige Flooring
137 Glasgow St, Kitchener, ON N2M 5E3
Monday to Saturday: 7:00am to 9:30pm
Sunday: 9:00am to 9:00pm