Local chimney cap replacement for Ortega homes

Slip-in caps and the inside of the tile

A slip-in cap has a lower section that drops inside the flue tile and holds with screws or spring clips against the tile wall. It suits a tile with a clean, square top edge and inside dimensions that match a standard size. The fit is measured right at the top of the tile, where old mortar, chips or a rough cut can make the opening smaller than the tile's nominal size.

A slip-in section forced into a tight tile can crack it, and one that sits loose will rattle and walk. When the inside of the tile does not measure true in both directions, a band-mount or outside-mount cap is the better choice, and we explain which and why.

Anchoring a full-crown cap into sound concrete

An outside-mount cap covers the whole crown and fastens down through its own flange or legs into the crown or the top course of brick. The anchors are masonry anchors set into drilled holes, in a metal compatible with the cap so the fasteners do not corrode against it. Their hold depends entirely on what they are set into. Crown concrete that powders when drilled, or edges that are already cracked, will not keep an anchor tight through years of wind load. Testing the crown with the drill before committing to this cap type is part of our visit, and if the concrete fails that test, crown repair is written up as the first line and the cap second.

Copper caps and the fasteners they need

Copper and zinc-coated steel make a small battery when rain connects them, and the zinc and the steel lose. That is the reason a copper cap is fastened with copper or stainless hardware and kept clear of galvanized flashing or an old galvanized screen. Roofing metal suppliers publish the same rule for copper used anywhere on a roof.

When a copper cap replaces a galvanized one, every old screw and clip comes out of the crown. Any nearby galvanized part that has to stay, such as a flashing piece a roofer owns, is kept out of contact with the copper, and its position is noted.