How to Clean Polycarbonate Roofing

Why cleaning your polycarbonate pergola roof matters

Knowing how to clean polycarbonate pergola roofing properly will ensure the sun’s brightness shines through without any stains or debris spoiling the experience. It will also help keep your pergola looking new.

What you'll need to clean a polycarbonate roof — checklist of tools and supplies

Getting everything you need ready for your clean will make the task a lot easier. So here’s a list of items you’ll need:

• A sturdy ladder – to help you reach the roof safely without stretching.
• A broom or brush with soft bristles – to clear any debris from the roof and guttering.
• A garden hose with spray head attached – to give the roof a rinse before and after cleaning.
• A bucket of warm water – to mix with the cleaning fluid.
• Mild anti-static detergent – check the fluid is suitable for cleaning polycarbonate. Most liquids that clean acrylic and other types of plastic will be. 

2 x microfibre cloths – one for cleaning, the other for drying.

5 precleaning tips polycarbonate roof

1. Tip 1: Check the weather forecast – if wind and/or rain is due you’ve a good excuse to put off the clean for another day, as cleaning needs to happen in calm and dry conditions.
2. Tip 2: If you’re not comfortable cleaning while up a ladder, perhaps use a small scaffolding set-up or get a professional in to do the job.
3. Tip 3: Wear gloves to avoid any adverse reaction to the detergent you use, and non-slip shoes to ensure stability while you’re up the ladder. Safety goggles are also a good idea.
4. Tip 4:  A leaf blower is a good way to remove loose debris from the roof before you clean.
5. Tip 5: Avoid walking on your roof during cleaning. Yes, polycarbonate is over 250 times tougher than glass, but it’s designed for you to look through, not walk on. You should be able to reach all areas of the roof from your ladder.

Step-by-Step: how to clean polycarbonate roof

Step 1 – rinse the surface with water

After removing any loose dirt with a brush during the prep, start the clean by giving the roof a rinse with a garden hose. This will help soften dried-on stains.

Step 2 – use a soft cloth or sponge with soapy water

Wondering what to clean polycarbonate with? Use a microfibre cloth or sponge and submerge it in your bucket of water and begin the clean.

Step 3 – scrub gently without scratching the panels

Cleaning polycarbonate is a delicate process, so you can leave your elbow grease in your tool box. The best way to clean polycarbonate roofing is to scrub gently, starting from the middle of the roof and working outwards, so that any dirty water is washed away. 

It might take a little effort to remove dried-on stains such as bird droppings, but take care as polycarbonate is easily scratched.

You’ll likely need a couple of fresh buckets of water to ensure you’re not cleaning with dirty water, and be sure to rinse your cloth or sponge regularly.

Step 4 – rinse thoroughly to remove residue

When you’ve cleaned the roof, rinse any remaining soap and grime off the surface using a garden hose. Don’t leave any detergent on the polycarbonate as this will likely leave an unsightly streaky stain.

Step 5 – let it air dry or wipe with a soft cloth

Use your second microfibre cloth to dry the roof, or you can leave the sun to do the job for you.

Tips from the pros on keeping your polycarbonate pergola roof looking new

How often should you clean a polycarbonate roof?

A clean once or twice a year is usually enough to keep your pergola’s polycarbonate roof looking its best.

Obviously, try to remove any loose debris and wipe stains as and when you see them. But picking a mild spring or autumn day is best for a full clean, as it won’t be too hot or cold. Extreme temperatures may stop your detergent from working properly.

Dealing with tough spots or stains

Polycarbonate can scratch easily if you scrub too hard. So when faced with a tough stain, an area of grime, or the challenge of how to clear up cloudy polycarbonate, use a soft brush or apply a bit more force using your cloth or sponge. 

Wiping away spots or stains as soon as you see them on your roof is a good way to prevent them becoming dried-in and more difficult to remove.

Should you use a pressure washer?

No. A pressure washer is top of the list when it comes to what should you not use on polycarbonate. Never use a pressure washer when cleaning the polycarbonate roof of your pergola. The strength of the water could cause your roof to crack. Use a garden hose with spray attachment instead. 

Don’t forget to clean the inside of your roof

Although it won’t have been exposed to weather elements, the inside of your roof will still need an occasional clean to keep your polycarbonate roof looking as good as new.

The process of how to clean inside polycarbonate roof panels is much the same as for the outside. You can use the same detergent and follow the same tips and steps mentioned above to clean away spider webs and dust when needed.

What not to do — common mistakes when cleaning a polycarbonate pergola roof

Don’t pick a bad weather day for the clean
Not only will bad weather increase the likelihood of a slip on a ladder step, or more leaves and sticks blowing onto your roof. It will also reduce the effectiveness of your detergent, causing it to take longer to dry and potentially leaving stains on the surface.
Don’t use a detergent containing harsh chemicals
Always check the label of the cleaning fluid when you’re wondering what cleaner can be used on polycarbonate. It will say whether it’s suitable for polycarbonate. Using a detergent containing harsh chemicals will do more harm than good.
Leave the pressure washers for your decking
When it comes to deciding what to use to clean a polycarbonate roof, it might be tempting to speed up the rinsing stage by using a pressure washer. But you should avoid doing so. The power of the blast could crack your polycarbonate roof, spoiling your pergola.