How to weatherproof a pergola – 6 expert-approved solutions

Knowing how to weatherproof a pergola might not be high on your to-do list, but if you want to make the most of your outdoor space come rain or shine, it’s definitely worth prioritising.

The best pergola roof ideas don’t just look the part, they’re designed to withstand the elements too. And let’s face it, we see our fair share of wet weather in the UK, so waterproofing a pergola is a no-brainer if you want to enjoy it all year round.

One of the most important things to consider when building a pergola is how well it will stand up to the changing seasons. Just like weatherproofing garden furniture, it’ll ultimately save you time, hassle and repairs down the line.

Whether you own a sleek aluminium frame or a rustic timber structure, the good news is that there are different options when it comes to how to weatherproof a pergola. We’ve consulted the experts to understand the different options so you can get on with enjoying your pergola idea – whatever the weather!

The best ways to weatherproof a pergola

‘With the unpredictability of British weather, waterproofing a pergola is essential for enhancing its functionality,’ says Andrew White, outdoor expert at Harbour Lifestyle.

Over time, wet weather can wreak havoc on the structure of a pergola if it’s not weatherproofed, shortening its lifespan.

And waterproofing a pergola doesn’t just protect the structure itself, explains Sam Jenkinson, pergola expert at garden building retailer Tiger.

‘It also protects any furniture or flooring underneath. There are many effective ways to do this for all style preferences, and how much protection you may need.’

So, here are six expert-approved ways you can follow for how to weatherproof a pergola:

1. Install a louvred roof or waterproof canopy

‘Adding a proper roof is the most effective way to weatherproof a pergola,’ says Sam.

Louvred roofs are a popular choice – they’re made up of adjustable slats that can be opened to let in sunlight or closed to provide complete shelter from rain. Most modern louvred roofs are motorised too.

‘Sealing tightly when closed, the louvres ensure the rain is channelled through the built-in drainage system, keeping you dry and allowing you to make use of your pergola all-year-round,’ explains Reilly Gray, co-founder of Suns Lifestyle.

Alternatively, there are plenty of canopy ideas that can offer year-round shelter, such as a retractable canopy – ideally one that’s UV-resistant, waterproof or water-repellent.

‘A waterproof canopy or pergola cover offers instant protection from rain, snow and frost,’ says Martin Dooley, director of MD Carpentry Workshop.

For a more modern and low-maintenance solution, polycarbonate panels are an ideal choice, adds Sam. ‘These durable and lightweight clear or tinted sheets allow natural light through while blocking rain and UV rays.’

That said, it’s worth bearing in mind this option does require some upkeep, as Danielle Le Vaillant from Cox & Cox points out.

‘Adding a solid roof of polycarbonate to a wooden pergola will offer some shelter, but it does take away a little of the beautiful aesthetic of the wood and will also need regular cleaning and clearing of leaves and debris,’ she says.

2. Add side panels and blinds

To make your pergola even more weatherproof, it’s worth considering the addition of sides or screens as an extra layer of protection.

‘Retractable blinds, side panels, or even climbing pergola plants like wisteria can help block out wind and rain from the sides, making the space feel even more sheltered,’ says Sam. ‘They can also add privacy and make your pergola feel cosy, especially during colder or breezier months.’

We know when it comes to garden shade ideas, you can’t go wrong with a pergola – and adding blinds or panels only enhances their functionality, says Andrew from Harbour Lifestyle.

‘With blinds that retract up and down, or aluminium panels that tilt open and close, you can easily control how much light and sun you let in. Inset blinds function on a runner which make them highly resistant to windy conditions.’

3. Install gutters and drainage

Even if your pergola has a roof, you’ll need to make sure water doesn’t pool or cause any flooding or rotting underneath.

Many pergolas come equipped with a built-in drainage system, explains Andrew. ‘Rainwater is directed from the closed louvred roof into the pergola’s framework and then down through the legs to the ground. This design prevents water from dripping off the sides, keeping the area beneath dry.’

Martin, from MD Carpentry Workshop agrees that installing discreet gutters or downspouts will help divert rainwater away from the structure. ‘Regularly clear them of leaves and debris to prevent blockages and water build-up,’ he warns.

