Do you need a subfloor over insulated concrete?

Question

I'm having a house built, and I was discussing the floor in the basement with the builder. I thought I was going to use LVP over a subfloor, but the builder says they no longer put subfloors over concrete because the concrete is insulated at the bottom and sides, and protected by poly under the insulation.

The builder also does not like LVP over concrete because of the amount of self-leveling required, leading to additional cost.

Do I need a subfloor?

My concerns are moisture and the feel of the floor. I'm not worried about the headspace, and I won't be considering carpet as I have allergies.

Other questions on the site are about old houses, where they would not have insulation and barrier under the concrete.

Answer 1

Unless the concrete is poured poorly and full of lumps there is no reason why LVP cannot be over a concrete floor.

You can use a thin underlayment pad that will provide some extra insulation and a bit of noise abatement, as well as an additional vapor barrier.