Compressing Insulation In Attic

Compressing a thicker fiberglass batt into a standard stud space reduces the insulation s r value.

Compressing insulation in attic.

Compressing r 19 insulation typically 6 thick into a 2x4 stud cavity that is 3 deep. Open insulation packages carefully and only as you need them. We used batt insulation for our project. To help prevent frozen pipes insulate only on the cold side.

Compressing the material changes the r value. Insulation expands once unpackaged so leave it wrapped until you are ready to use it. Also bear in mind that if you compress insulation in order to make it fit the product loses much of its r. 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.

Determine the type of insulation needed for your 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. So it s time to pay close attention to what s happening up there. The north american insulation manufacturers association naima has a little two page document about compressing fiberglass insulation pdf.

Batt and roll insulation also called blanket insulation are designed to fit between joists and wall stud cavities. 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. Here s what they say. Insulation expands quickly once you open the packaging.

Compressing insulation reduces its r value. In most communities local lumberyards stock fiberglass insulation that meets local building codes. Commonly used for diy projects they work well in open spaces like attic floors.