Roof Insulation Dimensions

Insulation tapered polyiso foam roof insulation 3 5 tapered polyiso insulation provides a logical and economical answer for roofs that do not permit adequate positive drainage like low slope roofs.

Roof insulation dimensions.

The higher the r value the better a material performs as a thermal insulator. Board size 4 x 4 1 21 m x 1 21 m. Standard material is johns manville enrgy 3tapered and flat polyisocyanurate roof insulation. Insulation for 2x4 walls most wall assemblies especially those in older homes are built with two by four 2x4 studs.

So you need to know an insulation product s thickness as well as its r value in order to compare it to another product. The same insulation will hold more heat the thicker it is installed. Eight inches of poor quality insulation may have a higher and better r value than one inch of top quality insulation. In most wall applications you will use r 13 or r 15 kraft faced fiberglass insulation rolls for these two by four stud walls.

R value is used as a measurement of the effectiveness of thermal insulating materials. Location of r value on a product data sheet. Since modern two by fours are not 4 inches the true depth of the wall cavity is 3 1 2 inches. R value table for roofing materials and building insulation.

Types of roof insulation.