sealing a threshold to concrete

[meackerman]

I build a shed on an existing concrete pad.   the pad had a bit of slope towards one of its corners.

Which means that to keep everything plumb and level I had to shim up one corner of the shed, which put the door threshold up off the ground on one side.  its plenty sturdy I can jump up and down on it and it doesn't flex or budge....I shimmed it with a bunch of plastic shims.  it works except water runs under the threshold into the shed.  I've got next to nothing on one end of the threshold and about 1/4" at the other end.

I tried sealing with PL Polyurethane concrete sealant, but I'm still getting water under the threshold.

I'm not going to tear it all down and start over, so since the concrete sealant doesn't seem to be completely stopping the water intrusion, I'm looking for another sealant....maybe roofing sealant?

[Stwood_]

I've always used caulking that had a high content of silicone.

[daddo]

On one of my outdoor sheds, the door opened to the outside, so I caulked it then made a metal flange to attach to the bottom of the door to deflect any blowing rain. If yours opens to the inside, then I think the roof sealant (Typically silicon) in a caulk tube would work fine.

Scrape out any old sealant, wire brush it, clean it with something like vinegar and let it completely dry first.

[K. L. McReynolds]

Non hardening external silicon sealer.

I always used two strips along the floor and up the sides.

[meackerman]

Non hardening external silicon sealer.

I always used two strips along the floor and up the sides.

along the floor....the threshold doesn't touch the floor because of the way the pad was poured.


So the best I can do is seal the front and the back of it.  maybe find some waterproof spray foam to spray under it and hope it doesn't expand too much and tweak the threshold.

[brianwelch]

Are you certain the water is only coming in from the threshold area? Could be that is where it is showing up, but necessarily where it's coming in...

[meackerman]

Are you certain the water is only coming in from the threshold area? Could be that is where it is showing up, but necessarily where it's coming in...

looking at the wetness on the inside of the shed, it starts at one side of the door and goes to the other, then follows the slope of the concrete.  there's no indication of any other water coming into the shed except at the threshold.

seems I'll strip off what's there, clean it up, and try some silicone.  Not a big fan of silicon...its a pain if you ever have to reapply it.

[dav]

I have a very similar issue with one of the doors on my shed. In my case, the builder didn't install a plate below the threshold. So, the threshold flexes and water can/does infiltrate. I've be thinking about sliding a piece of PVC trim under the threshold, machined to the appropriate thickness, then using a good exterior caulk to seal. I'm also interested in other ideas.

[daddo]

If you seal the threshold on the inside could it cause problems if there's a leak on the outside then water gets trapped in there without you knowing about it?

[CLETUS]

I tried sealing with PL Polyurethane concrete sealant, but I'm still getting water under the threshold.

Fix what is causing the water to flow toward the door.