2020 state of the art mold-free basement basement walls
May 18, 2020 8:47 AM   Subscribe

I saw a question in 2009 saying maybe cement walls might do the trick, but maybe not for this? What can I do to keep my walls safe when the floor gets wet?

My basement sometimes floods a bit. I managed to take care of the main issue so it wouldn't happen so often (make sure sump pump is ok, clear out tree root), but when the Chicago River is reversed there isn't much I can do.

Basically, the floor floods and the bottom of the walls get damp. Our floor is cement and I have the dehumidifier going. I'm trying to get the remediators in to clean up the floors. They should be ok soon.

However, every time this happens the drywall in the basement is damp for about 1 foot up, and that needs to be removed and replaced. Can I use the cement wall type to replace it? In 11 years, has a new material come out what would work well? How can I avoid replacing these walls again in the future?

Thank you.
posted by debgpi to Home & Garden (5 answers total) 2 users marked this as a favorite
Your drywall should not touch the floor. Would raising it up a half inch clear the water, or are we talking more than that?

You can hide the gap behind a baseboard.
posted by postel's law at 9:15 AM on May 18 [2 favorites]

The Journal of Light Construction has covered this, taking lessons from Hurricane Katrina. This article is [kinda] behind a paywall, but you might get a glimpse of what you need or just look at this image here.

Essentially, install drywall on the upper half of the wall, then a removable horizontal trim piece that laps over that drywall and a lower piece of drywall that is spaced several inches off the floor, with baseboard covering the bottom of that. You can get PVC baseboards too.

So then when the floor gets wet, the lower drywall ideally doesn't get wet until several inches of water. If it does, you pull the baseboard, remove the lower runs of drywall, let the studs dry out, then pop some new drywall on.

(You could also sub wainscoting for the lower drywall. You can get PVC wainscoting!)
posted by MonsieurBon at 10:30 AM on May 18 [10 favorites]

Oh, and don’t let the upper and lower drywall pieces touch each other. I’d probably also use PVC for the trim that covers that gap.
posted by MonsieurBon at 11:10 AM on May 18

Here we use waterproof drywall sheeting for wet areas - bathrooms etc (is this what you are talking about with cement wall type?). It will withstand damp/wet conditions without deteriorating. In your situation the paint may need re-doing, but even that may be avoidable by a good choice of paint/preparation.

Do you have a frame behind the sheeting, if there is timber battening it will not be enjoying the innundation, it would be worth replacing it with a galvanised batten at the same time.
posted by GeeEmm at 3:13 PM on May 18

What's behind the drywall? If it's wood, then you need to remove the panel anyway, so no reason to use fancier materials.

Better is to fasten foam board to the wall, then 3-coat stucco directly or single-layer over cement board. All of these materials can handle being wet and will dry quickly enough.
posted by flimflam at 4:54 PM on May 18

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