Screws or nails for securing 2" lumber to overhead joists as fireblocking?

Question

I will be installing fireblocking as part of finishing my basement. I plan to leave about an 8" gap between the newly framed walls (metal stud framing) and the cinder block foundation wall to avoid putting holes into the concrete covering the French drain for my sump pump. I will therefore be installing continuous runs of 2"x12" lumber to the bottom of the floor joists as fireblocking material before framing the walls underneath.

Is it better to use nails or screws to secure the 2"x12" lumber to the floor joists?

Using nails seems like it will work better with the shear loads from expansion and contraction of my otherwise wood-framed house. However, the lumber also has tensile loads from gravity for which screws are typically recommended. I am planning to use non-load bearing metal drywall studs to frame the wall beneath the fireblocking.

Answer 1

2X12 is great, 3/4" plywood would be easier to handle and to drill through when you need to. Chalk your plate line where the wall will go on the room side, rip your plywood to go to the basement wall and 1/4" shy of the chalk line. That way when you set your upper plate you can still see the line to accurately set your wall. To answer your question, using nails will work, it is only fireblocking, you only really need enough to keep it up, since it is not structural, but do it anyway. Screws would work better, especially if it needs to be adjusted after it is up in place, and you see it needs to move a bit, it does happen. Shear or expansion should not be a concern. material usually shrinks once installed.