Good shout on the downspouts. Learned that lesson the hard way myself...nothing like walking into your storm shelter after a heavy rain and realizing you've accidentally built an indoor pool. 😅
One thing I'd throw in—make sure there's decent airflow in there. Had one shelter that passed inspections fine, but every time I opened it up it smelled like a damp basement. Ended up adding a small vent with a mesh screen to keep critters out, and it made a huge difference. Didn't take much work or money either.
Also, on the drainage angle (which is spot on), don't underestimate grading around the shelter. Had a place once where the shelter itself was done right, but the yard sloped slightly toward it and turned the area into a mini swamp after rain. A few hours with a shovel and some dirt fixed that up real quick.
Glad yours passed though, always good when things go smooth.
Definitely agree on the airflow point. I had a similar issue with mine—thought I'd done everything right until I opened it up after a humid week and got hit with that musty basement smell. Ended up installing two small screened vents on opposite sides for cross-ventilation. Took maybe an afternoon, cost next to nothing, and now it's way more comfortable down there. Worth the extra step for sure.
That's a smart fix—vents can make a huge difference. Reminds me of when we first moved into our place and discovered our storm shelter was basically a concrete sweatbox. I figured leaving the door cracked open occasionally would be enough, but nope...still had that damp, stale smell creeping in. Eventually, I rigged up a small solar-powered fan to one of the vents. Nothing fancy, just something cheap I found online. It runs quietly in the background, and since it's solar, it doesn't add anything to the electric bill (huge plus for me). Best part is, it completely solved the moisture issue.
One thing I'm still curious about though: has anyone here tried adding insulation or sealing around the door edges to help with temperature control? Our shelter tends to get pretty chilly in winter and uncomfortably warm in summer, even with ventilation. I've thought about weather stripping or foam insulation panels, but I'm hesitant to spend money on something that might not make much difference. If anyone's experimented with that, I'd love to hear how it worked out.
We tried weather stripping around ours last winter—cheap and easy enough. It helped a bit with drafts, but honestly didn't do much for overall temp control. Might try foam panels next...worth a shot if they're affordable.
We went with foam panels a couple years back, and honestly, they made a noticeable difference. Weather stripping is decent for sealing gaps, but foam panels add that extra insulation layer you might need. Installation was straightforward—just measure carefully and cut to fit snugly. One tip: don't skimp on thickness; thinner panels might save a few bucks initially, but thicker ones really help stabilize the temperature better in the long run.
Also, if you're worried about aesthetics (foam isn't exactly pretty), you can cover them with fabric or thin plywood. We used some leftover fabric from another project, and it turned out surprisingly nice...almost decorative. Anyway, definitely worth trying if drafts are still an issue. Good luck!