What's the best product to clean painted exterior siding in Calgary before winter?

TSP (Trisodium Phosphate) or a dedicated house wash detergent like Krud Kutter House Wash is your best bet for cleaning Calgary exterior siding before winter. These products cut through the accumulation of road salt, prairie dust, and chinook-blown debris that builds up on Calgary homes throughout the summer and fall.

Calgary's unique climate creates specific cleaning challenges that require the right approach. The combination of intense UV exposure, frequent dust storms from the prairies, and road salt spray from winter road treatments leaves a film on exterior paint that plain water simply cannot remove. This buildup not only looks unsightly but can actually degrade your paint film over time, especially on south and west-facing walls that take the brunt of Calgary's weather.

TSP concentrate (available at Home Depot and most Calgary paint stores for around $8-12 per box) remains the gold standard for heavy-duty exterior cleaning. Mix one cup per gallon of warm water and apply with a pump sprayer or soft-bristle brush. TSP cuts through chalky paint residue, salt deposits, and organic growth while being gentle enough not to damage quality latex paint. However, TSP requires careful handling — wear gloves and eye protection, and avoid getting it on plants or aluminum siding where it can cause discoloration.

For a more user-friendly option, Krud Kutter House Wash or Simple Green Pro HD offer excellent cleaning power without the handling concerns of TSP. These products are specifically formulated for painted surfaces and work well in Calgary's hard water. Expect to pay $15-25 per gallon concentrate at Sherwin-Williams or Benjamin Moore dealers. They're particularly effective on vinyl siding and won't harm landscaping when properly diluted.

Timing is critical in Calgary. Clean your siding on a calm day when temperatures are above 10°C — ideally in late September or early October before the first hard frost. Avoid cleaning during chinook conditions when rapid temperature changes can cause cleaning solutions to dry too quickly, leaving streaks. Work in sections, keeping the surface wet, and always rinse thoroughly with clean water.

The cleaning process itself matters as much as the product. Start from the bottom and work up to prevent streaking, then rinse from top to bottom. Use a soft-bristle brush for textured surfaces like stucco, but avoid pressure washing above 1,500 PSI on painted surfaces — Calgary's dry climate makes paint more brittle, and high pressure can drive water behind the paint film or strip paint entirely.

For stubborn stains common in Calgary — like rust streaks from metal fixtures or black streaks from asphalt shingles — you may need a specialized cleaner like Goof Off or Krud Kutter Rust Stain Remover. Test these products in an inconspicuous area first, as they can be aggressive on some paint formulations.

Consider hiring a professional house washing service if your home is more than one storey or if you have extensive stucco that requires specialized cleaning techniques. Professional services typically charge $200-500 for a full exterior wash and have the equipment to clean safely and effectively. You can find experienced house washing contractors through the Calgary Construction Network directory to compare local options and read reviews from other Calgary homeowners.

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Looking for experienced contractors? The Calgary Construction Network connects homeowners with qualified professionals:

• Onsite Contracting and Electrical Services
• The Original Workshop
• Mayken Hazmat Solutions LTD
• Turnbull masonry
• Earl's Paintworks