Best way to lay deck boards on exposed trusses?

I get where you’re coming from, but I’ve actually had good luck with hidden fasteners - at least the newer ones. My deck’s pushing 8 years now and no rot yet, even with our crazy freeze-thaw cycles. Maybe it depends on the brand or how well you ventilate underneath? I do agree on not skimping with cheap screws though... learned that lesson the hard way on a fence project.

“Maybe it depends on the brand or how well you ventilate underneath?”

That’s probably a big factor. I’ve seen decks where poor airflow just traps moisture, and even the best fasteners won’t stop rot if the boards can’t dry out. On some jobs, we’ve had to go back and add more vents or even pull up a few boards to get things breathing better underneath.

Curious if you used any kind of membrane or tape over the trusses before laying the boards? I’ve heard some folks swear by flashing tape to keep water off the tops of joists, but others say it’s overkill unless you’re in a really wet spot. Around here (northern climate), that freeze-thaw can be brutal on anything exposed.

Also, what spacing did you use between your deck boards? I know some people go tight for looks, but I always worry about water getting trapped if there’s not enough gap - especially with hidden fasteners.

I’ve heard some folks swear by flashing tape to keep water off the tops of joists, but others say it’s overkill unless you’re in a really wet spot.

I used the flashing tape on my last build, mostly because I’d seen too many old decks with joists rotted right at the screw holes. Might be overkill, but it gave me peace of mind - plus, it wasn’t that expensive. As for spacing, I went with a fat 1/4" gap after getting burned once by boards swelling and buckling tight together. Learned that lesson the hard way after a rainy spring...

I hear you on the flashing tape. I skipped it on my first deck, figuring pressure-treated lumber would be fine, but after about 8 years those joists started looking pretty sad - especially where water sat under the boards. Ended up replacing a few way sooner than I’d hoped. On my second go-round, I used the tape and haven’t seen any of that early rot yet. As for spacing, I’ve gone as tight as 1/8" before and regretted it... boards swelled up and made a mess. Now I just use a couple of old nails as spacers - works out to about 1/4", give or take.

I get the logic behind flashing tape, but honestly, I skipped it on my last deck and just made sure to slope the joists a hair for drainage. Ten years in, no major rot yet - maybe I just got lucky with airflow under there? As for spacing, I’ve always stuck with 3/16" - seems like a sweet spot where debris doesn’t pile up but the boards don’t warp too much either.