Chimney waterproofing in O'Neil by local experts

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.

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.

What the treated brick looks like

Once cured, a penetrating treatment is meant to leave the chimney looking much as it did before. The product's own literature describes little or no gloss and no change to natural color or texture, while noting that dense surfaces can darken slightly and that existing stains may become more visible. BIA adds that a noticeable sheen after treatment can mean the wrong product or poor application. The trial area is therefore judged dry, in daylight, from the ground as well as up close, and compared with untreated brick next to it before the rest of the stack is done.