R Value For Flat Roof Insulation

It is top quality and the most cost effective product for your flat roof.

R value for flat roof insulation.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. 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. Add insulation to attic. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

Recommended insulation levels for retrofitting existing wood framed buildings. R value is used in the united states. You should of course see the manufacturer provided technical data sheet for the r value of specific products. See the department of energy s doe ranges for recommended levels of insulation below.

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

Existing 3 4 inches of insulation. Minimum insulation r value requirements non residential above roof deck. R value of various materials. R value measures how well certain building insulation materials can resist heat.

To convert rsi to r value multiply the rsi by 5 67826. 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. While expensive the best insulation is polyiso rigid foam. 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. Rsi r value système international is the metric equivalent. Know exactly how much you need with our project calculators. You can expect to pay about 55 100 sq ft.

For a 1 inch board equivalent of 6 r value. The higher the r value the greater the insulation performance. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. Flat expanded polystryene eps roof insulation provides high long term r value of eps and labor saving face laminates.

For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1.