How do you Fireblock this?

I am building the walls our of steel studs and the inspector wants this fireblocked so the fire can't go into the bays above it. I have attached a diagram of what the inspector is looking for, in the diagram look at the lower left hand side call perimeter basement walls. I have also attached a picture of my framing in my basement and the problem I have having is the joists are sitting on two sill plates so they are raised off the concrete block 4". What is the best way to fireblock this?

 

Install a strip of 3/4 (nominal) OSB to the underside of the joists, installing blocking if needed. The OSB butts against the sill plate and extends to the where the inside edge of your wall top plate needs to be. The OSB will be between your top plate and the bottom of the joists.

You want to caulk the seam between the OSB and the sill plate with firestop caulk, and any penetrations for wires or pipes need to be caulked with firestop caulk or stuff tightly with mineral wool, like Roxul. Seams in the OSB have to be underneath joists or covered with another small piece of OSB.

Here's a good reference on firestopping with pics:

How to Firestop Your Basement | Contractor Kurt

 

Can the firestop run up to the top plate or does it need to run underneath it all the way flush to the other side. In the picture I attached and the site you showed me it ran underneath the top plate? I am using steel track as my top plate to connect to the steel studs but didn't know if that mattered or not.



When I do my horizontal Fire stops every 10 feet can I use another steel stud and just foam the holes in it so there isn't any gap between the foundation wall an sheetrock? Every description I see shows wood studs and steel studs aren't listed in the approved material?

Thanks

 

IMO the best way would have been to top out the area before the wall was built. This means putting a strip of drywall on the ceiling before the top plate was installed. That strip blocks the space above and behind the top plate.

 

You might be able to do the things you ask about, but only your inspector can green light them so I suggest discussing with him/her.

 

just stick a piece of sheet rock there. no need to remove the new wall and put it under the top of your new header also. Some places they won't make you caulk the voids with the pricey red fireproof caulk, you can just use Fire Resistant Stone Wool Insulation aka rotten cotton, but it's hard to find without buying the whole bail, some lumber yards will sell single pieces though. You tuck that in the voids. The drywall firestop might need to be 5/8" thick but 1/2" or 3/8" should be also okay for code.
For your vertical (not horizontal you said by mistake) firestops every ten feet at all corners and ends, just stick a piece of drywall there. Basically get it as tight to the wall as you can and then rotten cotton if there's a void. Might be easier to do in section if a protrusion on the wall is throwing the whole piece off. then screw it to the 3.5" side of the steel stud and make sure it doesn't stick out to interfere with the actual drywall that will go on the walls.