When finishing a basement floor to increase living space, should a vapor barrier be laid under flooring material?
I live in Oregon, somewhat damp environment, in an 90 year old house.
I get moisture moving up thru the basement floor. IE if I lay a stack of magazines on the floor, they wind up sticking to it. I have done as much rainwater diversion on the outside as I can.
I was thinking about installing a cork floor. If I lay down plastic under this will this cause me issues due to the moisture not being able to migrate upwards? Will water build up beneath the plastic vapor barrier?
Would it be better to use some other flooring, like tile or another vapor permeable material?
This would continue to allow the moisture to evaporate into the atmosphere.
I have tested for Radon and have no issues with that.
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Most cork flooring manufacturers will not recommend contact installation on a damp floor. You might be able to get away with an engineered floating floor over plastic, if this is what you have in mind check with the manufacturer's recommendations. Of course if you actually have liquid water on the basement floor rather just a slight humidity problem you'll have to fix that first. If you've truly done everything possible to keep water away on the outside and it's still damp, you'll need to install comprehensive water protection on the interior probably including a perimeter drain and sump pump.
Vincent,
You certainly need something more than a layer of polyethylene on top of your concrete.
1. If liquid water sometimes floods your basement, you need to install a French drain at the perimeter of the basement, connected to a sump, before proceeding.
2. If you're sure that liquid water never enters your basement, you have two choices: (a) Install a dimpled membrane like System Platon or Delta-FL under your finish flooring; or (b) Install a layer of XPS rigid foam on your concrete, followed by plywood subflooring (fastened through the foam to the concrete).