Local chimney waterproofing in Riverside

Silanes on dense surfaces

Of the clear repellents, silanes have the smallest molecules. BIA's note explains that the small size helps them get into dense materials, and that they are supplied at high concentrations of active ingredient. The reaction that makes them water-repellent goes fastest on alkaline surfaces like concrete and concrete block, which act as their own catalyst.

On less alkaline clay brick, some products carry an added catalyst to help. Where a chimney has a very dense brick, a block section, or a concrete element that needs treatment, a silane or a blend led by silane may suit it better, and we explain the choice made.

How deep a penetrating repellent goes

The protection from a penetrating product sits beneath the face of the brick. BIA puts the depth at up to about 3/8 inch for penetrants in general, with no film left on the surface. The maker of the siloxane we use states penetration of up to 1/4 inch or more, varying with how porous the surface is and how much moisture it holds on the day. That depth is what lets the treatment outlast wear of the outer face. It is also why the brick has to be dry: pores already full of water leave less room for the product to travel, and the treated zone ends up shallower.

Applying from the bottom up

On a vertical face, the maker's directions for our product start at the bottom and work upward, using a low-pressure sprayer with a fan nozzle or a roller. Each pass floods the brick until a little excess runs down below the wet area, and a second wet application follows within minutes, before the first has soaked away. Starting low means any run-down falls onto brick that has not been treated yet, instead of streaking across finished work. Each face is completed in one continuous session so there are no lap marks where one day's work meets the next. Corners and the edges of the crown are cut in by brush where the spray cannot reach cleanly.