How To Install Rigid Foam Insulation Under Floor

The first step is to build the floor joist or to strip back the floor until you can see the joist.

How to install rigid foam insulation under floor.

There are two ways to handle insulating concrete floors. Step 1 build the floors. Instead of installing the foam insulation between floor joists in the crawl space the foam board is installed against the crawl space foundation walls. In other words rigid foam can be applied on walls foundations and roofs and works great for both retrofits and new constructions.

There are several ways to install subflooring above the rigid foam. Fill voids around the top of the wall where the foundation meets the floor framing and gaps around wiring. Here s what you need to know. But insulating your floors is a good idea for many reasons including energy efficiency and height adjustments.

You can attach wood sleepers to the floor fill the gaps with rigid foam insulation and then apply your finish flooring. This foam board insulation is the rigid pink or blue panels that can be found at home centers in many different thicknesses. But it is important to know how to install foam board insulation properly. You can use either one or two layers of plywood or osb and the subflooring can either be fastened to the concrete with long tapcon screws or it can simply float above the foam.

Unlike fiberglass rigid foam insulation does not absorb water support mold or allow air to pass through providing that joints between boards are sealed with tape. Rigid foam insulation offers a thermal resistance between r 5 and r 8 roughly twice that offered by traditional batt insulation. Not only does it provide high r values but foam board insulation is also easy to install lightweight and can be used in any room of your home. Or as demonstrated here you can cover the slab with rigid foam insulation add two layers of plywood and then add the finish flooring.

Squirt either caulk or expanding foam insulation in every hole or break in the floor. Eps is used under roofing over foundation walls and beneath siding.