Roof Insulation R Value Chart

You should of course see the manufacturer provided technical data sheet for the r value of specific products.

Roof insulation r value chart.

Conditioned per atsm c1289 test method astm c5181 2. For a very good introductory overview article on r value see r values over at the website of. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. To convert rsi to r value multiply the rsi by 5 67826.

The percentage increase increase increase original number 100. The table below shows what levels of insulation are cost effective for different climates and. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. R value is used in the united states.

For example a wall with 3 fiberglass batting r value of 10 8 11 9 may have an overall r value of nearly 14 because of siding sheathing and drywall. As a benchmark one inch of solid wood has an r value of 1. R3 r18 r21 total roof r value. See the department of energy s doe ranges for recommended levels of insulation below.

Thickness inches r value in i p imperial rsi r value in metric 0 5. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. 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. R value insulation chart 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.

Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. Rsi r value système international is the metric equivalent. The higher the r value the better the thermal performance of the insulation. Insulation level are specified by r value.

R value is a measure of insulation s ability to resist heat traveling through it. The increase r21 r3 exactly 18 the value by which you are increasing the r value. Recommended home insulation r values. In comparison an inch of blown fiberglass insulation has an r value of 3 1 3 4 and an inch of blown cellulose in an attic has an r value of 3 2 3 7.

R value chart for enerfoil tm rigid foam faced insulation. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1.