Roof Insulation R Value Chart

R value of various materials.

Roof insulation r value chart.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. For a very good introductory overview article on r value see r values over at the website of. R value is used in the united states.

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. To convert rsi to r value multiply the rsi by 5 67826. Recommended home insulation r values. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

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. R value chart for enerfoil tm rigid foam faced insulation. Thickness inches r value in i p imperial rsi r value in metric 0 5. Conditioned per atsm c1289 test method astm c5181 2.

The percentage increase increase increase original number 100. See the department of energy s doe ranges for recommended levels of insulation below. 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. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1.

The higher the r value the better the thermal performance of the insulation. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value. R3 r18 r21 total roof r value. The table below shows what levels of insulation are cost effective for different climates and.

Rsi r value système international is the metric equivalent. R value is a measure of insulation s ability to resist heat traveling through it. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. Insulation level are specified by r value.

The increase r21 r3 exactly 18 the value by which you are increasing the r value. You should of course see the manufacturer provided technical data sheet for the r value of specific products.