b'respective deck engagement. Fig. 18 shows three dif ferent fastener sizes along with the respective deck engagement. Fig. 18 shows physical characteristics of the head, tip, and three dif ferent fastener sizes along with the thread. Fig.19 shows plotted FPR data for physical characteristics of the head, tip, and five fasteners with four different types of thread. Fig.19 shows plotted FPR data for decks. The data shows that the FPR is higher five fasteners with four different types of with a greater shank diameter, irrespec tive of decks. The data shows that the FPR is higher the deck types. The data also shows that the with a greater shank diameter, irrespec tive of FPR for two differ ent sources with the same the deck types. The data also shows that the fastener type (#15 or #21) measured different FPR for two differ ent sources with the same values, respectively.fastener type (#15 or #21) measured different Fastener Plate/Membrane Engagement values, respectively.in a MARS: This engagement keeps the Fastener Plate/Membrane Engagement membrane in place. The barbed plates provide in a MARS: This engagement keeps the a better clamping force compared to smooth membrane in place. The barbed plates provide ones. The flat, smooth plate allows membrane a better clamping force compared to smooth slippage and tearing along the fastener shank, Figure 14.Membrane fastener rows are perpendicular to the deck flanges. ones. The flat, smooth plate allows membrane as shown in Fig. 20 (left), even at low wind slippage and tearing along the fastener shank, Figure 14.Membrane fastener rows are perpendicular to the deck flanges. uplift pressures. At high wind uplift pressures, as shown in Fig. 20 (left), even at low wind the barbed plate bends due to the membrane Technical Article respective deck engagement. Fig. 18 showsuplift pressures. At high wind uplift pressures, three dif ferent fastener sizes along with thebil lowing and loses its clamping force; the physical characteristics of the head, tip, andthe barbed plate bends due to the membrane Thermosetmembraneseamshavethread. Fig.19 shows plotted FPR data formembrane is stretched along the deformed plate tapeand/oradhesive.MBmem- five fasteners with four different types ofbill owing and loses its clamping force; the decks. The data shows that the FPR is higherportion, which results in the membrane being brane seams are heat air welded. Thewith a greater shank diameter, irrespect ive ofmembrane is stretched along the deformed plate SIGDERS research showed that us- the deck types. The data also shows that thetorn as shown in Fig. 20 (right). If the membrane ing improper speed and temperatureFPR for two differ ent sources with the sameportion, which results in the membrane being for hot/heat air welding results in afastener type (#15 or #21) measured differenttensile strength was lower than the wind uplift very weak seam, as shown in Fig. 12.values, respectively. torn as shown in Fig. 20 (right). If the membrane Fastener Plate/Membrane Engagementload, the membrane would stretch and tear Manufacturershaveinventednewin a MARS: This engagement keeps thetensile strength was lower than the wind uplift seam application technologies suchmembrane in place. The barbed plates providearound the fastener plates.asself-adheredseamsortorch-freea better clamping force compared to smoothload, the membrane would stretch and tear Figure 15.Substrate pullout from the fastener and plate for a partially attached (hybrid) seamsinrecentyears,withclaimsones. The flat, smooth plate allows membraneFastener Plate/Membrane Engagement Figure 14. Membrane fastener rows are perpendicular to the deck flanges. slippage and tearing along the fastener shank,around the fastener plates.that the new seam application tech- membrane roofing system. own in Fig. 20 (left), even at low windin a PARS: The membrane is adhered to the Figure 15. Substrate pullout from the fastener and plate for a partially attached (hybrid) membrane roofing system.nologiesarebetterthanthetradi- Figure 15.Substrate pullout from the fastener and plate for a partially attached (hybrid) as shuplift pressures. At high wind uplift pressures,Fastener Plate/Membrane Engagement tional methods. Further research isthe barbed plate bends due to the membranetop surface of the insulation. The insulation