I'm putting a bathroom in upstairs. I sistered the joists (red arrows), but there is a 2×4 (blue arrow) laying flat directly above a wall that is between the downstairs office and the dinning room. It's not laying on lath though. It's up ~1/4" because these pieces (blue arrows) are holding it up 1/4".
What is this 2×4 for that is seemingly hovering over the top of the downstairs wall, and can I cut out 12" to run a drain past it?
Best Answer
If there is a wall directly below it is most likely the "top plate" that the walls studs are nailed to. If there are no studs attached it then is most likely a "stiffener" for the wood lath underneath it. In this case it would be keeping the lath strips in-line and level in order to prevent bouncing or flex. It has been installed there with a purpose unless you can install a substitute piece to replace the board leave it until you verify what purpose it serves.