How to Remove Algae from Fence Panels

Have you noticed your wooden fence panels are gradually starting to turn green? These green stains are usually algae which can build up quickly. It’s important to remove any signs of algae from your fence as it can stain the wood and affect its look. It may also weaken the integrity of your fencing over time.

Join us as we take a look at why green algae grows on fences, how to remove it, and the steps you can take to keep your fencing algae-free.

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Algae can grow rapidly on fences due to the moisture and shade, which is facilitated by wooden fencing.
To remove green algae from a fence, you can use a pressure washer, a chemical spray-and-leave cleaner, or go for the natural option of hand scrubbing with vinegar and water. You should avoid painting over green algae on your fence; all algae must be removed before you apply any paint or stain.
To prevent algae from growing on your fence, apply wood treatments, try and reduce shade, and clean your fence regularly.

What causes algae build up?

Fences provide the perfect surface for algae to thrive. When it rains, or even just after you’ve watered plants near the fence, the porous wood creates a damp spot for algae to settle.

The algae will continue to grow in shaded areas where the sun can’t reach, stopping them from getting a chance to dry out. This is why the algae often appears on just one side of your fence.

The slats then let leaves and dust accumulate, which feed the algae the nutrients it needs to continue to grow. Essentially, fences provide everything algae needs to thrive. This is why you can’t simply paint over algae, and it must be properly removed first.

How can algae damage fence panels?

Since algae is primarily caused by trapped moisture within fence panels, it can lead to decay and rot in the wood if left untreated. Over time, this damage may cause the surface of the fence to splinter, weakening its structure and leaving it more susceptible to extreme weather and other hazards. Ultimately, green algae can accelerate the deterioration of your fence, meaning you may need to replace your fence panels sooner than expected.

How to remove green algae from a fence

There are 3 main ways to remove green algae from your fence.

The quickest and easiest way to remove algae without scrubbing is with a pressure washer. This is particularly good for stubborn algae that’s proving hard to remove. However, when pressure washing a fence, it’s important to use the correct settings and techniques to avoid damaging the wood. There are a few things you can do to mitigate this:

Use a nozzle that sprays the water over a wider area.
Keep the pressure washer at a low pressure.
Hold the nozzle no less than 2 feet away from the fence.

It’s best to always follow the grain of the wood and the direction of the panels when pressure washing, overlapping your cleaning pattern so you don’t miss anything or create water lines. After removing the algae, it’s important that you leave the fence to fully dry before applying any paints or treatments.

Often, fence cleaners and algae removers can be an effective way to rid your fence of any algae. Simply dilute the product using water and spray the solution directly onto the affected areas. You can then leave it to settle in and dry before rinsing off the product with water.

With minimal effort, you should be left with an algae-free fence. Make sure to check the product’s instructions, as different cleaners will require different product-to-water ratios. It’s also a good idea to wear goggles, gloves, and a mask when handling chemicals, and to put down a sheet to cover any nearby plants or grass that the chemical solution may harm.

For a more natural means of tackling algae without the use of a pressure washer, you can simply mix one-part white vinegar with two-parts water, and scrub this onto affected areas with a stiff brush. Then once you’ve scrubbed the whole fence, rinse off the cleaning solution with water and leave to dry.

Once you’ve removed the algae from your fence, you’ll want to make sure it doesn’t come back. When your fence is completely clean and dry, apply a wood treatment to protect it from the elements. This will repel water so that it can’t settle into the wood and, therefore, reduce the chances of algae growth.

As shade can also be a catalyst for algae growth, you may want to remove anything from the area that can block the sun from hitting the fence. This includes thinning shrubs and cutting back overhanging branches. It can also be beneficial to move potted plants to avoid any excess moisture from soaking into your fence after watering them.

Regular maintenance will also have a huge impact; whether that’s cleaning the fence and spot-cleaning algae growth or removing leaves and other debris from between the slats. To learn more about keeping your fence clean, check out our caring for your fence guide.

Even if you do regularly clean and maintain your fence, this doesn’t mean algae won’t come back. When it does, it’s important to remove it as soon as possible because letting it build up can result in damaged, rotten wood.

Whether you decide to use a pressure washer or scrub it away with chemicals or vinegar, it’s easy to get rid of algae growth once you’ve found it. And the difference it makes is huge, giving your fencing a clean, healthy appearance.

FAQs

You should avoid painting over green algae on your fence as this doesn’t remove the problem; it just covers it up. As algae can damage wood if left untreated, you’ll need to remove it before painting, ensuring a long-lasting, smooth finish.