What do I use to replace basement wall coating?

September 9, 2009 11:39 AM

My old house's basement walls are deteriorating and need attention. But, I'm just not sure how to prep them and what to use to re-coat them. Also, should I be worried about moisture problems? See pictures here

My house was built in the 20's in the midwest. This is my first house, and I'm not much of a handyman. But, I do care about my home and want to keep it as well maintained as possible. My current project is my basement, which is in much need of attention. See pictures here. It appears to have some kind of coating over the bricks. There are several areas where the coating is crumbling and efflorescence (I believe) is present. The walls themselves are pretty straight, and are not bowing in any way. The bricks seem solid and don't appear to be crumbling.

When we moved in, there was some water leakage coming from one corner during heavy rains. Not enough to cover the floor, but enough to see it run to the drain. Luckily, that was an easy fix (a gutter that ran along that edge of the house needed replacement). Now, it is rare to see any water in the basement, even during flooding rains. But, should I still worry about moisture problems based on these pics? Should I hire a professional to inspect the walls?

I'm just clueless as to what I should use to re-coat the walls. I'm guessing that I need to scrape and remove the current coating that is falling apart. Then recoat with plaster maybe? I just want to use the right product to avoid water problems. From what I've read, it's possible that the wrong product could trap moisture and cause the bricks themselves to crumble. What should I use? Please advise.

posted by Swede78 to home & garden (9 answers total)

It's hard to tell from the pictures, but are your walls plaster-covered brick currently, or is it painted brick? If your moisture problem is pretty much taken care of, which it sounds like it is, and you just need to re-paint the brick walls, I recommend Drylok paint. Use a wire brush to clean off any peeling paint, and wash with bleach before painting if you're worried there might be mold. Set up a dehumidifier and air everything out as much as possible beforehand if the walls might still be damp.
posted by LolaGeek at 12:11 PM on September 9, 2009

Looks like just peeling paint in most places. That could've been caused by previous moisture problems or age. There's almost always some moisture in basements, unless they've been waterproofed from the outside. Interior waterproofing is much less effective than exterior. Is it especially humid in your basement?

The important thing to figure out is whether the brick is in good shape or not. If the brick is crumbling, then you have problems, and should consult a professional. If not, drylock or plastering should give you a nice finish.
posted by electroboy at 12:23 PM on September 9, 2009

One way to tell if there's moisture (according to "Ask This Old House") is to duct tape a nice big square of clear plastic to the wall and let it sit there for a while (Say a week or more). If water collects on the inside of the plastic, water is getting in through your foundation. If there's water on the outside of the plastic, there's a moisture problem in the basement.
posted by drezdn at 12:24 PM on September 9, 2009 [1 favorite]

Thanks for the feedback so far.

LolaGeek,
I believe it's currently plaster, due to the thickness and gloppy look in places. As for the moisture... it doesn't leak water onto the floor, but should I be worried that the walls look like this because of a moisture issue in the walls themselves?

electroboy,
No, it's not unusally humid. It seems slightly more humid than the rest of the house. Is there a way I check the brick condition myself?

drezdn,
I will give that tip a try.
posted by Swede78 at 12:53 PM on September 9, 2009

It's a skim coat of mortar over the bricks, called parging. You can wire brush, scrape and remove all the loose bits. Fill the bigger craters with mortar mix. Then paint with something like Drylock.
posted by fixedgear at 1:26 PM on September 9, 2009

Is there a way I check the brick condition myself?

Poke it with a screwdriver (not gouge, just like you're checking for rotten wood). If it crumbles like chalk, that's trouble. If it's only a few bricks, you might be able to have them replaced, but that's really a job for a professional.
posted by electroboy at 1:29 PM on September 9, 2009

Just personal experience from my own home.

Water tends to migrate from the surrounding soil into the comparatively drier basement. It carries dissolved minerals through the bricks to the inside. It also flakes the paint off. You can patch and paint the walls with something like Drylok and that'll probably be fine unless you plan to finish the basement with drywall etc. If thats the case, you need to waterproof it from the outside.
posted by bonobothegreat at 4:45 PM on September 9, 2009 [1 favorite]

Well, if the house was built in 1920, it could have been lime washed at some point. My father (who would be 92 now) mixed up some white powder and buttermilk and painted the basement walls just like his grandfather taught him. It lasted 30+ years, only giving in when the basement was flooded, and then it just flaked off where the water came through. Or, it could be paint, esp oil as oil will bubble and flake off if moisture comes in behind it. I agree that taping down a piece of plastic over the worst bits is a good start to see whether you have moisture, esp in the fall or after spring thaw when you're most likely to have damp. I'd take a wire brush to it (wear glasses as that stuff bounces) then paint it with a water seal made for basements. Check the outside of the house where the foundation meets the earth. Look for cracks where rain water can run down the outside of the house. If you find any, mix up some concrete patch and fill them, making the concrete slant away from the house. Your peeling whatever it is could be a leftover from ages ago or moisture seepage. You won't know until you've seen what's under the plastic after a week on the wall.
posted by x46 at 9:09 PM on September 9, 2009

Thanks for all the replies. I tried poking several bricks with a screwdriver, and the they didn't crumble at all. They are like rocks, not even the smallest chips came off. So, that's a good sign. I think I'll do as a few people suggested... scrape the walls and paint with Drylok. I feel much more confident with this decision now. Thanks again.
posted by Swede78 at 9:17 AM on September 15, 2009