Green Building Advisor Venting Flat Roofs

So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus.

Green building advisor venting flat roofs.

There must be a slope of 1 80. The flat roof overhead is framed in full depth 2x6s finished with what jordan believes is roll roofing a type of asphalt roofing. Originally published may 1976. That means the entire perimeter of the roof needs to have air inlets meaning continuous soffit ventilation.

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. Musings of an energy nerd. Wash the underside of the roof deck with air. If you are planning to install mineral wool insulation on the interior side of the roof sheathing you will need to include a ventilation channel between the top of the insulation and the underside of the roof sheathing.

An air permeable insulation like mineral wool cannot be installed between rafters if the assembly is unvented. If you re actually going to vent the roof let s be serious about venting the roof. Part h of the building regulations regarding drainage state that water should drain to one or two edges. When installing or repairing a flat roof you must adhere to building regulations.

A qualified roofing contractor will be able to advise on this but here are some of the main guidelines. The room does not have any venting nor is it possible to vent. So i ll start by saying something that might sound controversial but really isn t. 2 if you re going to vent the roof then vent the roof.