Chimney cap replacement in Orange Park by local cap pros

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.

Round, oval and odd-size flue tiles

Flue tiles are made in square, rectangular, round and oval sections, and some chimneys carry sizes that no current cap catalog lists. A round tile takes a round slip-in or a band cap made for that diameter. An oval tile or an odd rectangle may need a cap built to measure, or an outside-mount cover sized to the crown instead of the tile.

We measure the tile at its top edge in two directions and check it for out-of-round before ordering, because a cap made to a nominal size will not seat against a distorted tile. A made-to-measure cap takes longer to arrive, and you hear the lead time before you approve it.

A damper that doubles as the rain cap

Fitted to the flue tile in place of a cap, a top-sealing damper has a hinged lid with a gasket and is opened and closed by a stainless cable that runs down to a bracket inside the firebox. Closed, it seals the flue at the top, which keeps conditioned air in the house and rain out of the flue. Models with a screen in the frame also keep animals out, as a cap would. It is chosen when the throat damper is rusted or warped, and it follows its maker's sizing just as a cap does. The one thing to remember is to open it fully before any fire is lit.