I have a large masonry chimney that doesn't have a rain cap. The brick portion is about 2' x 4', and it has an 8" x 8" tile flue in the center. The flue is flush with the mortar chimney top, so there is nothing to clamp a standard chimney rain cap onto.

How can I attach a rain cap to the flat top of the chimney? I can't find any rain caps that don't clamp onto the sides of the flue.

  • Are you up for either adding a flue tile or mounting some steel to the chimney top?
    – isherwood
    Dec 5 '16 at 22:01
  • Mounting a flue tile would be pretty hard since there is nothing to mount it to. Can you run tapcons into the mortar chimney top or will it crack/leak?
    – user15741
    Dec 5 '16 at 22:07
  • I'd feel confident simply mortaring it in place, or you could use landscape adhesive (assuming heat tolerance).
    – isherwood
    Dec 5 '16 at 22:08
  • I'm assuming that the top edge of the top flue tile is exposed. Is that the case? Maybe add a photo.
    – isherwood
    Dec 5 '16 at 22:09

There are a couple of different ways, but you probably would need a custom cap made up:

1 - You can mount the cap to the brick from the side as in the first picture:

enter image description here

2 - You can mount the cap to the top of the chimney:

enter image description here

Pictures from: https://www.riversidesheetmetal.net/chimney-caps/

To mount from the side of the chimney, people normally use anchors, such as these or these. You need to drill the side of the cap or get it made pre drilled for this. You can also glue it down if you want, either mounted from the top (more common) or side.

A lot of people like to use something called liquid nails for that (top mount). If it was me I'd probably do both (depending on how much you actually pay for a cap, its not a bad idea) just to be sure, but if not, then I would anchor it from the side. Liquid nails is quicker, just make sure you get something appropriate.

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