R30 Roof Insulation Thickness

Drill holes in the sheathing and blow insulation into the empty wall.

R30 roof insulation thickness.

As a foil faced polyisocyanurate foam insulation enerfoil tm s r value actually more than doubles. Rigid foam insulation provides the same r factor with approximately one half the thickness. 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. 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.

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. 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. This is a significant difference and thus why r 49 batt insulation is used typically in colder climates. See the department of energy s doe ranges for recommended levels of insulation below.

Fiberglass panels and rolls with an r 30 insulation value have a typical thickness of eight to nine and a half inches. Wall insulation whenever exterior siding is removed on an. 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. 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.

Professional should specify insulation thickness based r value on the 6 0 r inch design guideline associated with the old lttr test method. The thickness of r 30 insulation varies depending on the type of insulation used. So you need to know an insulation product s thickness as well as its r value in order to compare it to another product. Note that r30 batt insulation thickness is just 9 1 2 inches thick where as r 49 batt insulation thickness is 15 1 2 inches.