Laminate Flooring on Enclosed Deck

My uncle has a sunroom that is basically an enclosed deck. The floor is slatted deck boards, open to, and elevated from, the ground.

He wants to put a finished floor on there. What are the best options?

I suggested a polyethylene barrier over the deck, followed by rigid insulation, then possibly a plywood underlay and finally laminate flooring. Would that work?

Would cement backerboard be a better choice?

He received counsel from a flooring guy that laminate is a bad choice in that room because of the climatic changes (it's unheated and uninsulated). But if you can do laminate in a basement, why not in such a room? He'd insulate the floor...

A basement is very constant temperature, so there is very little expansion and contraction.

I would consider some kind of carpet. That is very tolerant of things that would damage laminate or other smooth finish floors.

Thanks, Bob. What's the best way to insulate the floor?

prashster said:

Thanks, Bob. What's the best way to insulate the floor?

Click to expand...

First, figure out how much thickness you can stand.

Then, I would used a layer of rigid foam, with waterproof facing on the top side or both sides. It needs to have a layer of material that will prevent punching through.

You can use foam padding under the carpet which will insulate some, if you want that kind of carpet. If you use a more casual carpet without padding, then the foam is the best insulation and you probably need 3/8" of decent plywood for underlayment. I would not rely on 1/4" luan to resist punching a chair leg through to the foam insulation.