Curious if anyone’s had luck with sealing the underside of the boards before putting down underlayment? I’ve heard mixed things—some say it helps, others say it traps moisture.
I’ve run into this debate a lot. Honestly, I’ve seen both outcomes—one house I inspected had sealed undersides and it looked pristine after a few years, but another spot had some trapped moisture and started to cup. I think it really depends on your local climate and how much airflow you’ve got underneath. Swapping out questionable boards is definitely the safer bet, even if it stings the wallet a bit. Your “go by feel” method isn’t as unscientific as it sounds—sometimes experience just trumps gadgets.
Had a buddy who sealed the underside thinking he was a genius, but his crawlspace was basically a sauna. Meanwhile, my uncle’s place up north—no sealing, just good airflow, and it’s held up fine. Anyone ever tried those vapor-permeable sealers? Wonder if that’s the middle ground...
I get the appeal of sealing everything up, but honestly, I’ve seen more headaches than wins with that approach—especially in humid areas. Too much sealing and you’re just trapping moisture where you don’t want it. Good airflow’s underrated, but I wouldn’t go bare bones either. Those vapor-permeable sealers sound promising on paper, but I’m still a bit skeptical. If the deck can’t dry out when it needs to, you’re just asking for rot down the line. Sometimes old-school venting does the trick better than any fancy product... at least in my experience.
I hear you on the venting—my last deck turned into a science experiment after I went overboard with the “waterproof everything” mindset. Ended up with more mushrooms than a pizza. Now I just stick to basic sealers and make sure there’s airflow. Fancy stuff’s tempting, but my wallet says otherwise.
Ended up with more mushrooms than a pizza.
That line cracked me up. I went a little nuts with the “super-sealant” phase too—figured if one coat was good, three would be better. Turns out, not so much. The boards couldn’t breathe and I got this weird musty smell every time it rained. Airflow’s underrated, honestly. I still get tempted by those fancy products, but like you said, my budget usually brings me back to reality. Sometimes simple really is better... at least for my sanity.