Pressure washing is an effective way to clean your deck, removing built-up dirt, grime, mildew, and stains to restore its appearance. The key is to use the correct technique and settings to clean thoroughly without damaging the wood or composite surface.
Here's a guide on how to pressure wash a deck effectively:
Preparing Your Deck for Pressure Washing
Before you start pressure washing, proper preparation is crucial to ensure safety and achieve the best results.
- Clear the Deck: Remove all furniture, plants, grills, and any other items from the deck surface.
- Sweep Thoroughly: Use a broom to sweep away loose debris like leaves, dirt, and cobwebs.
- Protect Nearby Areas: Cover or move delicate plants, outdoor outlets, and other sensitive items that could be damaged by water pressure or cleaning solutions.
- Wet Surfaces: Lightly mist surrounding vegetation and painted surfaces with water beforehand. This helps dilute any cleaning solutions that might drift onto them.
- Choose Your Day: Pick a cloudy day or a time of day when the deck is not in direct sunlight. This prevents cleaning solutions from drying too quickly and leaving streaks.
Applying a Deck Cleaner (Optional)
For stubborn stains, mildew, or algae, you might consider applying a dedicated deck cleaning solution before pressure washing.
- Select a Cleaner: Choose a cleaner appropriate for your deck material (wood or composite) and the type of stain.
- Apply: Follow the product instructions for application, typically using a garden sprayer or a brush.
- Dwell Time: Allow the cleaner to sit for the recommended dwell time, but do not let it dry on the surface.
- Rinse: Some cleaners require a light rinse before pressure washing.
Pressure Washing Technique
This is where you use the pressure washer to lift the dirt and cleaner residue from the deck surface.
- Equipment: Use a pressure washer rated for approximately 1,500 pounds per square inch (PSI). Using a machine with significantly higher PSI on wood can easily cause damage.
- Nozzle Selection: Attach a nozzle that provides about a 30-degree angle spray pattern. Wider angles (like 40 degrees or white tips) are safer but less effective for heavy cleaning, while narrower angles (like 15 degrees or yellow tips, or 0 degrees/red tips) are too powerful and likely to damage the deck.
- Starting Point: Begin pressure washing in an inconspicuous area to test your technique and pressure settings.
- Maintain Distance: Position the nozzle at least 3 inches away from the surface of the deck. Keeping the nozzle too close concentrates the pressure, increasing the risk of damage.
- Consistent Strokes: Use smooth, overlapping strokes, moving in the direction of the deck boards. Avoid stopping in one spot, as this can etch or strip the surface.
- Overlap: Overlap your strokes slightly to ensure you cover the entire surface evenly and avoid leaving lines or "zebra stripes."
- Work in Sections: Tackle the deck in manageable sections.
| Setting | Recommendation | Reason |
|---|---|---|
| Pressure (PSI) | Approximately 1,500 PSI | Effective cleaning without excessive force |
| Nozzle Angle | Approximately 30 degrees | Good balance of coverage and cleaning power |
| Distance | At least 3 inches from surface | Prevents gouging or damaging the material |
Caution: As referenced, be careful. If you use too much pressure or get too close to the deck surface, you could damage the deck by splintering wood fibers, etching composite material, or removing finish. Always start with lower pressure, a wider angle, and a greater distance, adjusting as needed.
Rinsing the Deck
Once you have pressure washed the entire deck surface:
- Switch Nozzle: Switch to a wider-angle nozzle (like 40 degrees) or use a lower pressure setting (like the soap nozzle on some machines) for a final rinse.
- Rinse Thoroughly: Rinse the deck from the highest point downwards, ensuring all dirt, cleaning solution residue, and loosened debris are washed away.
- Check for Missed Spots: Inspect the deck for any missed areas or stubborn stains that may require a second pass or spot treatment.
Post-Cleaning Steps
Allow the deck to dry completely. This can take 24-48 hours depending on humidity and temperature. Once dry, you may consider sealing or staining the deck to protect it from future damage and enhance its appearance.
