I've seen the foam and Tyvek combo hold up decently in some interior projects I've worked on, but you're right—it's definitely not foolproof. If you're set on giving it a shot, maybe consider adding an extra moisture barrier or sealant layer to beef up the protection. Something like a liquid-applied membrane can add that extra peace of mind without blowing your budget completely. DIY is all about creative solutions, so keep exploring...you might just find the perfect combo for your setup.
I've had mixed results with foam and Tyvek myself. A few years back, I tried something similar on a small outbuilding—thought I'd covered all my bases, but moisture still found a way in eventually. Have you thought about looking into drainage solutions as well? Sometimes managing water flow around the structure can be just as important as sealing everything up tight. Just throwing another angle out there...
Totally agree about the drainage angle—it's easy to overlook how much water management impacts the overall foundation health. Did you happen to install any perimeter drains or French drains around your outbuilding? I've seen people skip that step thinking it's overkill, but honestly, managing runoff can make a huge difference. A buddy of mine had constant moisture issues until he finally bit the bullet and dug a simple gravel trench drain around his shed. Problem solved.
Also, curious if your soil type might've played a role here? Clay-heavy soils tend to hold water longer and can really complicate things when you're relying solely on sealing methods like foam or Tyvek. Did you check into that at all before starting your project?
You're spot on about clay soil—I learned that the hard way years back. Thought a solid vapor barrier and sealing would be enough, but nope... ended up retrofitting a French drain. Glad you caught it early, it'll save you headaches later.
Yeah, clay soil's tricky stuff. When I built my shed a couple years ago, I figured compacting gravel and laying down plastic would do the trick. Nope... first heavy rain and I had a mini-swamp on my hands. Ended up digging trenches and adding drainage tile—basically a mini French drain setup. Wish I'd known earlier how stubborn clay can be, would've saved me a weekend of muddy frustration.
