Green Building Advisor Venting Flat Roofs

Musings of an energy nerd.

Green building advisor venting flat roofs.

Part h of the building regulations regarding drainage state that water should drain to one or two edges. 2 if you re going to vent the roof then vent the roof. Venting in building construction as a technique of cooling by air flow and of controlling or removing moisture has been in use for many years. So i ll start by saying something that might sound controversial but really isn t.

Venting of flat roofs. That means the entire perimeter of the roof needs to have air inlets meaning continuous soffit ventilation. There must be a slope of 1 80. A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.

An air permeable insulation like mineral wool cannot be installed between rafters if the assembly is unvented. The room does not have any venting nor is it possible to vent. Wash the underside of the roof deck with air. The flat roof overhead is framed in full depth 2x6s finished with what jordan believes is roll roofing a type of asphalt roofing.

He says ruling out a layer of exterior rigid foam. If you re actually going to vent the roof let s be serious about venting the roof. Originally published may 1976. A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science.