Chimney waterproofing in Keystone Heights by local experts

Visibly dry brick and a rain-free window

For a penetrating product to soak in, the pores need to have room for it. The maker's directions call for clean, structurally sound masonry that is visibly dry, and they rule out wet or saturated surfaces. They also ask for a six-hour window with no rain expected, unless the treated wall can be sheeted with plastic. After a run of wet days, brick can look dry at the face while still holding water further in, so on the day we check the brick itself, pressing and looking at freshly scraped mortar, rather than relying on the forecast and the look of the surface alone.

The splash test for when to reapply

You can check whether a chimney's treatment is still working without any tools beyond a spray bottle or a garden hose on a gentle setting. Wet a patch of each face. Brick that is still protected throws the water off in beads and keeps its dry color; brick that has lost its protection turns darker within seconds as it soaks the water up.

We run that test on every face, since the face that takes the most weather wears first. Only faces that absorb get another coat, which saves product and avoids stacking coats where they are not needed. The results, face by face, go into the job notes.

Water-based or solvent-based repellent

The active ingredient in a clear repellent is delivered in a carrier, either water or a solvent, that evaporates after the product has soaked in. BIA's note says the choice of carrier changes the conditions a product can go on in, and points out that green building programs set limits on solvent content. The two kinds also differ in odor, in clean-up and in how they behave on dense or damp surfaces. The product we name states its carrier, and we follow its limits on surface moisture, temperature and ventilation. The choice is explained if a solvent-based product is proposed.