Karl Waldeck
2/6/2011
I will be roofing an A-frame built in '73 with a 60 degree pitch (18/12). However, I found that there is currently no soffit venting or airspace except for the gable vents in the attic. The roof rafters and sheathing are essentially treated like insulated exterior walls until they reach the attic. There is a vapour barrier on the inside. Should I leave it as is, or place the panels on strapping to provide some airspace (and ventilate somehow)?
Info @windowsonwashington.net
An informed customer is our best customer.
2/6/2011
Have they had issues in the past? Above deck venting will help lessen the transference of heat into the living space on the sections not in the attic. If they have radiant heat issues on those outside wall/roof sections, you could cover the roof in a rigid foam to add insulation to the structure. Putting the roof down on battens or strapping and providing and air space to vent over deck will help as well.
Karl Waldeck
2/6/2011
Thanks, Currently the roofing is cedar shake ... and is difficult to determine if heat/vapour is escaping (although snow isn't melting excessively fast). I'd hope that the 60 degree pitch would limit stack effect on the roofing (meaning heat would push up to the narrow vented attic space). Above deck venting could definitely help with vapour escape. Thanks for the advice. Karl
Info @windowsonwashington.net
An informed customer is our best customer.
2/6/2011
The shakes are tough because they can hide a great many issues when it comes to heat loss between their insulation value and the ability to store and release moisture. The over deck idea can't hurt.
Todd Miller
Classic Products, Inc.
2/9/2011
Shakes breathe a great deal. I would suggest adding some ventilation when they are replaced with metal. Curious ... what type of metal roof do you plan to use?
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