Rigid Insulation R Values Roof

The thicker the foam core the slower the diffusion and thermal aging which is why the r inch increases with thicker board.

Rigid insulation r values roof.

The r value for foamular xps insulation is provided from testing at two mean temperatures 40ºf and 75ºf and from two aging conditioning techniques 180 day real time aged as mandated by astm c578 and a method of accelerated aging sometimes called long term thermal resistance lttr per can ulc s770 03. R value measures how well certain building insulation materials can resist heat. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Foamular xps roof insulation for commercial buildings page 5 foamular xps roof insulation for commercial buildings foamular xps insulation is a rigid foam insulation which meets the needs of today s design professionals for a truly sustainable insulation product.

I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. Resources johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. Choose rigid insulation wisely and consider the effect its characteristics will have on the performance of the your project overall product cost and the best way to get the bang for your buck. Rigid foam insulation packs a lot of r value into a thin package but not all rigid foam performs the same.

The higher the r value the greater the insulation performance. Calculate percent improvement in r value. The higher the r value the better a material performs as a thermal insulator. Let s use the r value of iko s polyiso insulation enerfoil tm as an example.

R3 r18 r21 total roof r value. Owens corning insulation products help improve thermal performance and control moisture in commercial institutional and. R panel is manufactured with a closed cell polyisocyanurate foam core bonded to fiberglass reinforced facers and designed for use over metal nailable and non nailable roof decks with a variety of membrane systems. To convert rsi to r value multiply the rsi by 5 67826.

R value is used as a measurement of the effectiveness of thermal insulating materials. The increase r21 r3 exactly 18 the value by which you are increasing the r value. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. Most insulation manufacturers will first list their insulation s r value for a one inch sample then they ll give you a chart demonstrating the other r values you can achieve if you install a thicker version of their product.

The lttr a 15 year time weighted average r value is largely affected by thermal aging where air diffuses in and blowing agent diffuses out of the foam.