How important is attic ventilation with an attic radiant barrier system?
Ventilation is very important because this is the primary method used to get rid of the heat that is being stopped by the radiant barrier. In climates that require a lot of cooling, it is recommended that attic ventilation at the top of the attic meet or exceed the Uniform Building Code recommendations of 1/150th of the attic area. The UBC also specifies 1/600th at the eaves/soffits of the roof. It is recommended that this be at least 1/200th of the attic area. The UBC’s attic ventilation requirements are directed toward preventing moisture condensation problems but they are equally valuable to hot climate homes that need to get rid of the heat absorbed by the roof. It is the opinion of this site that venting codes are not sufficient for hot climates as they are designed for moisture egress, not sufficient exhausting of super heated air.
• Ventilation is very important because this is the primary method used to get rid of the heat that is being reflected by the radiant barrier. In climates that require a lot of cooling, it is recommended that attic ventilation at the top of the attic meet or exceed the Uniform Building Code recommendations of 1/150th of the attic area. The UBC also specifies 1/600th at the eaves/soffits of the roof. It is recommended that this be at least 1/200th of the attic area. The UBC’s attic ventilation requirements are directed toward preventing moisture condensation problems but they are equally valuable to hot climate homes that need to get rid of the heat absorbed by the roof. • Sheets of radiant barrier are very difficult to install in existing attics. It is also difficult to get a good installation because of the difficult working conditions of extreme heat in the summer, low headroom, numerous roof framing or truss webs in the way, and low light conditions.
