Saturation & Frost Outside Above Grade Foundation

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Posted by: from Ottawa
12/13/2019 at 6:41:01 PM

Hi everyone,

We moved into a newly built house 13 months ago and when Winter hit, we started getting freezing/frost on the outside of the exterior wall.

The parged portion is poured concrete and the brick portion is the framed section.

Concrete below grade has exterior rigid foam. Concrete above grade has rigid foam on interior + fiberglass insulation + vapor barrier. Framed portion has wrap, rigid foam, fiberglass insulation and vapor barrier.

After consulting a few people, they came to the conclusion that it was the concrete releasing moisture it still retained after being poured and freezing. It's been 18 months since the concrete was poured (poured in May/June). It's happening again this year now that winter has started.

The base of the interior of the garage wall on this side becomes saturated/wet to the touch and freezes/frosts up. Running a ventilation fan in the garage has helped with this. The saturation starts at the back of the garage and wicks towards the front. The back of the garage is where the first step down on the foundation.

Under the garage is unexcavated, after the first step down is a finished basement room.

Using an infrared camera inside the house in the room that's in the lower right, there's nothing that looks too out of the ordinary behind the wall.

I'm not sure where this moisture is coming from. The exterior infrared image seems darkest where the basement room is finished. The unexcavated isn't as frozen. The first image (wall.jpg) is from last year, the remaining ones are from today. It's not as bad as last year yet, but still early on. We're at about 34% RH indoors.

I'm not sure what to do / how to source the issue, but would love to know what's going on and hopefully solve it. Has anyone seen this happen / have any ideas?

I'm also trying to figure out when it happens it's possible that the saturation happens when it gets a bit more mild out and then wicks up. It was hovering between just above freezing and just below freezing the past 24 hours after a fairly good cold snap. I looked up the historical weather from last year when I took that photo and it looks like the same. This could be coincidental, but in case it helps.

Thanks in advance

Saturation & Frost Outside Above Grade Foundation
Saturation & Frost Outside Above Grade Foundation
Saturation & Frost Outside Above Grade Foundation
Saturation & Frost Outside Above Grade Foundation
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Gsfg in Hamilton
Date/Time12/14/2019 at 5:57:20 PM

You are still under the builder's warranty the first thing to do that will be to contact them and have them fixed the problem.

Please take into considerations builders have a tendency not to fix problems related to their slacks or cities cutting them brakes ...

FYI any work you have done they may blame it on the issue

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Date/Time12/15/2019 at 1:26:35 PM

Hi Brian

This clearly looks like a moisture build up

problem behind you brick work. There is a 1"

air space behind your bricks for proper air flow. You must have little weeper holes approx. every 3 to 4' along the bottom where the bricks meet the parging. Where the bricks step down , there must be a little weeper hole for air flow , unfortunately it does not look like there is

from your photos. You could try to drill a couple of weeper holes between the horizontal bricks. The bottom part of your hole can be slightly angled as to allow any moisture to come out. You probably only require one hole on those short horz. step down areas. You may not see any difference

for a while.

good luck

User Icon
Date/Time12/22/2019 at 8:48:40 PM

Hi Brian,

Definitely an air issue.

You simply have warm air from the interior meeting cold air on the exterior causing frost build up. I would think there is a lack in "thermal break". Maybe spray foam the interior of all affected areas.

Bottom line....frost does not build up without warm / cold air mixture.

Best of luck....

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