New construction. I don’t see this often. Is there anything I should tell the buyer to be aware of?
The garage attic was the one place where it was insulated on the roof deck as well as on the ceiling drywall.
No problems with sweating in summer?
Not if it is conditioned.
Read this article: Open cell foam & moisture
A few years ago, I consulted on a home that had severe ice dam issues and was insulated with spray applied open cell foam. This was a tight, energy efficient home with a combination vaulted ceiling roof and a conditioned attic roof. The spray on vapor barrier appeared to have lost its effectiveness or may have been missing.
There are reported issues of roof sheathing rotting because of moisture movement through the foam due to an ineffective moisture barrier. IMO, a fully sealed moisture barrier is critical for this type of insulation.
As a retired builder, I would never utilize open cell foam insulation for construction clients. I live in a cold climate. I don’t know the “on the ground” experience in moist, humid and warm climates.
Get on the internet and search “open cell foam sheathing rot and problems”. Decide yourself how you are going to advise your client.
Was there any ventilation noted?
Spray foam insulation on the roof requires the space to be conditioned. There needs to be a register and return, if it’s a large space might need 2.
Who requires this?
He’s saying the application itself requires dehumidification by means of air conditioning including adequately-sized supply and return ventilation, which is correct.
Who requires this?
Perhaps. I think it is good building practice to condition the space. However, I have not been able to locate a requirement from any source. I would also like to find a credible source such as the manufacturer, trade organization, etc. to support any recommendation I may make to condition the space.
I do not know of any off hand, but if it is, it’s likely a “Local” requirement.
There are several variables to take into account to determine whether or not supply air from the HVAC system is required. R806.5 of the 2021 IRC addresses unvented attic requirements.
Most of the ones down here are not conditioned.
Thank you for the information.
If the roof is shingled it will reduce the manufacturers years of warranty.
You’re welcome.
‘Unvented attics,’ rightly or wrongly, are often referred to as conditioned when they are part of the house that is heated and cooled, conditioned, and when insulation is applied a top the roof deck, directly under or/and directly on top which is a combination of both. Note: Unvented attics do not always have to be conditioned.
Some of you are starting to sound like Biden’s alphabet soup, when you strain too hard to rationalize away the basic need to remove intrinsic heat and humidity from an encapsulated space that has by definition become an extension of the conditioned space.
