Chimney cap replacement in Palm Valley by local cap pros

A flue tile cut level with the crown

Some crowns were poured up to the top of the flue tile, or the tile was cut off level with the concrete. Most single-flue caps need tile standing above the crown to clamp around or seat on, so a flush tile leaves them little to hold. The practical answers are an outside-mount cap that fastens to the crown itself, or a crown repair that re-forms the top with the tile standing proud and a caulked joint around it. We explain both, since the second also corrects a crown detail the chimney design note from BIA treats as standard: the tile standing at least 2 inches above the crown.

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.

Cap metal where salt reaches the roof

Salt carried on the wind settles on a cap and draws moisture to it, and chloride salt attacks metal that would last for years further inland. Some cap makers offer a Type 316 stainless line, sold as marine grade, for sites near salt water, since the molybdenum alloyed into 316 resists chloride pitting better than the common grade. A stainless-steel guide from the International Molybdenum Association adds that sheltered, rain-shadowed crevices hold salt longer than surfaces rain rinses, and a cap screen is full of such crevices. We follow the maker's grade guidance for the exposure, name the grade, and suggest rinsing the cap when the chimney is serviced.