Curious when it comes to partition walls. In my house which is a year old I have 23’ 8” webbed floor trusses spaces 24” OC accross the entire second story. There is deflection of the floor system which I would expect. However all of the partition walls make noise when walking around. Not only from the base plate where it’s nailed into the floor trusses. But in the middle and top. Nail popping sounds. They are tightly nailed and I have found that because the floor is moving under load so is the wall, which pops the nails holding it together. This happens all across the upstairs.
What was the intention? Partition walls are supposed to deflect with the floor? I believe they are but then how can one prevent these noises aside from decoupling the walls from the floor?
Replies
You may find it necessary to reduce the deflection of the floor. Have an engineer tell you if and how much of the floor trusses can be 'boxed' in with plywood panels to stiffen them. The roof would need to flex too and I suspect there is added stress on the walls and bottom chord of the roof (upper) trusses. Partition walls are a vertical system and in direct conflict with the (horizontal systems) floor and roof's deflection. Most non-engineers have lost the art of balancing total systems combined deflection since each of these systems are engineered and produced by themselves. Truss floors, I-Joists, Trussed roofs and very little communication or coordination is done between these manufacturers, or their published load values by the builder/designers today.
Gotcha. So aside from stiffening the floor- which is an option. What do you guys think of completely disconnecting the walls from the floor? Install maybe rubber washers with screws that allow for vertical movement but no lateral movement? The floors in my opinion are stiff enough, but obviously the movement regardless of how small is causing a lot of noise within the walls. It’s VERY annoying. First time walking around the walls go SNAP SNAP POP. Btw I have tried removing the connection of the top plate and roof trusses in one room. They were nailed together via 2x4 blocking. The walls still made noise as it was moving with the floor.
I have very little experience with floor trusses, but I can't imagine properly sized ones deflecting so much that you hear and see nails popping!
A few years ago, I built an apartment over our detached garage. The joists had to span 22 feet, so I hired a structural engineer. He specified 16 inch I-joists on 12 inch centers.
I'm with Plumb 13. I'd get an engineer, or at least a building supply with a span chart to give you a real world idea of what size floor trusses should be there. If the ones you have fly I would find a way to connect them more securely to the bottom plate of the partition walls, which may have been intended partly to stiffen the whole structure (if they are located towards the center of the span). But you describe the nails throughout the wall making noise, so someone dropped the ball big time.
I would trust an engineer, and maybe a lawyer, on this one.