Unvented Cathedral Ceiling with Beams – Worried about Risk of Exposure to Insulation Particles
Hello, I’m a homeowner (not a builder) that is hoping for insight from the experienced builders on this forum to help put my mind at ease.
In 2022, I purchased a new construction home in Redmond, Oregon (climate zone 5). The house has a modern design which involves a great room ceiling that is continuously sloped from one wall to the other. There are several 6×12″ wood beams that span across the ceiling, running in the same direction as the slope, and emerge to the exterior eaves. There is no attic above the ceiling or beams. The exterior roof line parallels the ceiling, with about 12″ between them (as viewed from the outside). Notably, there aren’t any intake or soffit vents on the exterior eaves. So, I believe this is what is known as an “unvented roof assembly with cathedral ceiling”.
Here is my concern: when I look at the ceiling, I can see small gaps (up to about 1/8″) along the length of some of the beams where they meet up with the ceiling drywall. I worry that these gaps could provide a passage for insulation particles to enter into the living room. To be clear, I do not know what insulation is on the other side of the drywall, but other homes in the neighborhood use batt insulation. For the sake of this discussion, let’s assume it’s batt insulation. My understanding of the building code (IRC section R806.5 #2) for unvented cathedral roof assemblies in climate zone 5 is that air/vapor plastic retarders are not allowed on the ceiling side, so as to allow drying of any moisture from the interior. If so, would this mean that the aforementioned gaps could in fact be a passage by which insulation particles could enter into the living space? Or would there be some sort of barrier between batt insulation and the ceiling drywall, even with an unvented roof assembly?
I’d greatly appreciate insights from the experts on this. I haven’t been sleeping well lately because of the fear that insulation particles could be entering the great room from above. I realize that the presence of a passage wouldn’t necessarily mean that particles are coming down, but nonetheless, I would very much prefer there was zero opportunity for them to enter so that I don’t even have to wonder.
Also, please let me know if I can provide any additional information.
Thank you so very much!
Sarah
Replies
How is the drywall finished where it meets the beams? The right way to do this would be to use L metal on the edge shoved tight against the beam, which might leave gaps as the wood moved or shrank. It's possible it was just taped next to the beam. In any case you should be able to caulk this gap with. high quality flexible caulk. If you want you could then use a moulding to cover this corner.
To finish drywall where it meets beams, the recommended approach is using L metal snug against the beam, although this may leave gaps if the wood moves or shrinks. Alternatively, tape may have been used. You can fill any gaps with high-quality, flexible caulk. Optionally, adding molding can further cover and enhance the corner.
Now there’s a new novel idea. Move a few words around and bingo.
You are one slick cookie.
Thanks