Flat Roof Insulation Board R Value

R value measures how well certain building insulation materials can resist heat.

Flat roof insulation board r value.

The average cost of flat roof insulation is 0 67 per square foot for 1 inch thick polyiso with 6 r value. Conditioned per atsm c1289 test method astm c5181 2. The higher the r value the greater the insulation performance. We recommend having at least 20 r value worth of material for optimal energy efficiency.

To convert rsi to r value multiply the rsi by 5 67826. R value of various materials. When determining how much insulation you need don t guesstimate calculate. 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. Working with home insulation boards insulation panels typically come in 4x8 foot sheets. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Smaller sizes are also available.

High quality rigid foam insulation that is properly installed will greatly improve ventilation eliminate drastic temperature fluctuations inside the home and protect from leaks. They re much lighter and easier to work with than plywood sheets. For a 1 inch board equivalent of 6 r value. You can expect to pay about 55 100 sq ft.

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. 2020 insulation cost estimate foam board insulation prices. 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. Closed cell polyisocyanurate foam technology provides additional insulation value r value of 2 5 with lightweight and low water absorption characteristics.

Here are the best insulation materials along with prices features and r values. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Minimum insulation r value requirements non residential above roof deck. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

This material offers the highest r values about r 6 to 6 5. Thickness inches r value in i p imperial rsi r value in metric 0 5. Products with foil facing help the panels resist moisture vapor. Combining different types of insulation to increase r value.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Know exactly how much you need with our project calculators.