b'BUILDING CODEOther roof systems for Part 3 buildingsIn the previous articles of this series, we dealtexclusivelywithsheetmembrane roofsandwind-resistantdesignsfor so-calledPart3buildings.Butwhat aboutotherroofsystems,likethose securedwithballast?Whatshoulda designerconsiderforliquid-applied membranesthatareexposedtothe weather?Whataboutwater-shedding roofs? Does the building code offer anyA poorly attached membrane roof that succumbed to wind on a Part 9 structure. Membrane roof guidance for these when specified for arequirements in the Building Code apply equally to Part 3 and Part 9 buildings. Credit: M. Aase.Part 3 building?The answer is not simple. In general, thebuildingcodeappearstobeless Roof Consultingconcernedwithmeansandmethods, andmoreconcernedwithoutcomes like resisting the ingress of precipita-tion, water or moisture from the exte-rior or from the ground (Division A, Article3.2.1.1.,FunctionalStatements). For example, Division B, Part 5, Article 5.6.1.2., Installation ofProtective Materials, addresses resistance to precipitation for Part3buildings.However,theentire subject is covered in a single, somewhat vague sentence: Where protective mate-rials are applied to assemblies to provide the required protection from precipita-tion, they shall be installed so as to shed precipitationorotherwiseminimize MIND THE GAPS its entry into the assembly and prevent itspenetrationthroughtheassembly. Thats it. Outside of the requirements in Division B, Article 5.2.2.2., and beyond what is addressed in Division B, Part 9, nothing is said about how to conform to that statement. In fact, more is said about roofinginPart9thanforanyPart3 building, including buildings classified as post-disaster structures. This is a regret-table shortcoming of the building code. Roof Condition Assessments & SurveysRoof System Design & Contract ManagementThesegapsinthebuildingcodeGreen Roof Designadmittedly leave the reader with manyWarranty & Maintenance Reviewquestions and considerable uncertainty.Infrared ThermographyFor example, to what standard shouldRoof Access & Fall Protection - Design & Testingasphalt shingles be installed to achieveRoof Asset Management & Capital Planningthe intent of the codes functional state- RCABC Approved Observersments when the building is classified as a Part 3 structure? How do you design aballastedrooftoconformtotheCreative Thinking Practical Resultsbuilding code? These, and other ques- Vancouver & Surrey 604-738-0048 Victoria 250-386-7794tions like them, are utterly valid and haverjc.cato be asked. Nanaimo 250-716-1550Kelowna 778-738-1700www.rcabc.org l17'