Compressing Insulation In Attic

When you compress fiber glass batt insulation the r value per inch goes up but the overall r value goes down because you have less inches or thickness of insulation.

Compressing insulation in attic.

Around electrical boxes notch rather than compress the batt then tuck the cutout behind the box. When you compress fiber glass batt insulation the r value per inch goes up but the overall r value goes down because you have less inches or thickness of insulation. The north american insulation manufacturers association naima has a little two page document about compressing fiberglass insulation pdf. Proper attic insulation is the best way to prevent heat loss in the winter and retain cool air in the summer.

If you live in an area where frozen pipes are a concern make sure the insulation protects the pipes from cold air. Batt and roll insulation also called blanket insulation are designed to fit between joists and wall stud cavities. Compressing insulation reduces its r value. Commonly used for diy projects they work well in open spaces like attic floors.

We used batt insulation for our project. Compressing the material changes the r value. Here s what they say. Compressing a thicker fiberglass batt into a standard stud space reduces the insulation s r value.

Determine the type of insulation needed for your attic. If you know you aren t going to convert the attic in the future that leads you one direction compressing the insulation is fine maybe you don t care so much about head height and can add some more thickness to improve the insulation etc and if you know that an attic conversion is viable and that you are likely to want to pursue that in. Insulation expands quickly once you open the packaging. Insulation expands once unpackaged so leave it wrapped until you are ready to use it.

In most communities local lumberyards stock fiberglass insulation that meets local building codes. Compressing r 19 insulation typically 6 thick into a 2x4 stud cavity that is 3 deep. To help prevent frozen pipes insulate only on the cold side.