Canadian Contractor

DMX Plastics Ltd.   

Ensuring that new basement floor finishes don’t lead to an old problem: mold

Canadian Contractor

Water can form underneath that new basement laminate flooring: from wicking up through the slab, or from condensation.

This is a Sponsored Post courtesy of DMX Plastics, Canadian manufacturers of the DMX 1-Step Underlayment system and the DMX AG Air Gap Membrane.

Why do so many Canadian basements have that distinctive musty smell?  Because mold feeds off of moisture and – particularly in Canada’s older homes, we just didn’t know enough about preventing basement moisture problems until our industry began to get a lot smarter in this area, and quite recently, too.

A lot of basements got their mold growths going during the first big basement renovation boom in Canadian history – the 1960s. As “rec rooms” became all the rage, and people started spending time in their basements for the first time, we saw an epidemic of interior finishes being attached onto basement walls and floors with very little knowledge of moisture trapping. (Think of the number of shag rugs that were placed on basement floor slabs, with maybe just regular carpet under padding. Or the number of hollow stud walls that were erected to finish basements, the voids just perfect breeding places for mold from the accumulating moisture.)

There are some 9-million residential basements in this country – and up to 40 per cent of them, according to studies from the CMCH and elsewhere – have moisture and mold problems. No surprise, given how sloppy we have been with the technology. Again, until recently.

Foundation wall leaks are the most common source of basement moisture issues.

But close behind those dig-it-up-outside-and-seal-the-leak situations, moisture gets into basements two more ways: it wicks through concrete walls and slabs, or it accumulates owing to condensation.

The solution to both moisture-wicking and condensation is to provide an impervious basement subfloor material if you are installing finished floors in a basement. Products such as DMX’s 1-Step Floor Underlayment can be used directly on basement slabs, underneath laminate or other finishing material. Impervious barrier products like this have multiple roles: they prevent the direct transmission of water, they result in the warmer final finishing materials, which reduces condensation. And they have sound-deadening qualities, too.

Dealing with a basement moisture problem, like all building envelope issues, means that you have to deal with the “whole house.” Exterior grading, eavestroughs, exterior foundation waterproofing, vapour barriers, insulation, ventilation, dehumidification, the proper venting of clothes dryers and bathroom fans, all are part of the solution, too.


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