Problem
My oil burning furnace exhaust/intake manifold does not appear to be sealed properly (daylight and draft visible) from the inside and I wish to seal it.
I also believe mice are getting into my basement through it, as I have recently caught one in a trap near it, and have caught two others in traps near it a few months prior.
Planned solution
My plan is to spray over the hole with great stuff pest block or fire block spray foam and then pack some Xcluder fill fabric over the foam after it has set.
Question
Is the method I laid out a safe way to do this? Some concerns I have are:
- I don’t know if the manifold would get hot enough to ignite the foam or fill fabric.
- I don’t know if there would be a metallurgical reaction between the fill fabric and manifold that would degrade either of them.
- I don’t know if Great Stuff Gaps & Cracks should be used instead of Pestblock/Fireblock.
In the attached image, the area circled in red is the space I wish to spray foam and pack with xcluder fill fabric. Pictured is the manifold, the intake, and exhaust. There is also a sizable gap above the manifold that is not well pictured in this image that I also plan to seal.
