I hear you on the mold—humidity here (Gulf Coast) is brutal, and tarps just don’t breathe. I tried doubling up with plastic sheeting once, but honestly, it trapped even more moisture. One thing that helped a bit was propping the tarp up off the roof with a few 2x4s to get some airflow underneath. Not perfect, but slowed down the funk. Still wish there was a magic cheap fix that didn’t bring a new headache...
I get the urge to double up on plastic, but honestly, every time I’ve tried that, it just made things worse. The moisture gets trapped and then you’re dealing with a whole new mess—mold, rot, you name it. I’m not convinced propping up the tarp is much better in the long run either. Maybe it slows things down a bit, but if you get a heavy rain or wind, those 2x4s can shift or even poke through the tarp.
What’s worked for me (at least for a few months) is using one of those woven blue tarps, stretched tight and secured with furring strips screwed right into the decking. Not pretty, but it keeps most of the water out and doesn’t seem to sweat as much as plastic sheeting. Still, nothing’s perfect in this humidity. I wish there was a cheap fix that didn’t end up costing more down the line... but I haven’t found it yet.
I’ve had similar luck with the blue tarps—definitely not pretty, but they seem to breathe a bit better than plastic. I tried using heavy-duty clear plastic once and it just turned into a greenhouse under there, which made the decking even worse. Have you ever tried any of those self-adhesive roof repair membranes? I’ve seen them at the hardware store, but I’m not sure if they’d hold up in our humidity or just peel right off after a few storms.
- Blue tarps do seem to let a bit of air through, but they're really just a stopgap. I usually see them start to break down after a few months in heavy sun or wind.
- Clear plastic is a mess in our climate—totally agree. Traps moisture, bakes the wood, and you end up with more rot than you started with.
- The self-adhesive membranes are interesting. I’ve inspected a few jobs where folks used them as a temporary patch. They stick well at first, but in high humidity, especially if the roof isn’t perfectly clean or dry, I’ve noticed the edges start to curl after a couple storms.
- If the decking is already damp, those membranes can actually seal in moisture and make things worse long-term.
- One thing I haven’t seen much is how they perform on different roof pitches. Steeper roofs seem to shed water better, but I wonder if the membrane would hold up better there compared to a low-slope section?
Has anyone tried using one of those membranes over older shingles versus bare decking? Curious if the surface makes a big difference in how long they last...
I’ve inspected a few jobs where folks used them as a temporary patch. They stick well at first, but in high humidity, especially if the roof isn’t perfectly clean or dry, I’ve noticed the edg...
I’ve tried the self-adhesive membrane over old shingles and bare decking. Over shingles, it stuck okay for a few weeks, but once the sun hit, the edges curled up faster than on bare wood. On bare decking, it held a bit longer, but if there was any moisture trapped underneath, I saw mold start within a month. The roof pitch definitely made a difference—on a steep section, water ran off and the patch lasted longer. Low-slope areas just pooled water and the membrane peeled sooner. Definitely not a long-term fix in my experience.