The Ultimate Guide to Composite Cladding Maintenance: Cleaning & Care

Part 1: Capped vs. Uncapped – What’s the Difference?

Just like our decking ranges, the level of care required depends on the type of board you have installed.

Uncapped Composite (First Generation)

Lack of Protective Cap Layer: Put simply, uncapped boards have an exposed wood-fibre surface texture, because of this, the board is slightly porous; if not cleaned, moisture will be retained in the board’s core, attracting the influx of algae and fungus or leading staining over time.

Frequency: We advise a general clean of your boards twice a year (Mostly during the Spring and Autumn months, when rain is most forecast). If your house is near any large trees or located in a damp area, be sure to keep an eye out for green algae spots or black mould on the surface to prevent build-up.

Capped Composite (Second Generation)

Capped Protective Layer: Capped boards have a thin, protective plastic shield (the “cap”) wrapped around them; this shield acts as a raincoat for your walls, drastically reducing moisture absorption and makes stains (like bird droppings) easy to wipe off.

Frequency: An annual clean (once a year) is usually sufficient to remove any general dust and cobwebs building on your board’s surface.

Part 2: Routine Cleaning (The High-Reach Method)

Unlike decking, you can’t just sweep cladding with a broom. You are working vertically, often at height; safety and the right tools are key.

Tools Required:

• Extendable Soft Bristle Brush – (Ideally one that connects to a hose/water feed) This allows you to reach the top of the wall without climbing ladders.
• Pressure Washer – This is optional but use with extreme care.
• Household Washing Up Liquid – (Or a dedicated composite cleaner).

The Method:

• The Rinse: Start by rinsing the wall down with a garden hose or pressure washer on a wide fan/low setting.

Note: Never blast the cladding close-up with a high-pressure nozzle. Doing so risks damaging the surface or forcing water up behind the boards (shiplap) where it shouldn’t go.

• The Wash: Mix warm water and washing up liquid (or cleaner) together in a suitable container.
• Low Reach: Use a bucket and soft hand brush.

Part 3: Stubborn Stains & Restoration

Sometimes, a quick wash isn’t enough – Here is how to handle specific issues:

Mould & Mildew (The DIY Solution)

If you spot small, black spots (mildew) or green algae on your boards, especially in shaded areas the below method should help you tackle them with ease:

• Method: Alternate applications of 5-8% acetic acid vinegar and baking soda as a paste mixed with water (or warm soapy water) to the area individually, rinsing after each scrub with a soft bristle brush.
• Top Tip: This works well for localized spots. For larger walls, use a dedicated composite cleaner (like Owatrol Compo-Clean) which is designed to lift grime without damaging the plastic cap.

Colour Restoration (Uncapped Only)

Has your uncapped cladding faded over the years?

The Fix: You can use a colour reviver (like Owatrol Compo-Care).

⚠️ Important: These products are primarily for Uncapped composite. Do NOT apply stains or revivers to Capped cladding without checking with us first. The non-porous cap may prevent the product from drying, leaving a sticky mess.

Part 4: ⚠️ What to AVOID (The Danger List)

Composite is resilient, but certain products will ruin the finish.

✖ leach: Never. Bleach will breakdown the wood fibres and prolonged exposure leads to damage of the plastic components in the board. This can strip the colour pigmentation right out of your cladding, leaving permanent white patches or streaks.

✖ Abrasive Scrubbers: Avoid wire wool, scouring pads, or “Magic Erasers.” These act like sandpaper and the abrasive grain will dull the textured finish of the board.

✖ High-Pressure Blasting: As mentioned, using a “dirt blaster” nozzle too close to the board can etch the plastic surface. Always keep the lance at least 30cm away and use a wide spray pattern.

Part 5: Winter & Storm Care

Your cladding protects your house from the worst weather, so check it after heavy storms.

• Check for Debris: After high winds, check that no branches or heavy debris have impacted the cladding.
• Airflow Check: When checking for storm debris, ensure nothing is blocking the vital ventilation gaps you left during the initial step-by-step fitting process. Whether it is snow drifts or piled-up Autumn leaves at the bottom of the wall, keeping this gap clear is vital. If it gets blocked, moisture can get trapped behind the system.

Final Thought

Composite cladding is an investment in the beauty of your home. A simple “wash and brush” once a year is a small price to pay to keep it looking brand new for decades.

Looking to upgrade to a low-maintenance exterior? Browse our collection of capped and uncapped cladding today.