I'm trying to solve a water intrusion problem with a poorly installed roll-up door on my shed. Part of the plywood is exposed when the door is closed, so anytime it rains or snows the plywood gets wet. How can this be fixed?

Water also seems to be coming in from the gap between the concrete driveway and that white aluminum board (red arrow). I ripped up the plywood boards to look underneath and there was moisture under there. Can this gap be filled with Quikrete?

Every time it rains I have to go in there and dry the plywood so it doesn't rot, so I hope there is a solution I can DIY to stop water from getting in. Thanks in advance!

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  • It should be rebuilt so the door is closer to the outside/lands on the bottom frame. A cheap fix would be to get a large/wide rubber strip(large tire tube cut) screwed/bolted to the door and going past the white board.
    – crip659
    Feb 24 at 19:55
  • Is there a slope from inside to outside to ensure that water that gets in is encouraged (by gravity) to exit on its own?
    – FreeMan
    Feb 24 at 19:58
  • If so, some rubber flashing, covered by metal flashing (going from the seam of plywood out the door & covering the white board) will protect the wood and usher the water out. Won't stop it from getting in, though.
    – FreeMan
    Feb 24 at 20:10
  • Thank you. Yes there is a slope away from inside to outside, sloping away from the entrance of shed. Metal flashing sounds like a good idea. Would it be beneficial to seal the exposed plywood with exterior primer as an additional precaution? Maybe Kilz mold & mildew primer? Feb 24 at 20:48

1 Answer 1


I've installed similar doors in two yard sheds I've owned over the last 25 years. As has been suggested in comments, you don't need a water seal. You need proper drainage through a suitable threshold.

Shop around for an extra deep threshold with a peak in the middle or near one edge such that the slope is entirely outside the door. If you can't find something, ask a local metal working shop to bend you something. You may need to fit a wooden shim underneath to create slope if it's a simple sheet metal piece.

If for some reason you don't want to do that, put a drainage flange on the bottom of the door itself. It needs to have slope, so you will need some bumpers underneath to lift the door slightly from its present position.

The area near the channel is always troublesome. Consider extra water sealing on the plywood, and maybe even a drainage hole under the channel.

  • It's not clear if the channel is supported by the wall, or floor, but the bottom could be trimmed and a PVC wedge could be installed where the door hits the floor. If the wedge is sloped toward the outside, and the edges are caulked, it could help ensure that water drains outside. Basically, make sure every part where water could fall is sloped to "outside."
    – Huesmann
    Feb 25 at 17:24
  • Thank you @isherwood! For threshold, would I be looking into an aluminum door threshold type? Or would a rubber threshold made for garage doors also work? Feb 25 at 18:57
  • Anything that holds water. :) I deliberately left it vague because it's a matter of what's available in your community.
    – isherwood
    Feb 26 at 13:45

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