R Value For Flat Roof Insulation

You can expect to pay about 55 100 sq ft.

R value for flat roof insulation.

Know exactly how much you need with our project calculators. Add insulation to attic. While expensive the best insulation is polyiso rigid foam. Minimum insulation r value requirements non residential above roof deck.

For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1. For a 1 inch board equivalent of 6 r value. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. 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. See the department of energy s doe ranges for recommended levels of insulation below. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

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 average r value for some common roof materials include. When determining how much insulation you need don t guesstimate calculate. The higher the r value the greater the insulation performance.

Existing 3 4 inches of insulation. R value is calculated by more than just the insulation. R value is used in the united states. 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.

Flat expanded polystryene eps roof insulation provides high long term r value of eps and labor saving face laminates. To convert rsi to r value multiply the rsi by 5 67826. R value measures how well certain building insulation materials can resist heat. For a very good introductory overview article on r value see r values over at the website of.

R value of various materials. It is top quality and the most cost effective product for your flat roof. We recommend having at least 20 r value worth of material for optimal energy efficiency. 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.