Wood decking can quickly collect dirt, algae, and grime, especially in damp UK conditions. Over time, this can make the surface look dull, slippery, and harder to maintain.
The biggest mistake people make is using too much pressure or the wrong technique. Wood is a soft material, and aggressive cleaning can lift fibres, damage the surface, and lead to long-term issues like splintering or warping.
In this guide, we show you how to clean wood decking properly without causing damage.
If you want to avoid the risk of damaging the wood, a professional decking cleaning service is the safest option.
Our specialists use eco-friendly solutions and the right methods for each type of wood.
Quick Answer (Fast Method)
- Important:
Always start with the gentlest method high pressure can damage wood and shorten its lifespan.
Choose the Right Cleaning Method
Not all decking needs the same approach, using the wrong method can damage the surface or waste time.
Light dirt (dust, leaves, surface grime)
Use warm soapy water and a stiff brush. This is the safest and most effective option for regular cleaning.
Algae or mould (green, slippery surface)
Use a decking cleaner or oxygen bleach to break down organic growth and remove slippery buildup.
Heavy dirt or deep cleaning
Pressure washing can help, but only if done correctly. It should always be a last step, not the default.
How to Pressure Wash Wood Decking Safely
Pressure washing can be effective, but only when used correctly.
Wood is a soft material, and high pressure can lift the surface fibres, leaving it rough and more vulnerable to moisture. Over time, this can lead to splintering, warping, and faster deterioration.
Step 1: Prepare the deck
Remove all furniture, pots and obstacles. Sweep thoroughly, including between the boards where dirt and debris collect.
Step 2: Apply cleaning solution
Remove all furniture, pots and obstacles. Sweep thoroughly, including between the boards where dirt and debris collect.
Step 3: Scrub the deck
Scrub gently using a stiff brush. Always follow the direction of the wood grain to avoid scratching or damaging the surface. Focus more on visibly dirty or stained areas, there’s no need to over-scrub the entire deck.
Step 4: Rinse thoroughly
Rinse with a garden hose or very low pressure. Make sure all residue is removed, especially between the boards.
Step 5: Let it dry
Allow the decking to dry completely before using it. This helps prevent moisture buildup and reduces the risk of mould returning.
How to Clean Wood Decking (Step-by-Step)
Before you start, it’s important to follow the right order. Cleaning wood decking properly helps remove dirt without damaging the surface.
Safe PSI for Wood Decking
Getting the pressure right is the most important part of avoiding damage.
Start at the lowest setting and only increase slightly if needed.
Nozzle and Distance
The nozzle you use makes a big difference to how safe the cleaning is.
A narrow jet or getting too close concentrates pressure in one spot, which can cut into the wood or leave visible marks.
Correct Technique
Even with the right pressure, poor technique can still cause damage.
Holding the jet in one place or spraying against the grain can leave streaks, raise the fibres, or weaken the structure of the decking.
When to Consider Professional Decking Cleaning
If your decking is heavily soiled, slippery, or hasn’t been cleaned for a long time, a professional clean may be the safest option.
Working with the right pressure, equipment and cleaning solutions makes a big difference, especially for wood, where using the wrong method can cause permanent damage.
Our company (GB Cleaning) specialises in safe exterior cleaning, using controlled pressure equipment and surface-specific techniques to achieve effective results without damaging the material.
With over 10 years of hands-on experience and professional equipment, we tailor our cleaning methods based on the condition of the decking, ensuring effective and long-lasting results.
Common Mistakes to Avoid
A few simple mistakes can damage wood decking much faster than people expect.
- Using too much pressure: lifts the wood fibres and leaves the surface rough.
- Using a narrow nozzle: concentrates pressure and creates visible marks.
- Scrubbing against the grain: causes scratches and uneven finish.
- Holding the jet in one place: leaves streaks and weakens the wood.
- Holding the jet in one place: leaves streaks and weakens the wood.
When Should You Clean Wood Decking?
Regular cleaning helps prevent buildup and keeps the surface safe to use.
- Once a year is usually enough: removes dirt and algae after winter.
- Spring is ideal: clears moisture and debris buildup.
- Damp or shaded areas: may need more frequent cleaning.
- Dry weather: helps the wood dry properly after cleaning.
What to Do After Cleaning
Cleaning is only part of the process, protecting the wood makes the real difference.
- Let the decking dry fully: prevents moisture issues.
- Apply oil or sealer: protects against water and UV.
- Regular protection: helps reduce dirt buildup over time.
- Can I use washing-up liquid to clean decking?
Yes, it works well for light dirt and regular maintenance.
- Should I pressure wash wood decking?
Yes, but only on low pressure and with the correct technique to avoid damage.
- What PSI is safe for wood decking?
Typically between 500 and 1200 PSI, depending on the type of wood.
- How do you remove algae from decking?
Use a decking cleaner or oxygen bleach, scrub gently, and rinse thoroughly.
- PRO TIP:
If you’d rather avoid the risk of damage, getting a professional clean can save time and ensure the job is done safely the first time.
