How to Pressure Wash Outdoor Furniture the Right Way

After an Ontario winter, your outdoor furniture emerges from storage (or from under patio covers) coated in a winter's worth of grime, mould, and winter-salt residue. Before your first barbecue of the season, it all needs cleaning. But different furniture materials have very different tolerances for water pressure — knowing the difference saves you from a spring cleaning disaster.

Furniture Material Guide: Know What You Have

Before reaching for the pressure washer, identify what material your furniture is made from. This determines everything about how you should clean it.

Common outdoor furniture materials in Kitchener-Waterloo homes:

• Aluminum: Lightweight, rust-free, very common. May be powder-coated (painted) or bare metal. Handles pressure washing well.
• Resin/Plastic: The ubiquitous white or coloured plastic chairs and tables. Durable but can crack from very high pressure.
• Wrought iron: Heavy, decorative, traditional. Handles pressure well but must be dried immediately to prevent rust.
• Teak and hardwoods: Premium natural wood outdoor furniture. Requires lower pressure and grain-conscious technique.
• Cedar and softwoods: Lower-cost wooden furniture. Softest material in this list — very low pressure required.
• Wicker/rattan: Natural wicker (real wicker) is very fragile and should never be pressure washed. Synthetic wicker (resin wicker) handles moderate cleaning.
• Fabric and cushions: Never pressure wash cushion material — use low pressure or a garden hose only.
• Galvanized steel: Common in less expensive furniture. Handles pressure well but watch for rust at scratches.

Pressure Settings by Material

Technique Tips for Furniture Cleaning

Beyond pressure settings, technique makes a significant difference in furniture cleaning results:

Work on a patio or hard surface, not grass. The blowback from pressure washing furniture sends dirty water and debris in all directions. Working on a patio or driveway lets dirty water run off; working on grass just creates mud that re-coats the furniture.

Lay items on their side or stand them upright for different angles. Chair legs, table underframes, and decorative elements all harbour grime in crevices that won't clean if you only spray from one direction. Flip pieces to clean from multiple angles.

Use a cleaning solution for organic staining. Bird droppings, mould, and algae on furniture respond much better to a combination of cleaning solution and pressure than pressure alone. A dilute dish soap or all-purpose outdoor cleaner applied with a sponge or sprayer before pressure washing dramatically improves results. Let it dwell 5 minutes before washing off.

Rinse from the top down. Dirty water runs downward. Start at the top of each piece and work toward the base so dirty rinse water doesn't re-coat sections you've already cleaned.

Keep the nozzle moving. For furniture as for any surface, a stationary nozzle concentrates too much force on one point. Especially important for resin and wood furniture where concentrated pressure causes cracking or grain raising.

Clean glass tabletops separately. Glass patio table surfaces should be cleaned by hand with a glass cleaner and microfiber cloth rather than pressure washed. High-pressure water on glass patio tables can crack tempered glass, particularly if there are any pre-existing edge chips. This is an expensive lesson to learn.

Rust Prevention After Cleaning Metal Furniture

Metal furniture is particularly vulnerable in the critical period after pressure washing, when it's wet and any protective coatings that were damaged are exposed. Ontario's humid summer air can start rust formation on bare metal within hours.

Wrought iron: This is the most rust-vulnerable common furniture material. After pressure washing:

1. Immediately dry all surfaces with old towels — don't let it air dry.
2. Inspect for bare metal anywhere the paint or coating has chipped or worn.
3. Apply a rust-converting primer to any bare metal spots before the season's first use.
4. After drying, apply a coat of furniture wax (similar to car wax) over the painted surface to provide a moisture barrier. This also makes future cleaning easier.
5. Repaint any chipped areas with outdoor metal paint matched to the furniture colour before the end of the season.

Powder-coated aluminum: Much more rust-resistant than iron. However, inspect the powder coating for chips after cleaning — bare aluminum can oxidize and create a white powdery oxidation layer. Touch up chips with powder coat spray paint or outdoor metal paint.

Galvanized steel: The zinc coating on galvanized steel is your rust protection. Scratches through to bare steel will rust. Treat any scratches with cold galvanizing compound or zinc-rich primer before they rust. Once rust starts on galvanized steel, it spreads quickly to the surrounding zinc coating.

"The single most common mistake we see with wrought iron furniture is leaving it wet after cleaning. In Ontario's humid summer, rust can form within a day on exposed iron. Dry it immediately."

— David, D&D Home Services Co-Founder

Fabric and Cushions: What Never to Pressure Wash

Outdoor furniture cushions are the element most likely to be ruined by enthusiastic pressure washing. Even outdoor-rated upholstery fabrics (Sunbrella and similar) are not designed for pressure water application — the high-pressure stream drives water into the foam core and the seams, leading to:

• Foam cores that take days to fully dry even in summer sun
• Mould growth inside the foam that starts while the exterior looks clean and dry
• Seam separation where high-pressure water forces stitching apart
• Colour damage on some fabrics

The correct approach for cushions and fabric:

1. Remove cushion covers if they're designed to zip off (many outdoor cushions have removable covers).
2. Machine wash removable covers per the fabric's care label — most Sunbrella fabric is machine washable.
3. For non-removable cushions, mix a solution of mild dish soap in warm water.
4. Apply with a soft brush or sponge, working the solution into the fabric.
5. Rinse with a garden hose at normal pressure — just enough to flush the soap and lifted dirt out.
6. Stand cushions on edge in full sun to dry completely before storing them or returning them to furniture. Never store damp cushions — mould will grow in the foam within 24–48 hours.

For mould on cushions, a diluted bleach solution (1 part bleach to 10 parts water) applied and rinsed is effective for most outdoor fabrics, but test a hidden area first — some fabrics are bleach-sensitive. Sunbrella and most commercial outdoor fabrics are bleach-safe.

Storage for Ontario Winters: Protecting Your Investment

One of the most effective things you can do to reduce how much cleaning your furniture needs each spring is to store it properly over Ontario winters:

Indoor storage is ideal for cushions, smaller items, and any furniture that can reasonably fit in a garage or shed. Even a single Ontario winter outdoors ages outdoor furniture significantly.

For furniture that stays outdoors over winter:

• Use breathable covers rather than plastic tarps. Plastic traps condensation, creating a moist microenvironment where mould thrives. Breathable covers (sold specifically as patio furniture covers) allow moisture to escape while keeping snow and debris off.
• Apply furniture wax or teak oil (for wood pieces) before winter. This seals the surface and provides a protective barrier against moisture.
• Elevate off the patio surface if possible — even a few centimetres of clearance improves air circulation and prevents the furniture from sitting in standing water from snowmelt.
• Secure covers against wind — Ontario's winter storms will blow off any improperly secured cover, leaving your furniture exposed exactly when you don't want it to be.

Spring preparation: When you bring furniture out of winter storage or uncover it in spring, clean it before the first use. Winter storage — even indoors — allows some mould and mildew to develop, particularly on cushions stored in less-than-perfectly-dry conditions. The spring cleaning session removes this and prepares surfaces for the season.

While furniture cleaning is something homeowners typically handle DIY, if you're having us clean your deck, driveway, or home exterior, we're happy to include the patio furniture in our pressure washing service. It's much more efficient to clean everything in one visit.

D&D Home Services TeamExterior Cleaning Experts

D&D Home Services is Kitchener-Waterloo's trusted exterior cleaning company serving Kitchener, Waterloo, Cambridge, and Guelph.