R30 Roof Insulation Thickness

Rated r value and thickness of insulation r value r6 r11.

R30 roof insulation thickness.

Rigid foam insulation provides the same r factor with approximately one half the thickness. The thickness of r 30 insulation varies depending on the type of insulation used. Wall insulation whenever exterior siding is removed on an. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.

Professional should specify insulation thickness based r value on the 6 0 r inch design guideline associated with the old lttr test method. Eight inches of poor quality insulation may have a higher and better r value than one inch of top quality insulation. Drill holes in the sheathing and blow insulation into the empty wall. R 30 insulation thickness or even r 19 thickness is often used in warmer climates.

Insulation thickness to reach the r 30 value depends on the insulation material but fiberglass batts of r 30 insulation are 9 1 2 inches thick. Likewise for jobs that will be permitted in 2014 the design professional should specify insulation thickness based on the 5 7 r inch design guideline associated with the new lttr test method. As a foil faced polyisocyanurate foam insulation enerfoil tm s r value actually more than doubles. Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces.

So you need to know an insulation product s thickness as well as its r value in order to compare it to another product. R30 c r30 r38 c r38 insulation thickness 1 75 2 5 3 5 3 5 3 5 6 25 5 5 6 5 8 8 5 10 10 12 all listed thicknesses are approximate and may vary by 0 5 inches. Fiberglass panels and rolls with an r 30 insulation value have a typical thickness of eight to nine and a half inches. See the department of energy s doe ranges for recommended levels of insulation below.