R Value For Flat Roof Insulation

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

R value for flat roof insulation.

While expensive the best insulation is polyiso rigid foam. R value is calculated by more than just the insulation. Know exactly how much you need with our project calculators. Recommended insulation levels for retrofitting existing wood framed buildings.

See the department of energy s doe ranges for recommended levels of insulation below. You can expect to pay about 55 100 sq ft. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1. Existing 3 4 inches of 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. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. Minimum insulation r value requirements non residential above roof deck. Add insulation to attic.

It is top quality and the most cost effective product for your flat roof. For a very good introductory overview article on r value see r values over at the website of. We recommend having at least 20 r value worth of material for optimal energy efficiency. Flat expanded polystryene eps roof insulation is suitable for use with all roofing membrane materials flat eps roof insulation is compatible with loose laid and attached single ply membranes conventional built up roofing or modified bitumen systems.

To convert rsi to r value multiply the rsi by 5 67826. Fm approved subject to the conditions of approval as a roof insulation when installed as shown in the current edition of the factory mutual research approvals guide. The higher the r value the greater the insulation performance. 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 calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. R value of various materials. The average r value for some common roof materials include. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

Flat expanded polystryene eps roof insulation provides high long term r value of eps and labor saving face laminates. For a 1 inch board equivalent of 6 r value. R value is used in the united states. Rsi r value système international is the metric equivalent.

Excellent lttr value compared to any other fm class 1 rated products of equivalent thickness.