Trying to figure out the smartest way to lay down decking on top of some exposed trusses (not solid joists, but open web steel trusses in my case). I’m a bit stuck on whether I need to add some kind of sheathing or blocking first, or if there’s a way to just attach directly. My main concern is flex and squeaks, plus making sure it’s safe—don’t want to step through a gap and end up with a story for the ER, you know?
Also, do I need to worry about spacing for airflow or anything like that? It’s an outdoor setup, if that makes a difference. Anyone dealt with something similar, or have suggestions for what NOT to do? Would love to hear how others handled this, especially if you’ve got any “wish I’d known this” tips.
I’d definitely add some blocking or at least sleepers on top of those trusses—attaching deck boards straight to open web steel is asking for flex and squeaks, not to mention weird gaps. I learned the hard way that skipping this step makes everything feel bouncy. For airflow, just keep normal spacing between deck boards and you’ll be fine outdoors. Don’t try to bridge big gaps with decking alone... it won’t end well.
I get where you’re coming from, but I’ve actually seen some folks try to use composite decking right on steel trusses, thinking the material would be stiff enough. It really wasn’t—lots of bounce and weird noises, just like you said. Curious if anyone’s tried using rubber or foam strips between the sleepers and steel to cut down on vibration? I’ve wondered if that’d help with the squeaks or just make things worse over time...
- Seen a few jobs where folks tried foam strips between steel and wood—mixed results.
- Helps a bit with vibration, but over time, the foam can compress or even break down, especially if there’s moisture.
- Sometimes it actually made the squeaks worse as the foam aged and shifted.
- I usually go with treated wood sleepers, fastened tight to the steel, then deck boards on top.
- Anyone ever tried those rubber isolation pads they use under machinery? Wonder if that’d hold up better than foam in outdoor conditions...
Rubber pads under sleepers sound good in theory, but I’ve seen them trap water and speed up rot if you’re not careful with drainage. Steel trusses flex more than wood, so direct attachment usually leads to noise or loose boards over time. Blocking between truss chords helps a lot—just takes extra time. I’d skip foam, personally… never seen it last outdoors. If you go with sleepers, make sure they’re pressure-treated and spaced tight enough to support the decking—don’t trust the truss spacing alone. Learned that one the hard way on a rooftop deck job last year.