Spray foam insulation not fully encapsulating rafters. Would you guys put this in a report? I’m thinking there will be thermal bridging through the non insulated rafters. New construction home.
Was there a insulation Certificate on site?
1 Like
Very good question I don’t remember seeing one.
Not sure of your location in this state the Insulation Certificate is required by Code to be in a readily accessible area. Normally at the attic access or on the electrical panel.
1 Like
What type of foam was it? Could you poke your finger into the foam?
1 Like
Not very easily, it was pretty tough. Texas requires I report the depth of attic insulation. If its blown-in insulation and there is a certificate, ill take note of that and try to confirm the depth myself with a tape measure. But I always figured I couldn’t verify the stated depth with spray foam (without destroying some anyway), so I just put “Depth of Insulation: Sprayfoam” on the report and I guess I just disregard the insulation certificate.
I used a knitting needle…when important to verify thickness.
2 Likes
I don’t think I would put it in my report. What do you see happening because of thermal bridging here? About the only issue I could see in my state (MN) would be if the attic was conditioned to the point of trying to heat it to 70 degrees in the winter. The bridging could cause snow melting, ice dams, etc. on the roof.
1 Like
just more heat in the attic.
1 Like
thank you, we are in zone 2. right on the cusp
A thermal image would be helpful in supporting your suspicions
1 Like
What you are showing me is very similar to what I see in Zone 3 in GA. I think the minimum is R-19 for us without looking it up in code (more if it is ceiling insulation). That is about what you have there if those are 6" rafters. Thermal bridging is much more of an issue with cold form steel framing. They usually address steel framing a bit differently.
1 Like
thanks, yea it looks like a minimum of R-30 here.
Open cell is 3.5-4 per inch.
1 Like
Thanks, I think I have something.
Exposed framing is very typical. Yes, thermal bridging is present. I’m from far northern MN and your image is a typical practice here. No issues for me with the installation shown.
Closed cell vs open cell: Open cell requires a vapor barrier, is less expensive, but has issues with absorbing moisture and causing problems. Often the vapor barrier is simply a spray on film. Put a warning in your report if it’s open cell. Do an internet search about moisture problems with open cell foam; I’ve seen it firsthand.
2 Likes
For the sake of argument; the r-value of softwoods is approximately 1.4/inch, supposedly.
Wouldn’t that mean that at least the surface area of the exposed framing (presumably approx. 6" thick including the decking) is inadequately insulated?
1 Like
The attic is conditioned, correct? At least it should be if the roof deck is insulated. So it may be a few degrees warmer in there than it would otherwise be. Not a big concern in my opinion.
1 Like
No different than a stud bay filled with batt insulation? 
1 Like