is neededtoinvestigatetheweldingmembrane roofing system. in a PARS: The membrane is adhered to the bil lowing and loses its clamping force; the window(temperatureandspeed),membrane is stretched along the deformed platesecured to the deck with fasteners and plates. portion, which results in the membrane beingtop surface of the insulation. The insulation is theinfluenceofambienttempera- torn as shown in Fig. 20 (right). If the membraneBased on SIGDERS research, systems with ture to self-adhered seams and torch- tensile strength was lower than the wind upliftsecured to the deck with fasteners and plates. free seams on wind uplift resistance. load, the membrane would stretch and tearsmooth-surface insu lation plates increased the Figure 15. Substrate pullout from the fastener and plate for a partially attached (hybrid)around the fastener plates. Based on SIGDERS research, systems with ticFor the MARS with thermoplas- Fastener Plate/Membrane Engagementwind uplift resist ance by 50% more than systems membrane roofing system. in a PARS: The membrane is adhered to thesmooth-surface insul ation plates increased the membrane, there are two seaming techniques,one-sideweld(OSW)top surface of the insulation. The insulation iswith textured insulation plates. Fig. 21 illustrates anddouble-sideweld(DSW),assecured to the deck with fasteners and plates.wind uplift resis tance by 50% more than systems showninFig.13.TheSIGDERSBased on SIGDERS research, systems withthe failure modes for different insulation plate research showed the roofing systemsmooth-surface insul ation plates increased thewith textured insulation plates. Fig. 21 illustrates withDSWperformedbetterthanwind uplift resist ance by 50% more than systemsconfigurations. Textured hexago nal plates offer with textured insulation plates. Fig. 21 illustratesthe failure modes for different insulation plate OSW.TheDSWsystemsustainedthe failure modes for different insulation platethe required contact area with the membrane aminimumof15-per-centhigherconfigurations. Textured hexagonal plates offerconfigurations. Textured hexago nal plates offer wind uplift resistance than the OSWthe required contact area with the membraneonly through the outer and middle rims of the system. The OSW system developsonly through the outer and middle rims of thethe required contact area with the membrane Figure 16.Facer delaminationooth circu res for an adhesive applied membrane roofing system. plates. Smooth circular metal and plastic plates Figure 16. Facer delamination failures for an adhesive applied membrane roofing system.Figure 16. Facer delamination failures for an adhesive applied membrane roofing system. plates. Sm failu lar metal and plastic plates have a larger contact surface area to increase theonly through the outer and middle rims of the bonding strength with the membrane. have a larger contact surface area to increase the Figure 16.Facer delamination failures for an adhesive applied membrane roofing system. plates. Smooth circular metal and plastic plates an asymmetrical force by pulling thesufficient compressive strength andfor example, will stand up to the rig-Q11: WHAT IS THE ROLE OFpull-throughstrength.Aweakerors of the site activity better. bonding strength with the membrane.bottommembrane.Thefastenerspull-throughstrengthcancauseahave a larger contact surface area to increase the ADHESIVE, ADHESIVE AMOUNT, areexperiencingasingle-direction AND CURING TIME?wind load, which will y factorthe fas- cone cut on the substrate board, asQ10: What Is the Role ofbonding strength with the membrane.Adhesive curing time is the kerockto deter-mine the adhesive bond strength. The highershown in Fig. 15. In the AARS andFasteners and Plates? Q11: WHAT IS THE ROLE OF teners sideways and cause fatigue de-the adhesive bond strength, the better the formation at the steel deck/fastenerPARS, the membrane is adhered to wind uplift resistance. For a scenario testedthe top surface of the insulation/cov- Accessories,fastenersandplatesADHESIVE, ADHESIVE AMOUNT, engagementlocations.Thisfatigue by SIGDERS, a system failed below 2.87 kPaer board. The interface peel strengthare used to secure either the mem- Q11: WHAT IS THE ROLE OF ultimatelyresultsinthefastenerbrane or insulation or both to theAND CURING TIME?