Frequently asked questions

Most residential crawl spaces are finished in two to four days. Clean-out and any drainage work take longer than the liner itself, and a badly contaminated space needs remediation first.

It removes the conditions mould needs, which is moisture. Existing growth on joists usually has to be treated separately before the space is sealed, because sealing over it does not kill it.

Usually yes. A liner stops moisture coming up from the soil, but it does not remove what is already in the air or what enters when someone opens the hatch. Most systems in this climate need a dehumidifier to hold humidity below about 60 percent.

No, and anyone who says otherwise is selling one or the other. A barrier addresses ground moisture only. If humid outside air is the problem, open vents will keep bringing it in.

Building code minimum is thin, and thin liners tear the first time someone crawls over them. Most contractors here install something substantially heavier for anything meant to last.

If water pools under the house, yes. A liner over standing water traps it and hides it.

Away from the foundation, and far enough that it does not circle back. A discharge that ends beside the wall recycles the same water.

Colour does not identify a species and neither does a photo. If identification matters for a sale or a health concern, pay for a sample. For deciding whether to fix the moisture, it does not matter what species it is.

Not if the crawl space is still wet. Treat the growth and fix the moisture, or plan on doing it again.

Walls, if the space is sealed. Subfloor, only if it is going to stay vented. Doing both is usually a sign nobody decided which approach they were taking.

Under about 60 percent is the usual target. Sustained higher readings are what let mould establish on the framing.

Often, when it comes with a quote. Ask before scheduling, and get the answer in writing.