Green Building Advisor Venting Flat Roofs

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.

Green building advisor venting flat roofs.

When installing or repairing a flat roof you must adhere to building regulations. 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. 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.

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. That means the entire perimeter of the roof needs to have air inlets meaning continuous soffit ventilation. So i ll start by saying something that might sound controversial but really isn t.

An air permeable insulation like mineral wool cannot be installed between rafters if the assembly is unvented. 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. Venting of flat roofs.

A qualified roofing contractor will be able to advise on this but here are some of the main guidelines. There must be a slope of 1 80. 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. The room does not have any venting nor is it possible to vent.