(60psf) with 14 days of curing time. The system pulloutfromthesteeldeck.Thebetweenthemembraneandthestructural deck. ADHESIVE, ADHESIVE AMOUNT, had a wind uplift resistance of 3.59 kPa (75 psf) with 21 days of curing time and a wind upliftsubstrate should be able to resist theFastener/DeckEngagement:Adhesive curing time is the key factor to deter-DSWsystemdevelopssymmetrical resistance of 4.31 kPa (90 psf) with 28 days ofshear forces created from the windThe fastener tip and thread designAND CURING TIME?forcesalongthehorizontaldirec- uplift force to avoid the types of fail- mine the adhesive bond strength. The higher curing time. The failure modes for 14, 21, and tion; this minimizes the rocking ac- ures shown in Fig. 16. will determine the fastener pulloutAdhesive curing time is the key factor to deter-28days are adhesive failure between the cap and Figure 17.Wind uplif ft resist ancewith differenttype of vapour barriers. tion onfastener. widthrangesresistance(FPR)withrespectivethe adhesive bond strength, the better the base sheet interface, a cohesive failure between Figure 17. Wind upli t resist ancewith differenttype of vapor barriers. the cap and base sheet interface, and the VBdeckengagement.Fig.18showsmine the adhesive bond strength. The higher Themembrane January 2025from 1.83 m to 3.66 m (6 ft. to 12Q9: What Is the Role of athreedifferentfastenersizesalongwind uplift resistance. For a scenario tested Based on SIGDERSs research, ASTM D7586,15 Vapour Barrier (VB)? withthephysicalcharacteristicsthe adhesive bond strength, the better the IIBEC Interfaceft.).Thespacingbetweentwofas- by SIGDERS, a system failed below 2.87 kPa Standard Test Method for Quantification of Air teners on the seam is called fastenerA VB offers a certain resistanceof the head, tip and thread. Fig. 19wind uplift resistance. For a scenario tested Intrusion in Low-Sloped Mechanically Attached spacing,andas developed in 2011. Ato airflow in addition to its primaryshows plotted FPR data for five fas- (60psf) with 14 days of curing time. The system Roof Assemblies, w spacingbetween the series of tests were carried out by the SIGDERSfunctionoflimitingvapourdiffu- tenerswithfourdifferenttypesofby SIGDERS, a system failed below 2.87 kPa two rows of fasteners on the seam is consortium to quantify air intrusion rate for asion into the roofing system from in- decks. The data shows that the FPRhad a wind uplift resistance of 3.59 kPa (75 psf) called fastener row spacing. The rec-MARS. The result showed the system with a VBdoors. Based on SIGDERS research,is higher with a greater shank diam- (60psf) with 14 days of curing time. The system ommended practice is to orient thewith 21 days of curing time and a wind uplift decreased the air intrusion volume by 50% to fastenerrowsperpendiculartothesystemswindupliftresistancein- eter, irrespective of the deck types.had a wind uplift resistance of 3.59 kPa (75 psf) 80% depending on the bubble pressure (the pressure on the top of the insulation/covercreased by 25 per cent to 50 per centThe data also shows that the FPR forresistance of 4.31 kPa (90 psf) with 28 days of steel deck flange, as shown in Fig. 14.board), membrane deflection, and volumefor systems with a VB than the sys- two different sources with the samewith 21 days of curing time and a wind uplift change, as shown in Fig. 24. tems without a VB, as shown in Fig.fastener type (#15 or #21) measuredcuring time. The failure modes for 14, 21, and Q8: What Is the Role of Q13: WHAT ARE THEresistance of 4.31 kPa (90 psf) with 28 days of Insulation/Cover Board? 17. The wind uplift resistance wasdifferent values, respectively. 28days are adhesive failure between the cap and Figure 18. Physical characteristics of the fasteners. ATTRI BUTES OF A VEGETATEDvaried depending on the air perme- Fastener Plate/Membrane En- curing time. The failure modes for 14, 21, and Inadditiontothedeckand Figure 18. Physical characteristics of the fasteners. ROOF ASSEMBLY (VRA)? impor- ability of the VB and type of roofinggagement in a MARS: This engage- base sheet interface, a cohesive failure between membrane, insulation is also atedsystem. Also, in the field, poly andment keeps the membrane in place.28days are adhesive failure between the cap and In a VRA, a roofing system and a vegetFigure 17.Wind uplift res system are assembled together, as shown in e of vapor barriers. The barbed plates provide a betterthe cap and base sheet interface, and the VB tantsubstrate/roofingcomponent Proudly serving roongistance with different typcontractors coast to coast acrossFig. 