Foam insulation around foundation with above-grade vapor barrier
Mcsmarto
| Posted in Plans Review on
I am buying a house and at the base of the house is a thick gray rubber/plastic covering. I’m being told it is a vapor barrier to protect the foam from UV rays. The barrier is loosely tacked and looks terrible (in my opinion). I asked why it was better installed, I was told this is the only way since there’s no way to attach to the foam. I’m afraid of moisture getting in and the look. Can you give me any advice?
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A photo would be very helpful. If you can also find out the name of the product, we might be able to provide more accurate comments. If you are hiring a home inspector as a part of the purchase process (you should), he/she might also be able to provide a good opinion, having seen the product and the house.
Thank you in advance for your assistance!
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You could probably remove it and replace with stucco. Perhaps synthetic - but I've had zero problems with real fiber stucco in Michigan.
McSmarto,
I would also be certain to have the inspector search for evidence of rodent and or insect invasion of the foam. A loose covering over foam is like offering free apartments to many things you don't want in residence. I would also ask for more details on how the foam was attached to the foundation, how far down the wall it goes, and water management details for all of it. If these answers are not satisfactory, best to plan on needing remedial work in the future.
If you do choose to go ahead with the house, I would suggest looking at skirting materials used on mobile homes or synthetic fascia materials made for decks. Both will be somewhat wavey looking without proper support, which is your first stated issue with the foam. I used Grace products on my basement foam insulation to encapsulate the whole wall from rim board to the footing. I did have design details worked out that allowed me to hang 1/2" steam shower rated Hardiboard in a way that excludes rodents and does not allow water to soak the board over time. Not approved, I admit. It was a bit tedious to install and detail, but at least I have created the appearance of a normal concrete "bottom" to the house.
I don't think stucco would serve you well given the constraints already mentioned by you. The biggest issue will be water retention and freeze thaw if you are in a northern location, and termites an additional moisture source in the south.
Here is some additional photos. Thank you.
Yes, that's ugly. And water will get behind it because there's no flashing on top and because it sticks out past the siding in a few places. The water probably (probably) won't cause any damage, as it should be able to drain out at the bottom of the wall into the foundation drains, if you have them. The builder also messed up the hardiplank siding pretty badly. Those scratches won't wash off if that's the Colorplus siding, so you will have to live with them.
If this is the level of pride the builder takes in his work, you might want to question the rest of the job. Have you had an independent inspection? Now is the time to find out as much as you can. It's better knowing about the defects before they become your problem.
As far as the protection board, it's ugly, but it will provide some protection to the foam. There are better ways to do this.
I did have an independent inspection and they suggested "looking"at it but not that it was a "major" issue. I certainly agree with you and it does cause me some concern. Thank you for your input.