Posts: 2,279
Threads: 454
Joined: Jul 2023
Reputation:
0
I have a little storage room on the first floor of my home. The walls are drywalled and I have a mold problem. I started tearing out drywall on the back wall and I found that there is a crawlspace area behind it. There is no type of vapor barrier or insultion in this room or on the walls. When I go to replace the drywall in there, how do I keep the moisture from that crawlspace area from damaging my drywall and letting mold into the room? Can I just put up a sheet of plastic between the crawl space area and the new drywall? Also, should I have that crawlspace insulated (I was thinking spray foam type)? It sits below my kitchen and our floor is always cold. My main goal is to keep moisture out of the crawlspace and the room. Any help is greatly appreciated.
Thanks,
Stavs
Posts: 24,633
Threads: 1,093
Joined: May 2025
Well, first I'd look at the crawlspace as potential room for a built in safe of some kind for valuables...
Failing that, I think a plastic vapor barrier is semi-standard.
Someone with more construction experience can probably give you a less wishy-washy answer than that.
Posts: 50,838
Threads: 670
Joined: Mar 2024
If I'm picturing it correctly (concrete walls?) the space needs venting, not isolation. Although there is a certain degree of moisture that weeps through concrete, so a concrete paint barrier might help.
If this is a basement, a dehumidifier helps with mold, but doesn't necessarily help to get rid of it once it is established in drywall and studs.
Posts: 26,414
Threads: 741
Joined: May 2025
Reputation:
0
Four steps:
1. If there is any standing water or muddy spots, you need to eliminate the source of water first (downspouts emptying right next to foundation?...bad grading around foundation?, etc)
2. Insulate the floor of the kitchen (i.e. the ceiling of the crawlspace). I suggest using the thickest rigid (i.e. styrofoam) insulation you can find, since it is highly effective and much more pleasant to deal with in a confined space than fiberglass. Just cut to fit between the joists with a drywall saw and jam it up against the floorboards...use a few nails driven sideways into the joists or perhaps some of those spring steel rods used for fiberglass insulation to hold it in place.
3. Vent the crawlspace to the outside somehow. You need at least two vents to get some airflow through there.
4. Place a vapor barrier (heavy polyethylene sheeting) on the crawlspace floor.
Posts: 8,225
Threads: 431
Joined: Jan 2009
Reputation:
0
Not a coal bin. Maybe a niche for a water heater or something like that... it looks like that might be a flue in the ceiling, in which case there may already be decent ventilation in there.
Posts: 50,838
Threads: 670
Joined: Mar 2024
Coal bin would have had a 18-36" access chute to gravity feed from a dump truck.
That looks more the size of an unfinished bulkhead access.
That's a concrete ceiling with a 4" hole the size of a drain waste pipe?
Or, possibly a stove pipe for a wood stove ?
Regardless;
Is there a concrete floor under that dirt on the floor ?
Why not just open the space up and use it ?
Posts: 2,279
Threads: 454
Joined: Jul 2023
Reputation:
0
I'll be honest that I'm scared to go in there....critters and stuff. I'm thinking I should insulate the ceiling as recommended. Should I just seal it up with polyetheline and then drywall it and be done? I cant imagine doing anything with that space.