You may desire a black cap for aesthetics, cost savings or both. As mentioned in a previous article, these caps get destroyed by oil furnace exhaust after a few years. In general, they tend to rust out after a while if not re-painted every 5 years or so. The cap in the photo above is a Gelco product and is constructed well, with heavy galvanized metal. A seven-year warranty is available. The standard sizes available are:

  • 8″ x 8″ (fits outside tile dimensions 6.25″ x 6.25″ to 8.5″ x 8.5″)
  • 8″ x 13″
    (fits outside tile dimensions 6.25″ x 11.5″ to 8.5″ x 13.5″)
  • 8″ x 17″
    (fits outside tile dimensions 6.25″ x 16.5″ to 8.5″ x 18.5″)
  • 13″ x 13″
    (fits outside tile dimensions 11.5″ x 11.5″ to 13.5″ x 13.5″)
  • 13″ x 17″
    (fits outside tile dimensions11″ x 16.5″ to 13.5″ x 18.5″)
  • 17″ x 17″
    (fits outside tile dimensions 11″ x 16.5″ to 13.5″ x 18.5″)

IMPORTANT NOTE: some of the older flue tiles were made of pumice and were square or rectangular. Then the tile manufacturing switched to terra cotta and began rounding the corners of the tiles. The 8″ x 12″ and 8″ x 16″ tiles actually became ovals.

Older, pumices tiles with square edges.
Terra cotta flue tile with rounded edges.
Terra cotta flue tile with rounded edges.

When

When it comes to the newer tiles with rounded corners, you want to order a cap that is closet to the actual outside dimensions of the tile. When I come across these newer tiles, I order A 12′ x 12″ cap for a newer tile that has rounded corners and outside dimensions of 12′ x 12″. The 13″ x 13″ listed above, even though its range of fit is appropriate, DOES NOT FIT WELL ON THE NEWER TILE.
I order A 12′ x 16″ cap for a newer tile that has rounded corners and outside dimensions of 12′ x 16″. Gelco does manufacture to these dimensions, but you may have to request them from the retailer by phone, as they may not have them listed on their website. The 8″ x 17″ Gelco black galvanized cap will fit the older and newer tiles well.

Rain cap mounted on a terra cotta flue tile with rounded corners.
Rain cap mounted on a terra cotta flue tile with rounded corners.

(c) 2019 Clifford Brand