b'Technical Articlecontentsisminimalinextentandtems(PARS)andmechanicallyat-minor in cost. Resiliency index 2 istachedroofsystems(MARS).AnClimate Category Resiliency Index 1 Resiliency Index 2 Resiliency Index 3for any level of performance require- AARSinvolvesusingadhesivesto mentbetweenResilienceIndex1bond the roofing layers, mainly theNormal Bronze Silver Goldand 3. The user should select the re- cover board and insulation, on to siliency index based on the expectedlower layers. A PARS involves us-function of the building (especiallying a combination of adhesive andSevere Silver Silver Goldimportancecategoryandrisk)andmechanical fasteners to secure the theresiliencyrequiredintermsofroofing system to the substrate. InExtreme Gold Gold Goldrecoveringfromdisturbancesanda MARS, the roofing system is se-adaptingtoclimateseverity.Aftercured to the substrate with mechan-the resiliency index for the projectical fasteners such as screws or nails.Figure 9: The application of climate category and resiliency index to identify a roofing assemblys performance level.is selected, the tool produces a sum- CSA A123.26 5does not address the maryofdesignparametersfortheclimaticadaptationrequirementsTable 1: Wind load determination for Toronto using Climate-RCI, 13Ontario.project,includingrequiredroofforthestructuralsupport(deck) performance level, whether Bronze,belowtheroofassembly,whichClimateRequired Silver or Gold. shouldbehandledthroughen- Global WarmingSeverity forWind PressureFactored Wind UpliftResiliencyPerformance When the combination of climatehancements to the structural designMagnitude Wind Value Load Index Level for Windindex and resiliency index identifies aof the buildings.Bronze-level roofing system for the entered inputs, the performance re- Resistance to Wind UpliftSource: Climate-RCI 13 Source: Wind-RCI 7 Source: Climate-RCI 13quirements are the current NBCC 2 Loadsand NECB 12requirements, and theUsing Climate-RCI, 13by input- 1 Bronzeproject-specificwindupliftvaluesting the project location and globalCorner -2.6 kPacanbedeterminedusingWind- warmingmagnitude,designerscan0.5C Normal 0.44 kPa Edge -1.3 kPa 2 SilverRCI. 7 Whentheroofingsystemisdeterminethequalitativesever- Field -1.0 kPaclassified as Silver, it is assumed thatityoftheanticipatedfuturewind3 Goldthe roof assembly will comply withconditions as either normal, severe theNBCC 2 andNECB 12 require- or extreme and a quantitative 1/501 Silvermentsaswellassomeadditionalhourly wind pressure. For instance,Corner -2.7 kParequirementsspecifiedinCSAthe severity and wind uplift pressure2C Severe 0.46 kPa Edge -1.4 kPa 2 SilverA123.26. 5 Similarly,incaseofthevalue for a project located in Toron-Goldperformancelevel,theroof- to (City Hall) with a global warm- Field -1.1 kPaing assembly must meet the Bronzeingmagnitudeof2Cissevere3 GoldandSilverlevelrequirementsplusand 0.46 kPa (9.67 psf) respectively. additionalrequirementsspecifiedFor the same location and a global1 Goldin CSA A123.26. 5In the event of awarmingmagnitudeof3.5C,theCorner -2.9 kPaconflict in requirements between theseverity is extreme and wind pres- 3.5C Extreme 0.5 kPa Edge -1.5 kPa 2 Goldlevels, the requirements of the high- sure value is 0.50 kPa (10 psf). TheField -1.2 kPaest level would take precedence. Fig- wind pressure value is then used to3 Goldure 9 illustrates the various relation- calculatethefactoredwindloads ships between the climate categoryeither following the procedure out- Note: Above values are for a roof with no parapet.and resiliency index in the selectionlined in section 4.1.7 of NBCC 2or of the required performance. using Wind-RCI. 7It is to note that CSAA123.26 5 isapplicabletherequiredperformancelevelforselectionofresiliencyindex.Tableof corner: -2.2 kPa; edge: -1.3 kPa;uplift loads. Installation of a roof toadhesiveappliedroofsystemsthe roof, whether Bronze, Silver or1 presents the wind uplift pressuresand field: -1.0 kPa. While the pres- parapet as an extension of the main (AARS), partially adhered roof sys- Gold,mayvarydependingonthedetermined for a hypothetical build- ence of a parapet reduces the windstructuralsystemposeschallenges ing of 9 m (30 ft.) height in Torontouplift loads within the roof area, theinachievingcontinuityoftheair (CityHall),anditscorrespondingwind loads against the parapet clad- barrierattheintersectiondetail factoredwindupliftloadsandre- ding and its components, particular- between the exterior wall and roof quired performance levels for differ- ly the top edge of the parapet, will beassemblies. Lack of air barrier conti-ent resiliency indices. higher and is to be determined. Fornuity may contribute to wind uplift instance, in the above scenario, thefailures in addition to the potential Wind Uplift Resistance atfactored wind loads for parapet clad- condensation issues within the par-Think Safe, Corners and Edges dingandmetaledgecomponentsapet assembly. Hence, the roof-to-Work Safe, Thepresenceofroofparapetswill be -2.9 kPa in suction for cornerexteriorwalljunctiondetailingat since 1988 can significantly minimize the effectand -1.7 kPa in suction for edge, andthe base of a roof parapet installed of wind load at the roof perimeters,a positive load of 1.4 kPa at the faceas part of the main structural sys-i.e. corners and edges. When calcu- of the parapet. temrequiresspecialattentionto Top-Line Roofing & Sheet-Metal Inc. specializes in the installation, repair, and maintenance oflating the factored wind uplift loadsFortheSilver-andGold-levelensure that the continuity of the air industrial roofs throughout Southern Ontario.per NBCC 2or using Wind-RCI 7toroofs,thevaluesdeterminedarebarrier is maintained.OUR SERVICES: meet current code (Bronze level), therequired to be increased by 30 perInadditiontotherequirement Commercial roofing Re-roofing presence or absence of a parapet iscent and 50 per cent respectively ifto either install a 0.9-m (3-ft.) high Roof maintenance Skylight installationRoof inspection,Sheet metal flashing,one of the factors in determining theaparapetisnotinstalled.Table2parapet or increase the performance evaluation & report fabrication & installation project specific requirements. For in- presents the wind uplift values forrequirements to counter the higher Historical restoration Retro-fit curb installation stance, for the above Toronto exam- each of the performance levels forwindupliftloadsfortheroofpe-Emergency roof repairs ple, the factored wind uplift loads forthe above example.rimeters, CSA A123.26 5includes a the roof assembly with no parapetThe alternative option of install- requirementtoreinforcethefield (905) 602-0760 are corner: -2.6 kPa; edge: -1.4 kPa;ing a 0.9-m (3-ft.) high parapet mustmembrane termination using metal 1325 Fewster Dr and field: -1.1 kPa. The same roofbeinstalledasanextensionofthebars or plates with a maximum spac-Mississauga, ONL4W 1A2toplineroofing.ca with a 1-m (3-ft.) parapet will havemain structural system of the build- ingof152mm(6in.)toprovide reduced factored wind uplift valuesing and meet the determined windsecondary protection against mem-18ONTARIO ROOFING NEWSISSUE 3 2025 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'