Cleaning a wooden pergola helps protect it from moisture, sunlight, and everyday weathering. A gentle wash, safe stain removal, and a few seasonal checks keep it strong and beautiful. Regular care also prevents warping, mould, and fading.

Why Clean Your Wooden Pergola?

Cleaning your pergola keeps the timber healthy and helps it stand up to the British weather. Over time, sun, rain, and temperature shifts slowly wear down even the best wood. Dirt settles into the grain, moisture encourages mould, and UV rays dull the original colour.

Each timber behaves differently.

Cedar holds up well but still fades without care. Teak barely needs attention but still benefits from an occasional refresh. Pine needs more frequent help to stay protected. Pressure-treated timber resists rot, but it isn't immune to surface staining or algae.

Regular cleaning stops these issues before they develop. It’s also your chance to spot loose screws, small cracks, or places where water might be collecting. A bit of attention now saves you repairing larger problems later.

Getting Ready: Tools and Materials

You don’t need anything fancy to clean a pergola. Gentle tools that treat the wood with respect are all you need. A soft-bristled brush, warm soapy water, and a garden hose are enough for most jobs. This approach is kinder to the surface and stops unnecessary scratching.

If you’re tackling mildew or green patches, a mild diluted bleach solution is usually all you need. Gloves are helpful, and good ventilation is important if you’re using anything stronger than soap. What matters most is avoiding harsh scrubbers or anything high-pressure that could push water deep into the grain.

Step-by-Step Cleaning Process

A simple, steady routine keeps everything manageable.

Start with a good look at the structure. Loose fixings, discoloured patches, or heavy staining are worth noting before you begin. Move anything stored underneath so you have room to work, and gently pull back any plants growing over the beams.

Begin by giving the pergola a rinse with a hose. This alone lifts off dust, insects, and loose debris. Warm water mixed with mild soap is usually enough to loosen grime. Work with the grain as you brush, taking your time around joints where dirt likes to hide.

Washing the pergola

• Start by rinsing the entire structure with a garden hose to remove dust and loose debris.
• Mix warm water with mild soap.
• Scrub gently with a soft-bristled brush, always following the wood grain.
• Focus on corners and joints where grime gathers.

Sunny days are tempting, but choose one that’s mild or slightly overcast. Direct sun dries soap too quickly and stops it doing its job properly.

Dealing with Stains and Mildew

Stains and mildew often need a little extra persuasion, but gentle methods still work best. A diluted bleach solution helps lift darker marks or green growth. Let it sit for a short moment and then lightly brush the area until the stain releases.

For mildew or algae:

• Apply a diluted bleach solution (1 cup bleach to 1 gallon water).
• Leave it on the affected area for a few minutes.
• Scrub lightly with your soft brush.
• Rinse thoroughly to prevent residue.

Keeping Your Pergola Looking Great

Good maintenance doesn’t have to be complicated, just consistent. A protective treatment every so often keeps moisture out, slows colour changes, and helps the wood age gracefully. Whether you prefer a clear sealant, a natural-looking oil, or a coloured finish, each creates a shield against the weather.

Some woods like cedar or teak simply need a light re-oil from time to time. Pine or older pergolas might appreciate a stain or sealant every couple of years. Before applying anything, a light sand helps the new coat settle into the grain.

Small issues are worth catching early. A loose bolt, a splintered edge, or a small crack doesn’t take long to fix, but leaving them allows weather to work its way in. Seasonal checks make a big difference. A quick look for signs of moisture, rusted screws, or trapped debris helps the structure stay sound.

Climbing plants look beautiful but can hold moisture against the wood. A gentle trim keeps air flowing and protects the beams during wetter months.

With a little attention through the year, your pergola stays safe, steady, and a lovely part of your garden for a long time.

FAQ

What cleaning solutions are safe for treating mould and algae on wooden pergolas?

You can safely use diluted white vinegar or specialised wood cleaners designed for outdoor timber. Avoid harsh chemicals like bleach, as they can damage the wood and harm surrounding plants.

How often should I deep clean a wooden pergola versus just sweeping it?

A light sweep to remove leaves and debris every few weeks is fine, but a deep clean with soap and water is best done once or twice a year, especially after winter. This keeps the wood healthy and prevents buildup of mould or algae.

Should I use a pressure washer on a wooden pergola, or will it damage the wood?

You can use a pressure washer on a low setting, but keep the nozzle at least a foot away from the wood to avoid splintering or stripping the surface. For softwoods like pine, stick to hand washing with a soft brush.

How do I protect my pergola from water stains after cleaning it?

After cleaning, let the pergola dry completely before applying any sealant or wood oil. This helps prevent water stains and keeps the wood looking fresh.

Is there a best time of year to clean and treat a wooden pergola for lasting results?

Spring or early autumn are ideal, as the weather is mild and gives the wood time to dry properly. Avoid cleaning just before heavy rain or winter, as moisture can get trapped and cause problems.