View Full Version : basement bathroom and utility room floor insulation

12-24-2011, 01:03 PM
My basement is big (1600sqft). It is open space and bare to concrete wall and floor now. we have a bathroom there and plan to have a utility room as well. The gas boiler and hot water tank are in that area already. I added French drain around the wall and a sump pump last winter in case the 500yr flooding comes earlier. I have put two floor drains (one in bathroom and one in utility area) and three cleanouts with the French drain system to make sure water will have a good place to go if any.

I will follow suggestions from experts here to finish the basement. For the floor, i have a bathroom and a planned utility room, and also have floor drains and cleanouts on the floor. how should I handle them?

The floor will be insulated like this: 6mil ploy + 1" XPS foam board + 3/4 plywood.

1. utility room: I plan to have a separated utility room; seal poured concrete wall and floor with XYPEY. Because the pipes for air, water and gas have been there already, it is hard to do insulation in that portion. I lean to have no insulation on the wall and floor for that utility room.

2. bathroom: should I insulate the bathroom floor as other rooms?

3. floor drain and French drain cleanouts: should I make those floor drain and cleanouts available after the insulation? if yes, that means the insulation is nor sealed properly. If no, ...

What's your advice?

12-24-2011, 01:11 PM
What is the purpose of the 6mil?

12-24-2011, 06:35 PM
What is the purpose of the 6mil?
vapor barrier, I think.

12-27-2011, 08:54 AM
With an inch of XPS on the floor and a sealed slab the 6 mil poly isn't essential, but it doesn't hurt.

DO make the drains & cleanouts accessible. The exposed surface area that would be exposing (and then not vapor sealed) is very small and of no consequence. Concentrate on air-sealing- infiltration from the outside is a far larger source of moisture than a few square feet of exposure to sumps & drains.