Flat Roof Insulation Board R Value

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

Flat roof insulation board r value.

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. R value chart for enerfoil tm rigid foam faced insulation. Know exactly how much you need with our project calculators. High quality rigid foam insulation that is properly installed will greatly improve ventilation eliminate drastic temperature fluctuations inside the home and protect from leaks.

To convert rsi to r value multiply the rsi by 5 67826. For a very good introductory overview article on r value see r values over at the website of. R value of various materials. They re much lighter and easier to work with than plywood sheets.

For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Conditioned per atsm c1289 test method astm c5181 2. Minimum insulation r value requirements non residential above roof deck. The higher the r value the greater the insulation performance.

When determining how much insulation you need don t guesstimate calculate. Products with foil facing help the panels resist moisture vapor. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. 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.

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. The average cost of flat roof insulation is 0 67 per square foot for 1 inch thick polyiso with 6 r value. It is top quality and the most cost effective product for your flat roof. Here are the best insulation materials along with prices features and r values.

For a 1 inch board equivalent of 6 r value. Smaller sizes are also available. Thickness inches r value in i p imperial rsi r value in metric 0 5. 2020 insulation cost estimate foam board insulation prices.

High density polyisocyanurate foam core. Combining different types of insulation to increase r value. This material offers the highest r values about r 6 to 6 5. We recommend having at least 20 r value worth of material for optimal energy efficiency.

Working with home insulation boards insulation panels typically come in 4x8 foot sheets. You can expect to pay about 55 100 sq ft.