Foam Insulation Board Over Windows

Even with all the joints sealed it is still not recommended to have a vertical joint in the sheathing occur over a window head.

Foam insulation board over windows.

It provides an r value of 6 per inch of thickness and often comes foil faced to help reflect radiant heat. There are basically two types of reflective insulation that can be used by homeowners today. This is an even more dense and more expensive foam board insulation. Consider using spray foam insulation as well to seal smaller cracks and gaps.

The first is a foam backed foil that is much like the blue foam insulation used on a home s outer shell. Insulating boards are just one of the many types of foam insulation. When to use foam board insulation. Typically sold as sheet insulation in a standard size of 4 x 8 foam insulation panels can help reduce energy costs get a handle on moisture control and more.

For the foam sheathing to be an effective air barrier and provide the drainage plane the joints between the boards must be sealed. It comes in sheets the same size as plywood and is easy to work with. Flash the sheathing around the buck to the window opening with tape or liquid flashing before installing the exterior foam insulation. Shop at lowe s to find the foam sheeting you need for your next insulation project.

Polyisocyanurate is another option coming in as the densest and more expensive option for foam board. If your building has outie windows you should use the rigid foam or housewrap installed on the exterior side of the rigid foam as your wrb. Prepare a rough opening for a nail fin window over exterior rigid foam insulation. Polyiso comes in several thicknesses and is used over house sheathing underneath siding or in attic spaces where its reflective properties are very effective.

Instead you should use zip sheathing asphalt felt or housewrap as your wrb.