Roof Insulation R Value Canada

I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number.

Roof insulation r value canada.

R values of common types of insulation. The higher the r value the greater the insulation performance. The increase r21 r3 exactly 18 the value by which you are increasing the r value. R3 r18 r21 total roof r value.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. R value measures how well certain building insulation materials can resist heat. The higher rsi value of rigid insulation means a smaller increase in the roof thickness although several layers of insulation may be needed to meet the desired rsi level. If installed uncompressed in a 152 mm cavity e g some manufactured framing products it will retain its full thermal resistance value of 3 52 m2 k w.

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. 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. Thickness inches r value in i p imperial rsi r value in metric 0 5. Know exactly how much you need with our project calculators.

See the department of energy s doe ranges for recommended levels of insulation below. For a very good introductory overview article on r value see r values over at the website of. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. The recommended r value for attic insulation in ontario is between r 50 and r 60.

R value of various materials. The percentage increase increase increase original number 100. Conditioned per atsm c1289 test method astm c5181 2. The r value of the insulation for every inch of thickness depends on the type of insulation.

An rsi 3 52 r20 per 152 mm batt compressed into a 140 mm cavity has a thermal resistance value of 3 34 r19. In such cases where r value is assigned this may decrease the r value requirement for batt insulation. One method involves installing rigid board insulation on top of the existing roof see figure 5 25. When determining how much insulation you need don t guesstimate calculate.