How to Clean a Patio and Deck for Spring
Toronto winters are hard on outdoor surfaces — freeze-thaw cycles crack concrete, salt and sand embed into wood and composite decking, and green algae and mould develop on damp surfaces that don't dry quickly during the colder months. A proper spring clean extends the life of the surface and prevents slipping. Here's how to clean the most common outdoor surface types in Toronto backyards.
Wood Decks
Pressure-treated pine and cedar are the most common wood decking in Toronto homes.
- Clear and sweep — remove all furniture and sweep off leaves, dirt, and debris
- Check for damage — look for split boards, raised nails or screws, and soft spots indicating rot. Address structural issues before cleaning.
- Apply deck cleaner — use a commercial deck cleaner appropriate for wood (available at Home Depot or Home Hardware). Mix according to directions, apply with a brush or garden sprayer, let sit the recommended dwell time (usually 15 minutes).
- Scrub — use a stiff-bristled deck brush in the direction of the wood grain. This removes grey oxidation, algae, and dirt embedded in the wood fibers.
- Rinse thoroughly — rinse with a garden hose. If you use a pressure washer, use a low setting (600–1200 PSI) and keep the wand at least 12 inches from the surface — high pressure damages wood fibers and raises the grain.
- Allow to dry — wood decking needs 48–72 hours to dry completely before applying any sealant or stain. Applying sealant to wet wood traps moisture and causes peeling.
Composite Decking
Trex and other composite boards are increasingly common in Toronto and are easier to maintain than wood.
- Sweep and rinse with a garden hose — this handles most routine cleaning
- For stains and mould: dish soap and warm water with a soft brush. Scrub in the direction of the grain pattern, rinse thoroughly
- For stubborn stains: use the specific cleaner recommended by the decking manufacturer — Trex recommends their own cleaner for best results
- Never use bleach on composite — it discolours most brands permanently
- No need for sealant or stain — composite is sealed at the factory
Concrete Patio
- Sweep, then pre-wet the surface with a hose
- Apply a concrete degreaser or TSP substitute (trisodium phosphate alternative) for grease stains from the BBQ area — these are very common and require a degreaser to remove
- For general grime, algae, and mould: oxygen bleach (Sodium percarbonate — OxiClean works) mixed with water in a garden sprayer. Apply, dwell 15 minutes, scrub with a stiff brush, rinse thoroughly
- For pressure washing concrete: 2000–3000 PSI is appropriate — much higher pressure than for wood. Use a 25° or 40° fan nozzle, not a zero-degree pinpoint nozzle which etches concrete.
- Salt stains and efflorescence (white deposits): use a diluted muriatic acid solution (follow the instructions on the bottle carefully — this requires gloves and eye protection and neutralizing the surface afterward)
Outdoor surfaces are outside Maidless's standard cleaning services, but our deep cleans include every indoor surface. Book at maidless.ca.