Damp proofing exposed foundation wall
user-1119003523
| Posted in General Questions on
I am residing my 140-year-old house and decided I’d like to insulate the exposed 30” of foundation wall with Comfortboard and a protective face. Unfortunately, the wall is made up of 8”x12” concrete blocks with irregular faces, up to 2” variation in the surface.
i assume I will have to parge them smooth with mortar if I want to damp proof them – I’m told mastics don’t deal with cracks well and I know a membrane is it out of the question.
Are there any other options I may not be aware of?
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Replies
That sounds like a good situation for an elastomeric membrane, either sprayed on or rolled on. This is one brand I've used a few times with good results: https://www.advancedcoatings.on.ca/products/residential/waterproofing-residential/rub-r-wall-residential-waterproofing. You might not even need to apply a parge coat. Some brands can be installed by a DIYer while others require manufacturer training.
What you linked doesn’t appear to be available in US markets except through the occasional contractor, it seems. There’s several off the shelf solutions at my local Menards, but I suspect I may not get what I need that way. Still, I’ll take a closer look at it.
Like I said, some products require manufacturer training. In fact I think the best ones do and are spray-applied. If you want true waterproofing, I wouldn't rely on something you buy at a big-box store and roll on yourself. If you do a local search for foundation waterproofing and ask about rubberized elastomeric membranes, or ask a few foundation contractors, you should be able to find a solution.
Another approach is to frame out a wall a couple of inches from the foundation and trap a sheet of foam between the walls.