b'Current building code requirements and typical design and construction practices for these structures do not always provide for adequate ventilation of attic spaces.Thefollowingarticleorigi- leya professor at the University nallyappearedintheFebruaryof Minnesota and the president of 2024 issue of IIBEC Interface. Itthe American Society of Heating is reprinted here with permissionand Ventilating Engineers (ASH-fromtheInternationalInstituteVE), which is currently known as I nMontreal,Que.,low-riseRefrigerating and Air-Condition-of Building Enclosure Consultants. the American Society of Heating, residentialbuildingswithing Engineers (ASHRAE)con-low-sloperoofsystemsareductedroofventilationresearch animportantpartoftheusingspecimensintheformof citysarchitecturalcharacter.small-scalehousesthatclosely However,thecurrentbuildingresembled the size and shape of coderequirementsandtypicaldoghouses. The test specimens in design and construction practicesthe doghouse experiments were forthesestructuresdonotconstructedwithslopedroofs alwaysprovideforadequateand were similarly prepared and ventilationofatticspaces.Thisconstructed without vapour bar-articleexplainshowthecurrentriers. The only difference between coderequirementswerederivedthe specimens was the amount of and uses case studies to illustrateventilation allowed into the attic ventilationproblemsandthespace. The first specimen had no repairstrategiesemployed.roof ventilation, while the other Adequate Ventilation ofCollaborativeresearcheffortstotwo specimens were constructed addressgapsinourknowledgewithventratiosof1/288and andprovidebetterguidanceto1/576, respectively. (A vent ratio architects and building enclosurerepresentstherequiredareaof Low-Slope Roof Systems: professionalsarealsodescribed.openingsprovidingexteriorair Low-sloperoofsystemsrefertointo the roof cavity per horizontal aroofsystemwithaslopelessroof area.) These test specimens than 1:6 and are commonly calledwerethensubjectedtointerior flatroofs,suchasthroughoutand exterior conditions similar to this article. residential dwellings under typi-Historical Context cal winter conditions, and at the Theintroductionofthermalconclusionofthetest,onlythe insulationforresidentialhous- house with a vent ratio of 1/288 ing in North America in the laterevealednotracesofcondensa-1920sandearly1930screatedtion or frost formation.condensationissues,mostnota- Rowley,AxelB.Algrenand bly within wood-framed residen- Clarence E. Lund later completed tialdwellings.Typicalsignsoffull-scaletestsyieldingsimilar condensationwerenotedintheresultstothedoghouseexperi- Viana Roong & Sheetmetal Ltd. is a progressive roong, form of peeling wall paint and wa- ments. 2 Aspartoftheseriesofwaterproong and restoration company who has successfully terstainingwithinupper-storeyfull-scaletests,atestspecimencompleted thousands ofprojects over the past37 years. ceiling finishes. Eventually, thesewas also evaluated with a flat roof issuesweremostlycontrolledconfiguration.Thetestcondi- Our services include all types of roong, sheetmetal and siding,through the installation of vapourtionswereanexteriortempera- caulking work, waterproong and more.barriers within walls and roof sys- ture of -10F (-23C), and interior tems;however,problemswithinair at 70F (21C) and 40-per-cent someroofatticspacespersisted.relative humidity (RH). In gen-Researchersinthemid-tolateeral,various-sizedventilation 1930s indicated that the installa- openingsandtypeswereevalu-tion of a vapour barrier was some- atedfortheroofcavityunder times not sufficient to reduce theconstant test conditions and the potentialforcondensationandsame building configuration. Ac-that the ventilation of attics andcording to their findings, light roof cavities was necessary. 1 frostaccumulationsweretypi-However, the appropriate ap- cally noted within the roof cavity74 Advance Road, Toronto|416.763.2664|vianaroong.comproach to ventilation of the roofspaces regardless of whether roof space remained ambiguous untilventilation was provided by side 1939, when Professor Frank Row- wall or roof openings.ORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 1 202415'