Taking Subslab Insulation to 11

We dropped in on Manny and Anderson of Hardcore Renos to see how their first new build was progressing; very well thank you!

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Shervin laying all on the table helping to weigh the various energy upgrade options for the build. These guys are serious builders who want the best for their client and have invested in a planning process and have set targets for testing the home’s performance. In the end the homeowner wins.

 

We’ve known for years that heat escapes in all directions but its been difficult to convince builders and home owners to invest in sub-slab insulation. Of course, with the rise in popularity of radiant in-floor heating for the basement, insulating the slab is minimum code. We say it’s just common sense.

On this job site though, we saw something different, kinda like Nigel’s amp going to 11 in Spinal Tap. This house had sub-slab insulation WITH a THERMAL BREAK at the edge! I should have figured it was sprayed by Rich Krechowicz of CallRich Eco Services Inc his crew executed the job flawlessly.

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Photo 1: The beige colour above the basement slab is spray foam. If you look closely, you will notice the foam tapers from 2.5″ thick on the wall and feathered up to nothing.

A close-up detail of the previous photo shows the foam thickness between poured concrete wall and slab.

Photo 2: A close-up detail of the Photo 1 shows the foam thickness between poured concrete wall and slab.

I spoke to Mr. Krechowicz recently and he agrees “The concept of using spray foam is relatively unknown, so we don’t have these jobs too often.  The thermal break is so important and it is a detail that is mostly ignored or overlooked by contractors.” and I completely agree.

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The drawing shows the continuous insulation under the slab and around edge to insulated wall. Source: Building Science Info-513: Slab Edge Insulation. Click above for link.

The loss at slab edge is significant and is more obvious in wintertime when snow accumulates along the foundation wall. Mr. Krechowicz says “At my house I have a non-thermal break in the part of the house that is slab on grade, and you can see the melting of snow along the perimeter.” The cobbler’s shoes…

Krechowicz goes on to say “Another benefit to using spray foam is that it makes the job of securing radiant floor tubing a breeze, as the staples can be attached directly to the foam.”

For a great article on the topic, check out the Journal of Light Construction’s Insulating a Slab With Spray Foam by Mike Pindle, Jan 2010.

In an earlier post, I blogged about the potential for spray foam to go off ratio which brings me to the last point about spray foam. The person pulling the trigger needs experience and has to have a solid understanding of building science in order to do their job properly.

 

 

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