Can I power wash a cedar fence safely or will it damage the wood grain?

Yes, you can pressure wash a cedar fence safely — but technique and pressure settings matter a lot. Done correctly, pressure washing is one of the best ways to clean a cedar fence in Metro Vancouver's wet climate, where moss, algae, mildew, and grey weathering build up quickly. Done wrong, it can raise the grain, splinter the surface, and leave the wood looking worse than before.

The key is keeping pressure below 1,500 PSI for cedar. Most homeowners reach for a standard electric pressure washer (1,200–1,800 PSI) which is fine as long as you use a 25-degree or 40-degree fan tip — never a zero-degree (red) tip, which concentrates the stream enough to cut into soft wood fibres. Hold the nozzle 12–18 inches from the surface and keep it moving in long, even strokes that follow the wood grain. Stopping in one spot, even briefly, can gouge the surface and leave visible lines that are difficult to sand out.

Spray angle matters as much as pressure. Always spray at a slight downward angle so water runs off the boards rather than being forced behind them or into end grain. Spraying upward under the boards traps moisture exactly where you don't want it — against the rails and post faces where rot starts. Work from top to bottom so dirty water runs down over already-cleaned sections rather than dripping onto clean wood.

Metro Vancouver Considerations

In Metro Vancouver's climate, cedar fences typically need a thorough cleaning every 1–2 years due to the combination of heavy rainfall, shade from neighbouring trees, and the region's naturally humid air. North-facing fence sections and any boards under tree canopy will develop green algae and black mildew significantly faster than south-facing sections. A diluted solution of oxygen bleach (sodium percarbonate) applied with a garden sprayer before pressure washing is highly effective at killing mildew and lifting green staining without damaging cedar fibres the way chlorine bleach can. Let it dwell for 10–15 minutes, then rinse with the pressure washer.

After washing, the wood grain will raise slightly — this is normal and actually beneficial if you're planning to stain or seal afterward. Let the fence dry completely before applying any finish. In Metro Vancouver, that means waiting for a dry stretch of at least 3–5 consecutive days, which realistically means scheduling this work between May and September. Applying stain to damp cedar is one of the most common mistakes homeowners make — the finish won't penetrate properly, will peel within a season, and you'll be doing the job again the following year.

Practical Tips

Once the fence is clean and dry, apply a penetrating cedar stain or sealer rather than a film-forming paint or solid stain. Penetrating finishes soak into the wood rather than sitting on top, which means they don't peel or blister when moisture gets behind them — and in Vancouver's climate, moisture always finds a way in. Semi-transparent stains in cedar-tone or natural finishes are the most popular choice because they enhance the wood's natural colour while providing UV and moisture protection. Plan to re-apply every 2–3 years to keep the wood protected.

Sealing cut ends is worth mentioning here too — any board ends exposed to rain (tops of pickets, bottom cuts near grade) should have end-cut preservative applied after cleaning. Cut ends absorb moisture far faster than face grain and are where rot typically starts first.

This is genuinely a good DIY project for most homeowners. You don't need professional help to clean and reseal a cedar fence — just the right equipment, the right pressure settings, and a dry weather window. If your fence hasn't been sealed in several years and the wood looks deeply grey or shows signs of surface checking (small cracks along the grain), a light sanding with 80-grit sandpaper after washing will open the wood up and help the stain penetrate much more effectively.