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How to reduce humidity in sealed concrete cellar

Tyson T
2 months ago


We have a safe room in our basement that we've converted into a storage area and cellar. The room is solid concrete- floors, walls, ceiling and has one door. You access the safe room behind a trick bookshelf in our basement. I've ran into a moisture problem this winter. The temperature in the fall and winter months is a pretty consistent 50 degrees, but the humidity is fluctuating between 88-98%. Consequently, there is a musty smell and we've had a bit of mildew on some storage containers in there. In the 2 corners of the ceiling that are against the outside (as in they don't share a wall with the house), there was some visible condensation. I'm trying to figure out the most efficient and economical route to address this issue.

There is one vent in the room that has a pipe attached to it and the pipe sticks up outside the back of the house. The original owner had attached some ducting to a small dekstop fan and attached that to the vent hole. I recently stuck a box fan in the room to circulate some air, and replaced the small desk fan with a small ventilation fan used for grow tents to suck air from the safe room to the outside via that vent. It has a much higher cfm than the desk fan, but I have not noticed any significant change in the humidity levels doing this. Both fans have been running continuous for a week. The condensation on the ceiling corners are much improved though.

I have a standard dehumidifier coming in the next week to try out and I'll drain that straight into the floor drain in the room. Does anyone have any other suggestions on how to reduce the humidity levels in a room like this econimically? The room is roughly 1500cu/ft (14x14x7.5) I stained and sealed the concrete floors when we purchased the house, and I was curious about whether using a product like DryLok on the walls and ceiling would offer any help? I've ready using DryLok can sometimes make a humidity issue worse and I certainly don't want that in an already compromised room.

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