Water – How to repair the caulking around basement walkout doors and what to use

basementcaulkingconcretewaterproofing

Another waterproofing question: our basement has a walkout door that is leaking from where the metal doors meet the concrete base. Three pictures from inside and one from outside are attached below. The metal doors extend beyond the small stop at the top of the stairs, so rain is draining (correctly) to the outside perimeter. However water is able to weep inside. There was old, probably latex-based caulk on both sides of the door stop, which apparently failed.

How do I repair this? Do I have to clean out the existing caulk and start fresh? Or is it possible to clean it and add a compatible latex-based caulk?

If I have to start from scratch, what should I use? I found several suggestions for caulking concrete (similar to this question plus hydraulic cement):

Walkout door inside 1
Walkout door 1
Walkout door inside 2
Walkout door 2
Walkout door inside 3
Walkout door 3
Walkout door outside 1
Walkout door 4
Walkout door outside 2
Walkout door 5
Walkout door outside 3
Walkout door 6

Best Answer

This does not look to me like something that can be fixed with caulking.

The entire door assembly is sloped away from the opening (good) but it seems as though water running down the doors is dripping off the end on to the concrete curb, then pooling and/or running back into the opening (bad). If it were me, I would:

  • use an angle grinder to smooth and further slope the curb edge away from the opening, just past where the doors "land" at the bottom.
  • wire brush, then prime and paint the entire bottom curb area, with a glossy polyurethane concrete paint. This will facilitate water runoff from the newly smoothed and sloped curb.
  • fasten a sheet metal strip to the bottom of the doors that is bent such that water running down the doors drips off beyond the top of the curb (a "drip edge", if you will...)
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