25. A roofing assembly consists of a deck andkraft paper are more delicate mate- base sheet interface, a cohesive failure between inaroofingsystem.Theprimary roofing or waterproofing membrane. It includes Canada for over 40 years.function of insulation is to act as arials that may not stand up to footclamping force compared to smooth Figure 17.components such as vapor barriers or retarders,traffic, materials being dragged overones. The flat, smooth plate allowsthe cap and base sheet interface, and the VB Wind uplift resistance with different type of vapor barriers.We design the most e\x13cientthermal barrier for the roofing s tated insu lation, cover board, etc. A modular vege ys-and optimal layouts to ensure January 2025tem. The c s o er board enhances thethem (puncture) and the effects ofmembrane slippage and tearing alongIIBEC Interface15proper water drainage. system consist f pre-grown or precultivated ovvegetation (modules, blankets, or mats), growthE-designresiliency and durability of the sys- heat or solvents when the roof mem- the fastener shank, as shown in Fig. 20 media, a root barrier, pavers, and a drainageEstimationtem. It is installed below the mem- brane is applied (assuming that there(next page), even at low wind uplift system. In industry practice, a VRA is sometimes January 2025braneandabovetheinsulationtois a continuous connection betweenpressures. At high wind uplift pres- IIBEC Interface15 Site Inspectionreferred to as a green roof. However, the termLabor Saving Designs minimize the deterioration of otherthe VB and the membrane at the pe- sures, the barbed plate bends due to green roof can be misleading because it can be CONTACT US FOR YOUR NEXT PROJECT! interpreted differently, as follows:CONCORD | MONTREAL | PETERBOROUGH | SURREY POSISLOPE.COM components during the service liferimeter and openings). Self-adheredthe membrane billowing and losesGreen roof could be a reference to the color oftheroof.Substrateshouldhavemembranes with a tri-laminate facer,its clamping force; the membrane is of the roof (e.g., a copper roof). Green roof is used loosely to denote roofs 18ONTARIO ROOFING NEWSISSUE 1 2025 with environmentally friendly products suchTHE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORNFigure 19. FPR for different deck types. as those made from recycled materials (e.g., bio-based insulations). Roofs with energy-efficient components such as highly reflective roofing membranes (e.g., white single plies or MB roof with reflect ive coating).Based on this, a VRA is defined as intentional placement of an engineered vegetated system over the roof system (Fig. 25).Q14: HOW DOES A VRA RESPOND TO WIND?Figure 20. Fastener plate/membrane engagement against wind uplift in mechanically attachedWind aerodynamics on a VRA can be viewed as roofing system. action, whereas the response of the VRA is the reaction. Not all VRAs react to wind in a similar detached from the deck interface, respectively,barrier. Air intrusion can be a major drivingmanner. The response of a vegetated system as shown in Fig. 22. force for movement of moisture in the formdepends on several factors, such as the membrane of water vapor into a MARS. Fig. 23 showedattachment method, vegetation type, weight, Q12: IS THERE AN IMPACTthe con densation happening below the roofdesign, and installation method (e.g., edge OF AIR INTRUSION ON Amembrane on one of the commer cial roofsrestraint conditions). The complex wind dynamics LOW-SLOPE ROOF? during field investigation. Limiting air intrusionon VRAs can be simplified as effects due to pressure Air intrusion is when the conditioned indooris critical for good roof design practice, it helpsand flow. Responses of the vegetated system to air enters into the building envelope assemblyincrease wind uplift and thermal resistance,flow include sliding, overturning, and scouring and cannot escape to the exterior environmentminimize moisture accumulation and(Fig. 26). Responses of the vegetated system to with the roof membrane acting as an aircondensationissues. wind-induced pressure include fatigue and uplift.16IIBEC InterfaceJanuary 2025'