I went foam first too, and honestly, it wasn't too bad. A couple things I noticed:
- Foam boards first made the membrane lay smoother for me—less wrinkles and bubbles.
- Used construction adhesive plus some tapcons in tricky spots to keep everything tight.
- Corners were definitely a pain though... had to trim foam carefully to avoid gaps.
Your membrane-first method makes sense too, but I think foam-first gives a cleaner install overall. Either way, sounds like you did alright if you only had minor dampness after those storms.
"Corners were definitely a pain though... had to trim foam carefully to avoid gaps."
Haha, corners are always the villain of DIY insulation projects. I swear mine looked like a preschool art project at first—had to redo them twice. Foam-first worked pretty well for me too, but honestly, either method can do the trick if you're patient enough (and have enough coffee). Glad you only got minor dampness after those storms... sounds like a win in my book.
Corners are definitely tricky—I feel your pain. One thing I've found helpful is cutting the foam slightly oversized first, then pressing it into place and marking exactly where to trim. Takes a bit longer, but it saves you from those annoying gaps later on. Also, if you're dealing with flood-prone areas, adding a bead of waterproof sealant along the edges afterward can really help keep moisture out... just an extra layer of protection that pays off in the long run.
Good tips there, especially the oversized foam trick. I've done something similar myself, though I tend to go just a hair oversized and then shave it down gradually. Learned the hard way after measuring perfectly (or so I thought) and still ending up with gaps—talk about frustrating.
One thing I'd add: waterproof sealant is great, but make sure you're using something flexible enough to handle slight shifts or settling in your walls. A buddy of mine went overboard with some super rigid industrial stuff once, and within a year, he had cracks forming along the edges. Not fun to redo.
Also, don't underestimate good drainage outside your home. Insulation and sealants are important, but keeping water away from your foundation in the first place makes a huge difference. I dug out a simple French drain last summer—nothing fancy, just gravel and perforated pipe—and it's been a game changer during heavy rains.
Corners will always be a pain though... seems like no matter how many times you do it, they're always awkward.
Good call on the flexible sealant—seen plenty of cracked rigid stuff myself. French drains are solid too, but curious if anyone's tried pairing them with gutter extensions or splash blocks? Seems like a simple combo could really boost effectiveness.
