b'ELECTRICAL CODEitsuccessfullyresiststhosepressures. 9That is never done with mere guesswork; proven, tested methods are required by the Building Code, because properly securing the roof system to the building is a matter of both public safety and building occu-pantcomfortandhealth.TheBuilding Codedoesntspecifyhowamembrane roof system must be secured; it only spec-ifies how one can be sure the methodsare reliable.A newly constructed membrane roof system may use screw fasteners, adhesives or a combination of the two. When screw fasteners are used to secure all or part of the system, their placement must precisely follow a tested or proven pattern, or the roof may fail in a windstorm. One roofing membranemanufacturerIknowof tinkered with the number and placement of mechanical fasteners on one of theirFigure 3: Mechanical fasteners penetrating the underside of a corrugated steel roof deck. The circle indicates a fastener that has highly successful tested assemblies to testpenetrated the electrical conduit branch near the junction box.the viability of an alternate pattern. The(Photo: RCABC files)test failed miserably. orremovedandreplaced,dependingprecise placement of screws is essential Subjected to the harshest of conditions,oncircumstances)bysecuringnewfor the performance of a roof system a roof has a limited lifespan. Eventually, atroof materials with roofing screws and(neworrenewed),theinstallationof least some of the roof must be renewed.plates. Why use roofing screws? Becauseelectrical systems beneath the structural Electrical systems, on the other hand, areregardless of the bonds between mate- deck can conflict with the building code permanent.Nooneevercontemplatesrials in the existing roof system, screwsor the specified roof design. When elec-renewing their electrical system; it may befasten the entire in situ assembly to the trical systems are concealed inside spray added to, but it will never be removed andstructural deck. insulationorobscuredbehindceiling replaced because it is worn out. Roofingscrewsaremadetobe8 See my article on the subject of wind uplift inAs a roof system ages, so do the linksself-drilling,andtheyareveryeffec- Roofing BC, Vol. 18, No. 2 (Summer 2021).between each of the materials. When muchtiveatdrillingthroughwoodorsheet9 I use the term roof as shorthand for theof an existing roof system is in service- steel. For a screw fastener to work, itsystem of materials that protects a building able condition and it is time to renew themust penetrate into or through a struc- from the weather. It is not used here to denote the roof structure. I am also using the term to membrane, the designer may find it nextturaldeckbyatleast19mm(3/4).focus specifically on flat roofs that are typically toimpossible(apartfromdestructiveHowever,electricalconduit,junctionwaterproofed with a sheet membrane system.testing) to assess the integrity of connec- boxes or light fixtures are often installed10Installation inside the roof assembly is notions between materials, particularly wheredirectly beneath or even inside the rooflonger permitted by the Canadian Electrical adhesives were used. In that case, the oldassembly,sometimesbeforethefirstCode, Part 1 (Rule 12-022), but this hasnot yet been adopted by the Province ofmembrane can be renewed (left in placeroofsystemisinstalled. 10 BecausetheBritish Columbia.Bothwell-Accurate has enjoyed 90 successful years in business and now employs over 500 professionals to meet all your waterproofing, architectural metal and roofing project requirements. With a management team that represents some ofthemostexperiencedprofessionalsintheindustry,andmorethan60,000 completedprojects,weareoneofCanadasoldestandmostexperienced construction firms. We proudly service our growing roster of industrial, commercial and institutional clients proving innovative, superior installations in the lower mainland and interior of British Columbia and across Ontario.604-282-7960bcestimating@bothwell-accurate.combothwell-accurate.com32 lROOFINGBClFALL 2022'