*
I am considering a skylight for my vaulted ceiling. The A-frame roof has 24″ on center trusses and the fiberglass insulation has the vent channels installed to provide the 1″+ air gap between the sheathing and the insulation. Question: If I install the standard 21.5″ wide skylight, won’t the framework essentially block off any air vent flow between those trusses? The vent channel is unable to continue up to the attic. I have read lots of statements on the importance of this vent channel (shingle life, ice dams, etc.) Just wondering if I am missing something or if anyone has a work-around? Thanks.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
The FHB Podcast crew offers expert advice on choosing the right insulation for the roof of a small, balloon-framed home.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
Fine Home Building
Follow
-
Fine Homebuilding
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial Now -
GBA Prime
Get instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
*
The vent channels are not important at all. What is important is making sure that your ceiling is airtight so that hot air doesn't leak right through and hit your roof.
Skylights are notorious prformance problems because they are not supported in conventional roof venting wisdom. Some guys drill holes, or nothch rafters, or box out the skylight with thinner material. The end result is that there wasn't a whole lot of airflow through there to begin with and ANYTHING in a clear vent channel makes it worse. The tricks don't help get the air through.
So... Make the roof airtight, which includes the boxout for the skylight, and caulk the drywall to the skylight jamb or extension. MAKE THIS ASSEMBLY AIRTIGHT! No tongue and groove boards in this area, unless airtight drywall is under them.
Recessed lights and electric boxes are also other big leakers of hot air into the roof assembly.
-Rob
*
I am considering a skylight for my vaulted ceiling. The A-frame roof has 24" on center trusses and the fiberglass insulation has the vent channels installed to provide the 1"+ air gap between the sheathing and the insulation. Question: If I install the standard 21.5" wide skylight, won't the framework essentially block off any air vent flow between those trusses? The vent channel is unable to continue up to the attic. I have read lots of statements on the importance of this vent channel (shingle life, ice dams, etc.) Just wondering if I am missing something or if anyone has a work-around? Thanks.