4. Add sliding doors

While you might typically think of pergola as an open structure, adding sliding doors – whether they’re slatted aluminium doors, glass, or made from acrylic – is one way to weatherproof a pergola.

‘Sliding doors can really enhance any aluminium pergola and create the ultimate outdoor sanctuary with improved insulation and more robust protection from heavier rainfall,’ says Andrew. ‘The sliding doors can also be opened to create a more seamless flow with your outdoor space.’

5. Use a protective sealant

Even with a roof, the timber of your pergola still needs proper protection from the elements – something you may be familiar with if you’ve ever prepared your shed for winter.

Applying a wood preserver, like this Barrettine Wood Preserver from B&Q, will protect it from moisture and temperature changes.

‘Wood is naturally porous, so without a protective barrier, it can absorb moisture over time, leading to rot, mould, or warping,’ explains Sam from Tiger.

‘Reapplying a wood preservative annually is essential, as coatings can wear down with exposure to sun and rain. An oil-based product will penetrate deeply and offer long-lasting defence, just make sure to apply it when the timber is clean and dry for the best results,’ he says.

6. Add heating

Once you know how to weatherproof a pergola, you’ll no doubt want to enjoy it all year round, and a great way to do this is by adding heat.

‘Whilst not a direct method of weatherproofing the structure, pergola heaters that attach to the inside of the frame allow a few extra hours in the garden once the sun goes down,’ Andrew says.

‘Combined with blinds pulled down or doors fully closed, the heater will keep your space warm without it being lost like it would in an open space.’

Just ensure the heater has an IPX5 rating, which means it’s certified to be outside and has a level of protection against low-pressure water.

Shop weatherproof pergolas

You’ll find that many modern, high-tech pergolas come equipped with louvred roofs, side panels and LED lights, and integrated drainage.

Tips for keeping a pergola weatherproof

• Brush off leaves and remove dirt and debris every few weeks to avoid trapped moisture.
• ‘Avoid using a pressure washer or scrubbing too hard, as these techniques can damage the wood,’ says Andrew, Harbour Lifestyle.
• Sam from Tiger recommends reapplying a wood preservative annually, as coatings can wear down with exposure to sun and rain.
• Inspect all metal fixings and replace any rusted screws or brackets with galvanised or stainless steel versions. This will protect against corrosion and keep your pergola secure through the seasons.

FAQS

Can you leave a pergola up in winter?

A well-constructed and properly weatherproofed pergola is designed to withstand winter weather. That said, you’ll need to make sure that any furniture or decorative elements that aren’t weather-resistant are stored away during the colder months.

A little seasonal prep can go a long way in keeping your structure looking its best year after year, recommends Martin, from MD Carpentry Workshop.

‘Start by giving your pergola a quick once-over. Check for any loose screws, cracked wood or general signs of wear and tear. It’s far easier to fix these issues before the temperatures drop,’ he advises.

During the colder months, you’ll need to keep on top of clearing away any snow as a heavy build-up can put pressure on the frame – avoid any long-term damage by gently brushing it away.

What is the best treatment for a pergola wood?

The experts recommend using a high-quality exterior wood preservative or sealant to protect against moisture, UV damage, and temperature changes.

Martin suggests looking for a product specifically designed for exterior timber that offers both water repellency and protection against mould, mildew and rot.

‘Clear sealants will maintain the natural look of the wood, while tinted or stained options can add colour and extra UV protection,’ he says.

For best results, apply a fresh coat once a year, ideally in spring or when the wood is dry, adds Sam. ‘This helps preserve the wood’s strength and appearance, keeping your pergola looking its best for longer.’

What is the life expectancy of a wooden pergola?

This really depends entirely on how well you look after the pergola, as well as the exact material it’s made from and the weather it’s exposed to.

With the right care and maintenance – including regular sealing and applying a protective wood stain once a year – a wooden pergola can last anywhere from 5-20 years.

‘Cheaper, untreated timber may show signs of wear within a few years, especially if exposed to constant moisture,’ says Sam.

Now you know how to weatherproof a pergola, whether you’re upgrading your existing set up or planning a new one, you’re well on your way to enjoying your outdoor space – whatever the forecast!