I want to remove a brick chimney down to the roof line because it's unused and also because it's a hazard from earthquakes in the SF bay area. This chimney came down in the 1989 quake but was rebuilt.

What will be the best way to seal this chimney from the elements if brought down close to the roof line? I'm thinking of building a sheet metal cap and gluing/screwing it on to the brick. I'm looking for the easiest and most efficient way to do this.

  • I'll pour a concrete cap. Depends on the size of the opening, you can place a rigid sheet metal plate as sacrificial form. Do not forget to add a few rebars in each direction.
    – r13
    Aug 20, 2021 at 1:31

1 Answer 1


Being sure to answer question: I would use Solar Seal caulk or, if I didn't have any, clear polyurethane caulk.

Your idea of installing a sheet metal cap will work, especially if it is bent downward and all the bolts are on the sides of the chimney, not the top. Don't forget to slightly bend the sheet metal upward with an X so that water will not sit on it.

You are better to remove the chimney below the roof, then fix the roof. This eliminates any flashing problems as well.

If the roof is not a problem now and the roof is somewhat old, you will probably want a cap and then finish removing the chimney the next time the roof is replaced.

If the roof is new or even slightly leaking at the flashing now, you will probably want to remove the chimney down into the attic and fix the roof.

  • 1
    All good suggestions. Make sure to use GALVANIZED sheet metal (or stainless steel, maybe copper if you are rich). Regular "duct" steel will deteriorate relatively fast in the SF air, even if painted. Alternatively, you could just brick over the opening, maybe with paver stones? Nothing needs to be functional hear, other than to keep water out.
    – JRaef
    Aug 20, 2021 at 0:30

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