Comfortech® have worked with Design Navigator to develop an Edge Compression R-Value Calculator. This calculator allows us to extrapolate the product R-value across the last 500mm of the ceiling or roof perimeter, under compression to ensure you will meet the required R3.3 construction R-value under the 5th Edition of H1.
The calculator does this by allowing us to input the roof pitch in degrees, the truss chord depth as 90mm or 140mm, selecting the Pink® Superbatts® product range, and the insulation guard which helps to maintain the ventilation pathway at the perimeter. If the minimum product R-value is not achieved, a raised heel height can be input to reduce the edge compression, allowing you to meet the product and construction R-value requirements. This information can then be included with your H1 calculation to demonstrate compliance with H1.