Advanced Basement Systems Case Studies: Fixing an Improperly Insulated Crawl Space in London, On

Monday, November 4th, 2019 by Ben Bates


Years ago, these London homeowners were tired of musty smells in the home, the cold floors and the high heating and cooling bills. They knew the problem was coming from their crawl space.

They did what they believed best at the time and installed:

  • Rigid wall insulation to some exterior walls

  • Fibreglass insulation to other exterior walls

  • Stuffed fibreglass insulation in between the floor joists above and “sealed” it in with a plastic sheet

  • Layed down plastic sheeting on the floor of the crawl space

This is something we’ve seen time and again, and unfortunately, their efforts and money spent were a complete waste. 

Why are we so often called out to fix a crawl space when they’ve already attempted to “fix” the problem? 

Because these “fixes” simply do not work



Crawl spaces, just like basements, are directly below our living space. While there may not be a full set of stairs inside a home to access a crawl space, this area should be treated just as a basement - completely sealed off from the outside environment. 

Sealing or “encapsulating” a crawl space involves several steps - none which can be skipped or “skimped on”. Here’s our process:

  • We ensure the crawl space has the proper drainage in place. We address any plumbing or foundation leaks. Depending on the area, a home may require extra drainage installed and/or a sump pump specifically designed for crawl spaces.

  • We remove debris, including any moisture-laden fibreglass insulation, flimsy plastic sheeting, useless rigid insulation and mouldy cardboard. 

  • We measure and install our super heavy duty CleanSpace® vapor barrier. CleanSpace is a 20-mil reinforced polymer liner that's offered with a 25-year warranty against rips and tears. 

  • We often apply spray foam to the exterior walls or the header area in the crawl space. This helps keep the space comfortable regardless of the season. The CleanSpace barrier is then sealed to the spray foam. 

  • We seal the access areas with an airtight cover and seal unnecessary vents. This is the final step to ensure that the outside air stays where it belongs - outside! 

  • Often, crawl spaces are excessively humid and naturally damp, so to help condition the air and remove the humidity, we install a low-maintenance, energy-efficient dehumidifier which is specifically designed to work in crawl spaces. 

And this is exactly what we did for these London homeowners. Now they can enjoy 4 season comfort in their healthier home!


Project Summary

Inspector: Adam

Foreman: Justin

About the author
Ben Bates lives in the Chatham-Kent area and has been involved in the basement, crawl space and foundation industry since 2008. He has a passion for improving homes the right way and knows what it takes to waterproof, encapsulate or stabilize homes in Ontario. He assists with over 900 projects per year.

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Our Locations:

Advanced Basement Systems
23576 Prince Albert Road
Chatham, ON N7M 5J7

Advanced Basement Systems
199 Exeter Rd Unit E
London, ON N6L 1A4
Coverage Area: Southwestern Ontario