I have a steel hatch to my basement that sometimes leaks under heavy rain. I've noticed that it's just one side of the hatch and if it's a sunny day I can see what looks like a few pinholes that the sun shines through.

I suppose I can try to re-caulk the perimeter of the hatch, but I was wondering if I can just apply a layer of flex tape since it's hard for me to see the holes from the top side and I do a pretty messy looking job with a caulk gun.

I've heard some say that flex tape is not UV stable and shouldn't be used outside but the advertising says it does. Can I use Flex Seal Liquid Rubber in a Can?

This doesn't have to last forever, as long as it helps with heavy downpours and can last 5 years. It's not in direct sunlight.

Is it ok to use flex tape, and if not, is there another product that is recommended?

  • 2
    Pin holes in steel usually not a good sign. Pin holes in weather stripping can be fixed or replaced. Picture or better location will help.
    – crip659
    Jan 15, 2022 at 13:37
  • I think it's in the weather stripping since I see it in the seam from below Jan 16, 2022 at 22:34
  • Weatherstripping is usually made to be replaced. Probably better to replace than trying to add to old stuff to keep. Flex tape or aluminum flakes would be better on the steel hatch/door itself if it is needed. Weatherstripping usually has too much give/movement to it(door squeezes it).
    – crip659
    Jan 16, 2022 at 23:06

1 Answer 1


It lacks the advertising budget of the products you mention, but aluminum flake roofing paint holds up well to UV (the overlapping aluminum flakes protect the rest of the paint layer) and works moderately well for a "long-term temporary patch" on flashing and roofing that needs to be replaced, eventually. So it would probably also work to seal pinholes in your rotting bulkhead that needs to be replaced eventually.

I suspect it may also cost less, due to not having the advertising expenses, but it does not come in a spray can as far as I know (so you might pay more for a gallon of it than for a 12 Ounce spray can of the other stuff.)

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