Concrete basement wall issue – Ideas needed
I have had a small woodworking shop in the basement of my home for years. I set it up with a dust controlled environment that isolates it from the forced air heating system that serves the rest of the house. This allowed me to putter away in the shop during the cold Midwest winters. The poured concrete basement wall surface was of good quality. It was tight and smooth with a painted surface making easy to clean off the saw dust from time to time.
We have recently moved to a newer home in the area and I would like to do a similar setup in the unfinished area of the new basement. The problem is this; The surface of the poured concrete basement wall is a much lower quality than our previous home. There are pits and pockets everywhere that would trap dust. Add to that, the issue of occasional wall condensation moisture eventually turning it into a crusty mess. Apparently the bar has been lowered for concrete wall construction quality in recent years. It would be quite easy to install a gypsum board “drywall” surface attached to furring strips or 2×4 framing, but I would prefer to allow the any condensation on the basement walls to dry unhindered by additional building materials that could trap moisture and start the mold and mildew processes (as I’ve experienced in another previous house). I’d prefer to stay away from attachment of wood framing products that would absorb moisture and plastic sheeting that would trap it. Ideally, I would like to find a concrete surface treatment of some kind that’s thick enough to smooth the pits and gouges, but I have my doubts about products like that staying firmly attached over time. Any product I’ve ever used to repair concrete has eventually failed.
Any and all construction ideas and material product tips are welcome!
Replies
It seems to me that a thick masonry paint would solve most of your problems, though you could instead skim coat the wall with some sort of masonry product.
Probably best to acid wash the wall first, to remove efflorescence. For skim coating I'd recommend tile thinset -- it's not real pretty (dark color), but it adheres well and develops a smooth finish. Most other products are less predictable.
Your condensation is being caused by large temperature differentials between your foundation wall and your inside space and can be excaserbated by excessive moisture being transmitted through your concrete wall. Think of holding a glass mug of a cold beverage on a warm day. Where's all that moisture (condensation) coming from? Not from the glass or what's being held inside the glass. It's coming from the micro-environment right around the cold glass. The air around it is being cooled to the point that the dew point is being reached (cooler air has less ability to hold moisture) and moisture precipitates out in the form of condensation.
Anyhow, letting all that moisture attempt to equilabrate into your shop is generally not a good thing. I'd be interested to know when your condensation seems the worst (guessing the beginning of the heating season) and what the R.H. is in your shop generally.
My recommendation(s) areo:
1. First check to see that you have adequate foundation drainage and damp proofing around your house.
2. Install a moisture barrier on the inside face of your foundation (Keridi if you can afford it), then insulate your wall to code.
3. Frame and hang 1/2" A/C plywood (screwed) in your shop space. This way you can hang things most anywhere you want and if you need to get in the wall to modify utilities it's only a matter of removing what on the wall and unscrewing the panel(s).
You Said Newer...
... not new so my first thought that all the wood & stuff in a newly-constructed house needs time to equilibrate to a more reasonable moisture content... by whch time (a year?) any potential for a condensation issue may resolve itself.
You know offhand what the relative humidity is over a period of time in that basement?
Is there any sort of insulation + moisture-proofing on the foundation's outside? (I moved into a full-basemented, ~ 35 year-old ranch house about this time last year, surprised to learn moisture-proofing poured foundations of any kind wasn't / isn't standard practice in the area.)
How long have you been in this place and would you consider the general level of detailing makes it a reasonably tight structure, air-exchange wise?
I'd be prepared to parge the interior wall surfaces too were I in your position. I like the suggestion of using thinset, a product I've used before though not for this purpose.
If you feel insulation would be beneficial it's worth doing a search here for pertinent info on current best practices to mitigate problems with moisture and subsequent risk of mold.
If you can find a stucco guy who is a true "plasterer" he can make your wall smooth as drywall with a stucco product. We did this with a room we built and it came out great.
Just be sure the wall is clean and paint some link on it.
B
What is this crusty mess you describe your wall being?