Local chimney waterproofing for Hilliard homes

Protecting windows, skylights and shingles

Silane and siloxane products react with unprotected glass as well as brick, as BIA's note points out, and the note adds that these chemicals can etch glass. The maker of the product we apply adds paint, plants and asphalt-based materials such as roof shingles to the list of things to keep clear. So before any spraying, the glass in windows, skylights and doors close to the stack is covered, the roof surface around it is shielded, and plants below are protected as the directions describe. Any overspray that reaches an uncovered surface is washed off with soap and water straight away.

The crown takes a different product

The crown is the concrete or mortar slab across the top of the stack, and its job is harder than the brick's. Even a correctly sloped crown is close to level, so rain lingers on it and ponds wherever it has settled or cracked.

A penetrating repellent made for walls is not designed for that exposure. A sound crown with fine cracks is sealed instead with an elastomeric crown coating, which cures into a flexible membrane and comes with its own application limits. A crown with wide cracks or loose pieces needs repair or recasting. Either way it is priced apart from the brick treatment.

Cleaning the brick before treatment

A repellent has to reach the pores, and anything sitting on the surface blocks it. BIA's note is plain that the wall must be clean when the product goes on, since heavy dirt reduces penetration and shortens the life of the treatment. Chimney brick is cleaned gently: loose salt brushed off dry, dirt and growth scrubbed with a stiff fiber brush and water, and cleaning products used only where the brick maker's guidance allows them. Pressure washing at high settings can drive water deep into the brick and damage joints, and it adds days of drying before treatment can start.