Removing paint from brick in Medicine Hat and Redcliff

Painted brick is everywhere in this part of Alberta — garden walls, chimneys, the back of a commercial block, the lower course of a bungalow someone painted in the 1970s. Sooner or later the paint starts peeling and the question becomes whether it can come off.

Why painted brick peels

Brick is meant to breathe. Moisture moves in and out of it all year. Paint traps that moisture behind a film, and through our freeze-thaw winters it pushes the coating off from behind. Peeling paint on brick is usually a moisture story first and a paint story second.

Can it be blasted off?

Often, yes — wet and at low pressure, after a test patch. Masonry is always wet blasted. The water controls the dust and gives the control brick needs, and we stop the moment the face of the brick starts to change rather than when the last of the paint lets go.

Whether it works depends on the brick:

• Hard, modern brick usually strips well.
• Old, soft-fired brick may not tolerate even a gentle blast. The fired face is what keeps water out, and once it is gone it cannot be put back.
• Brick already spalling under the paint is telling you the face has failed in places. Blasting will not fix that.

The goal is to remove the paint, not the surface of the brick. If we cannot do one without the other, we will not start.

Medicine Hat and Redcliff are brick towns

With the I-XL works in Redcliff and the old clay industry in Medicine Hat, a lot of the brick on houses and buildings around here is local, and a fair amount of it is old. The older and softer it is, the more careful the conversation. Our note on blasting heritage brick explains where the line sits.

What to check before you call

• Roughly how old the building is.
• Whether faces are already flaking anywhere on the wall.
• Whether there is white powder bleeding through — that is efflorescence, and it points to moisture.