b'Staggered Insulation LayersImprove Commercial Roof Performance with Staggered Insulation Layers By Marcin Pazera, PhDS electingtherightcomponentsforaprojectcandramaticallyMembrane billows with wind speed, bringingBasic System:improvetheperformanceandlongevityoftheoverallbuild-ing. In a commercial roofing project, the chosen insulation andhumid interior air up to the membranethe installation technique are critical to a buildings resilience andOutside Conditioned air thermal efficiency. Membrane readily reaches From a physics standpoint, energy flows from a region of high toInsulation membranelow potential (from warm to cold). Therefore, a significant amount of heat can leave a building through an inadequately insulated roof as- Porous Decksembly during heating season (winter) and enter a building through an inadequately insulated roof assembly during cooling season (summer).Moist Air Building InteriorA building with an under-insulated roof assembly may require more energy to compensate for these heat gains and losses. Reduced membrane billowing, Good:The benefits of installing multiple, staggered layers of rigid boarddue to double layered insulation Outside Use two layers insulation have been well known for years. Industry authorities, in- Membrane of polyiso with cludingNationalRoofingContractorsAssociation(NRCA),OakInsulation, Ridge National Laboratory (ORNL), Canadian Roofing Contractorsdoublestaggered jointslayers, Association (CRCA) and International Institute of Building Enclo- staggeredsure Consultants (IIBEC), formerly RCI, Inc., have recognized thesePorous Deckbenefits; and contractors, designers and specifiers have followed theMoist Air Building Interior 1roofing industrys longstanding recommendation for the installation of staggered insulation layers. Figure 1: Multiple, staggered layers of insulation can minimize air infiltration and reduce or prevent condensation in the roof system. Credit: GAFUsing the optimal roof insulation product also will impact perfor-mance. Polyiso insulation offers key advantages in meeting stricter NOW building standards and improving energy efficiency. Polyiso has a high A NEW ROOFING design R-value compared to XPS, EPS and mineral wool board. Light-AVAILABLEIN BULK FROMASPHALT WITH Aweight and easy to trim, polyiso can be layered to reach the desired LOWER EVT WHICH REDUCES FUMES R-values without being cumbersome to install.By BITUMAR AND ODOUR.Why Are Multiple, Staggered Layers of Insulation Important?11155 St-Catherine Street EastMontreal-East, QCH1B 0A4 In 2015, the International Energy Conservation Code (IECC) in-Tel. : 514 645-4561 creased the R-value requirements for the opaque thermal envelope in bitumar.com many climate zones across the United States. As a practical matter, ZEROODOUR 40 % most roofs will require two or more layers of insulation to meet the 35 % local energy code requirements. In the 2018 version, the IECC wasWhen cold 30 %updated with specific installation requirements for continuous roof % of fumes in the air 75 % Reduction Up to 177C 25 %insulation. The 2018 IECC explicitly calls for continuous insulation75 % less fumes than 20 % regular roofing asphalt 15 % board to be installed in not less than two layers and the edge jointsBURPAK ZERO contains an10 % between each layer of insulation shall be staggered (Section C402.2.1 odour suppressant which 5 % ZERO Regular BUR Roof assembly). combined with a lower0 %temperature of installation,93 121 149 176 204 232* 260 288** 316C Staggering the joints of continuous insulation layers offer a number minimizes asphalt odour Temperature of benefits: Zero complaint on odour * Theidealviscositytemperatureistypicallylowerby23Cfor BURPAKZEROwhencomparedwithregularroofingasphalt. Increased thermal performance/reduced thermal loss: The stag-Complaints are timeTherefore,thereisnoneedforthekettletemperaturegered joints on multiple layers of insulation offset gaps where heat consuming and reducetoexceed232CwhenusingBURPAKZERO.productivity on job sites **MaximumtemperatureofakettleasperASTMD312. could flow between adjacent boards. The staggered approach to in-stalling insulation reduces thermal bridging in the roof assembly. 12ONTARIO ROOFING NEWSISSUE 2 2019 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'