The Owens Corning effective thermal resistance calculator uses the calculation methodology, material values and framing factors listed in appendix A-18.104.22.168.1 of the National Building Code of Canada. Wood structural members are of the spruce-pine-fir type with a thermal resistance of RSI 0.0085/mm of thickness. Steel stud members are available as an option for walls above grade assemblies only with a thermal resistance of RSI 0.0000161/mm.
The user can view the individual material thermal resistance values used in the calculation for the design assembly chosen by clicking on the “Download Results” icon. Assembly details are grouped by Continuous and Non-Continuous layers.
Owens Corning has been conservative in our approach when it comes to the thermal resistance values for vented air spaces created by vertical strapping on exterior wall assemblies. The calculator does not attribute a thermal resistance value for the air gap created by the wood strapping or one for any material outboard of such a VENTED space. The user can simply add the values for those layers to the result generated by the calculator if the Province or Authority having jurisdiction recognizes and allows a thermal resistance contribution for those layers.
Please contact your local Owens Corning Technical Services Engineer if you require any assistance or additional information.
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