Replies

1. Expert Member
   BILL WICHERS | Feb 10, 2022 09:16pm | #1

   I would probably use canned foam around that box perimeter, then use some red silicone high temperature caulk (not the intumescent "fire stop" caulk).

   I'm not sure what you're asking about with spray foam between sections and falling out. Spray foam shouldn't fall out. Aerobarrier is better at sealing small gaps than big holes. Can you elaborate a bit as to what you're trying to do?

   Bill

1. 
   John_Y | Feb 11, 2022 12:11pm | #5

   Thanks Bill

2. 
   charlie_sullivan | Feb 10, 2022 10:31pm | #2

   Where is that second picture? Is it looking up or down? What's the space above and the space below?

1. 
   John_Y | Feb 11, 2022 12:12pm | #6

   Second picture is floor boards of the original house. It is looking down on them. Above will be engineered hardwood in the future, below is a vented crawl space.

3. 
   user-5946022 | Feb 10, 2022 11:15pm | #3

   If the second photo is of floor boards, you are much better off sealing the crawl space below and making it a conditioned crawl. Also, I think I would put a layer of 1/2" ply wood over those boards.

1. 
   John_Y | Feb 11, 2022 12:14pm | #7

   Thanks CL,

   Putting 1/2 inch plywood over would mean either a 1/2 inch step down to the rest of the house (single story) or 1/2 inch ply on the rest of the flooring ~1400 sq ft of additional floor area.

   I guess I could rip out the old floor boards and put new 1/2 inch ply but thinking there are more cost effective ways to do this.

4. 
   DirkGently | Feb 11, 2022 09:33am | #4

   I sealed gaps in 1x6/1x8 sheatbg boards with foam gun (amazon $20) and blue can window and door (much more flesxible). Get yourself the great stuff disposabe tips which fit on end of foam gun which allows it to fit into tiby cracks. I had great success and it has been 5 years now.

1. 
   John_Y | Feb 11, 2022 12:34pm | #8

   Thanks Dirk!