For a 1 inch board equivalent of 6 r value.
Flat roof insulation board r value.
High quality rigid foam insulation that is properly installed will greatly improve ventilation eliminate drastic temperature fluctuations inside the home and protect from leaks.
We recommend having at least 20 r value worth of material for optimal energy efficiency.
Closed cell polyisocyanurate foam technology provides additional insulation value r value of 2 5 with lightweight and low water absorption characteristics.
This material offers the highest r values about r 6 to 6 5.
When determining how much insulation you need don t guesstimate calculate.
They re much lighter and easier to work with than plywood sheets.
Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.
2020 insulation cost estimate foam board insulation prices.
R value of various materials.
High density polyisocyanurate foam core.
To convert rsi to r value multiply the rsi by 5 67826.
R value measures how well certain building insulation materials can resist heat.
Working with home insulation boards insulation panels typically come in 4x8 foot sheets.
Combining different types of insulation to increase r value.
You can expect to pay about 55 100 sq ft.
Conditioned per atsm c1289 test method astm c5181 2.
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.
Products with foil facing help the panels resist moisture vapor.
For a very good introductory overview article on r value see r values over at the website of.
You should of course see the manufacturer provided technical data sheet for the r value of specific products.
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.
Smaller sizes are also available.
Minimum insulation r value requirements non residential above roof deck.
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.
For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721.
Here are the best insulation materials along with prices features and r values.
It is top quality and the most cost effective product for your flat roof.
The higher the r value the greater the insulation performance.
Know exactly how much you need with our project calculators.
The average cost of flat roof insulation is 0 67 per square foot for 1 inch thick polyiso with 6 r value.