What's the best way to clean painted garage walls in Calgary after a dusty winter?

Cleaning painted garage walls after a Calgary winter is best done with a simple two-stage process: a dry dust removal pass followed by a damp wash with mild detergent. Calgary's combination of road salt, fine prairie dust, and chinook-blown grit creates a particularly stubborn film on garage walls that needs the right approach to avoid damaging the paint surface underneath.

Getting Your Garage Walls Clean Without Damaging the Paint

Start with dry removal before you introduce any water. Calgary winters deposit a fine, alkaline dust — a mix of road sand, salt residue, and dried prairie soil — that scratches paint if you scrub it wet without removing the loose particles first. Use a soft-bristle brush or a dry microfibre mop to sweep walls from top to bottom, knocking loose dust, cobwebs, and debris to the floor before vacuuming or sweeping it up. Pay particular attention to the lower two feet of wall near the garage door, where road salt splash concentrates most heavily.

Once the dry pass is done, mix a solution of warm water and a small amount of dish soap or TSP substitute (trisodium phosphate substitute, available at Home Depot or any Calgary paint retailer). Avoid full-strength TSP on painted surfaces — it can dull or etch latex paint finishes. Work in sections from top to bottom using a soft sponge or microfibre cloth, rinsing frequently. For stubborn salt staining or exhaust residue near the garage door, a slightly stronger TSP substitute solution works well without stripping the paint. Rinse each section with clean water and allow it to dry fully before moving on.

For garage walls finished with latex paint — which is most common in Calgary residential garages — avoid abrasive scrubbers, magic eraser-type products on flat or matte finishes, and any solvent-based cleaners. These will dull the sheen and can actually remove pigment from lower-quality paints. If your garage walls have a semi-gloss or satin finish, you have more latitude — these sheens are specifically designed to be scrubbed and are the smarter choice for garage environments precisely because of annual cleaning needs.

One thing to watch for during your cleaning is paint that has started to chalk, peel, or bubble — particularly on exterior-facing walls. Calgary's extreme thermal cycling from chinooks stresses paint adhesion over time, and the freeze-thaw cycle through winter can accelerate peeling at any point where moisture got behind the paint film. If you notice sections where the paint wipes off on your cloth or feels powdery, that surface is failing and will need proper prep and repainting rather than just cleaning. Cleaning over chalky paint just removes more of the binder and makes the adhesion problem worse.

Mould or mildew spots — which can appear in Calgary garages despite the dry climate, usually near the garage door seal or on poorly insulated exterior walls — should be treated with a diluted bleach solution (one part bleach to three parts water) before the general wash. Allow it to sit for five minutes, then rinse thoroughly. Never paint over mould without treating it first; it will return through the new paint within a season.

After cleaning, this is actually an ideal time to assess whether your garage walls are due for a repaint. If the paint is more than 8-10 years old, chalking, or showing significant staining that cleaning won't resolve, a fresh coat of washable interior latex in satin or semi-gloss will make future annual cleanings much easier and protect the drywall or OSB substrate underneath from the moisture that comes with Calgary's spring melt season.

Most homeowners can handle garage wall cleaning as a straightforward DIY project. If you find significant paint failure, moisture damage behind the walls, or want to upgrade to a more durable finish, that's a good point to bring in a professional painter for an assessment.