u/Affectionate_Cap_266

How do I go about proper fire blocking above this wall?

Ive scoured the internet and I cannot for the life of me find a straightforward answer.

I truly have been doing plenty of reading and looking at pictures, and trying to understand how to apply it to my build.

What I do not understand is whether or not the blocking runs parallel to or perpendicular to the wall below it. And, if I’m using the foam board as part of the fire block assembly, that doesn’t make sense to me because it’s super flammable, so wouldn’t it just burn up and create a void for the fire to spread anyway? 

Just confused on how to apply all the information that’s out there. I know it should be “standard”, but you all know as well as I do that nothing ever matches exactly what you find in books, on the internet, or in pictures. 

https://preview.redd.it/1apfftvl44ah1.jpg?width=5712&format=pjpg&auto=webp&s=113cc2565908058595ff345a8cea97d1722e1a3c

https://preview.redd.it/cm2sctvl44ah1.jpg?width=4284&format=pjpg&auto=webp&s=ccc52e6864f5e4131b0255fae1f434f4968a5f73

https://preview.redd.it/mjvqmsvl44ah1.jpg?width=5712&format=pjpg&auto=webp&s=bde2331d39458d8e849024d85314b072de1506f9

https://preview.redd.it/3ltdctvl44ah1.jpg?width=4032&format=pjpg&auto=webp&s=55ac59e018d500527e76867373a7b219c2297048

How do I go about proper fire blocking above this wall?

Ive scoured the internet and I cannot for the life of me find a straightforward answer.

Behind the last true floor joist is a cavity above the concrete foundation, on the other side of it is the rim joist. The builder stuffed fiberglass insulation up there, but there is absolutely no way to get rigid foam board up there or air seal around it with spray foam.

Would it be acceptable to just run a single sheet of rigid foam from the concrete floor, all the way up the wall, and past the gap circled in blue and then seal that cavity in there with the fiberglass still in there? Essentially just moving my air seal one joist cavity in, instead of right agains the rim joist?

https://preview.redd.it/e10fi025563h1.jpg?width=2100&format=pjpg&auto=webp&s=75d82c70c8fd0fa1eef3848c4c9e44b5099de6ea

Behind the last true floor joist is a cavity above the concrete foundation, on the other side of it is the rim joist. The builder stuffed fiberglass insulation up there, but there is absolutely no way to get rigid foam board up there or air seal around it with spray foam.

Would it be acceptable to just run a single sheet of rigid foam from the concrete floor, all the way up the wall, and past the gap circled in blue and then seal that cavity in there with the fiberglass still in there? Essentially just moving my air seal one joist cavity in, instead of right agains the rim joist?

https://preview.redd.it/e10fi025563h1.jpg?width=2100&format=pjpg&auto=webp&s=75d82c70c8fd0fa1eef3848c4c9e44b5099de6ea