Here’s a video we made of us testing accuvent cathedral baffles. Pretty fun day, but we’re probably not going totally viral with this one. Nevertheless, building geeks might find it interesting.
Prior to the test, I really thought that the baffles would crumble. Not the first time I’ve been wrong.
You may notice a little bit of cellulose seepage on to the vented side of the baffle. Probably nothing to be concerned with, especially considering the test wouldn’t allow for the mechanical fastening of the baffle into the chamber. But regardless, I think it’s worth addressing. Here are a few tips for dense-packed, vented rafter cavities:
1) When installing the baffles, start at the ridge and work your way down, overlapping the baffles as you go. This will direct water leakage out of the cavity and into the soffit. Tell the homeowner to periodically check for signs of water leakage in the soffit.
2) Consider sealing the perimeter of each baffle. We use a single part foam, which is fairly inexpensive.
3) Cellulose is incredibly versatile. We use National Fiber (website here), which makes an all borate blend of cellulose. Make certain you’re obtaining a density of 3.5 lbs/cf. More on the guys at National Fiber for another entry.
4) We buy Accuvent baffles from Wind-lock (website here), another great company. Depending on the application, accuvent makes a variety of baffles, some of which work well on conventional retrofits.