Our Services

Crown repair details that matter

Coating, edge repair or a new crown, and how our specialists decide between them.

A bond break around each flue

Clay or metal liners and the concrete around them expand and shrink by different amounts as they heat and cool. Lock the two together and the crown splits from the flue outward. It is why the state building code specifies a caulked break, per ASTM C1283, between the crown and every liner it surrounds.

On a crown we rebuild, each liner gets a separation and a flexible sealant joint so the two can move without damaging each other. On a crown we keep, we check the joint at each flue and reseal it when the old sealant has hardened or pulled away.

Enough flue liner above the crown

A liner that stands proud of the crown keeps water on the crown from spilling into the flue and gives a cap something to grip. Brick Industry Association guidance sets that projection at two inches or more above the finished crown.

Some crowns were poured up around the liner until it almost disappeared. When we rebuild a crown like that, we set the new surface to leave proper liner projection. If a liner is cracked at the top, we show you and price that repair separately.

Sealant at the flue joint

Around each flue liner, the crown is finished with a bead of flexible sealant in place of rigid mortar, and that bead wears out long before the concrete does. The Brick Industry Association recommends a good grade of polysulfide, butyl or silicone rubber sealant, installed with proper priming and backing, and advises against oil-based sealants.

A hardened, cracked or missing bead lets water run straight down the outside of the liner. Resealing that joint is a small job when the crown itself is sound, and we check it on every crown we look at.

White deposits on the upper brick

White, powdery staining near the top of a chimney is efflorescence. The Brick Industry Association explains that it forms when water carrying dissolved minerals reaches the surface of the masonry and evaporates, leaving the minerals behind. It is a sign of water traveling through the brick.

Washing the deposits off treats the symptom. We look above them for the source, which is often a cracked crown, an open joint at the flue or missing sealant, and we fix the water path before cleaning the face.