b'PMRAtheseaddedlayerswereintendedto enhance drainage and prevent clogging, they also promoted more uniform water The study suggests that placing drainage layersdistributionacrosstheroofsurface. This inadvertently increased the area of beneath channelled boards may be counterproductive,membrane contact with water, thereby enhancingheattransferandreducing thermal resistance.as it alters water flow patterns at the membrane,InSource2,PMRA-8(channeled insulation)lost58-72percentofits increasing water contact and heat transfer. R-valueunderrain,whilePMRA-9, with added Fabrene filter fabric, showed slightlyhigherlosses(65-71percent) duetoincreasedwaterspreadatthe membrane level.In Source 3, PMRA-14 and PMRA-12 (flatinsulation,withandwithouta TAILORED SOLUTIONSdrainage layer) had similar performance, TO FIT YOURlosing 60-80 per cent of its R-value, indi-cating minimal impact from the drainage TAPEREDlayer. However, PMRA-18, with a Tyvek INSULATION NEEDS water flow restricting layer, significantly reduced R-value loss to 27-32 per cent, showingthatblockingwaterfrom reaching the membrane greatly improves We design the most efficient and optimal layouts to ensure thermal performance.proper water drainage.Overall, the study reveals that rain-E-designEstimationSite InspectionLabor Saving Designs watercoolingsignificantlylowersthe Proudly serving roofing contractors coast to coast acrossthermalperformanceofPMRAs, Canada for over 40 years. even at low rainfall rates. The effective R-valuedecreasesfollowingaloga-rithmic pattern, with an average loss of Contact us for your next project posislope.com 59.0 per cent4.2 per cent at 0.25 mm/hr and 74.6 per cent5.3 per cent at 2.00 mm/hr. After simulated rain events, PMRAs retained considerable moisture, further reducing their thermal efficiency. NON-PENETRATINGComponentslikechanneledinsula-tion,filterfabrics(suchasFabrene) SAFETY RAILING andwaterflowrestrictinglayersinflu-enced thermal behaviour. The addition of Fabrene caused a relative decline in EXPECTperformance that worsened with heavier OUTSTANDINGrainfall, whereas Tyvek helped mitigate SERVICE FROMheat loss by preventing water from pene-DESIGN TO ROOFTOP VSS COMPACT SYSTEM - MICA CREEK, BC trating interior layers. Installing drainage layers like DB-9000 and Hydrodrain-300 generallydecreasedthermalperfor- 50 lb recycled rubber bases mance compared to PMRA-2 with chan- Anodized aluminum railing nelled boards. The study suggests thatComplies with NBC, BC OHS & CSA placingdrainagelayersbeneathchan- 10 year warranty VSS CLASSIC SYSTEM - KELOWNA, BC nelledboardsmaybecounterproduc-tive, as it alters water flow patterns at the 1-844-855-4273 membrane, increasing water contact and info@deltaprevention.com heat transfer. Furthermore, the tightness and fit of insulation joints play a crucial 26 lROOFINGBClFALL 2025'