- herr owen -
I have two flues in my chimney. They are unprotected at the top.
Swallow type birds will arrive with spring, and resume nesting in the
chimney.
At the top, the flues are almost flush with the mortar chimney cap. I
purchased a couple of screened "chimney caps" at the home repair, but
they need an inch or so of exposed flue in order to mount correctly.
Should I break the mortar, exposing more of the flue, and then
remortar?

- Nehmo -
If you are set on using those spark & bird guard covers, make a tube of
sheet metal (galvanized steel would do) about a foot long and shaped to
fit inside the flue. Position your tube inside the flue with an inch or
so is above the top of the chimney. Use sufficently long sheet metal
screws or bolts & nuts (you may be able to use the screws that came with
the cap) to attach the cap to the tube.

Actually, once you've determined the tube size you need, you can
assemble the arrangement while on the ground. Then go up and insert.

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* Nehmo Sergheyev *
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