R Value For Flat Roof Insulation

For a very good introductory overview article on r value see r values over at the website of.

R value for flat roof insulation.

Minimum insulation r value requirements non residential above roof deck. It is top quality and the most cost effective product for your flat roof. R value of various materials. Recommended insulation levels for retrofitting existing wood framed buildings.

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. 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. Flat expanded polystryene eps roof insulation provides high long term r value of eps and labor saving face laminates.

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. You should of course see the manufacturer provided technical data sheet for the r value of specific products. While expensive the best insulation is polyiso rigid foam. The average r value for some common roof materials include.

To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. Add insulation to attic. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. R value measures how well certain building insulation materials can resist heat.

Know exactly how much you need with our project calculators. Rsi r value système international is the metric equivalent. State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010 2 r 20 3 r 20 state local mo missouri 2012 iecc 4 r 25 5 r 25 state only mt montana 2012 iecc 6 r 30. We recommend having at least 20 r value worth of material for optimal energy efficiency.

When determining how much insulation you need don t guesstimate calculate. R value is calculated by more than just the insulation. 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.

Existing 3 4 inches of insulation. For a 1 inch board equivalent of 6 r value. You can expect to pay about 55 100 sq ft. 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.

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