Composite Deck

How to Remove Mould from Your Deck

Australia received a lot of rain. This year, Queensland, New South Wales, and Victoria saw heavy rainfall, cyclones and flooding. Mould has spread throughout houses as a result of these excessively damp, humid conditions. With excessive rain and moist, your deck may develop mould.

You can work to avoid and eliminate mould. We’ll discuss what causes mould, how to prevent it, and how to recover your deck.

Deck rot caused by mould

Mould’s easy and rapid development is inconvenient. Mould thrives in moist environments and may grow almost anywhere. Mould develops in unexpected places during severe weather and storms because moisture is everywhere. This winter and spring have seen more wet conditions, so you should expect to see more mould.

Mould on all decks?

Mould may develop on almost any kind of decking, however particular materials are more prone to growing mould.

Mould grows on moisture-damaged wood. Spores may enter wood boards fast, making removal difficult. Mould may penetrate deep into wood, jeopardising its structural integrity. This may cause rotting and reduce the strength of your deck.

Mould does not grow on composite decking boards as much as the wooden decks.

Mould will remain a surface-level issue with regular cleaning and deck maintenance, preventing spores from reaching the core of your composite board.

Mould on composite boards is generally just on the surface. Mould-killing chemicals may be put to decking planks, but they’re dangerous to pets, children, and the environment, just to be aware of.

  • Black Mould

The majority of mould is black. Early stages of black mould might be dark green or a variety of other colours. If left unchecked, it has the potential to cause serious health concerns. Black mould is older and more difficult to remove from surfaces.

  • White Mould

Although not as widespread as black mould, it is nonetheless a concern. Mould loves wood and moisture. White spots or blotches are early warning indicators.

Mould inspection points

Look beyond the deck’s surface while looking for mildew or other concerns. A common mistake that may lead to a serious mould problem is failing to conduct a thorough assessment. Look under your deck and into every nook and cranny to avoid unpleasant surprises.

Detecting mould early, like with other problems, makes it easier to cure and saves further damage. Check your deck often. After a hard rain, keep an eye on your deck for a few weeks.

Mould elimination

Take caution while eradicating mould from your deck. You can always up the ante, but recovering damage is more difficult. If in doubt, get advice from the manufacturer or our composite decking specialists.

Pressure cleaning may be used to remove mould from a deck.

It is an art to operating a pressure cleaning effectively. Distance and hose pressure must be judged while pressure cleaning.

  • Make use of a fan tip to create a gentle, even flow. A thin tip is too concentrated and intense for decking but suitable for concrete.
  • When used incorrectly, pressure cleaning hose may be too much for the decking boards.

Hire a cleaning service

Professional deck cleaning may be worth it. With their experience and products, they will give you the peace of mind while also saving you time. Inquire with professional cleaners about deck mould removal.

Mistakes in mould removal

DO NOT USE BLECH TO REMOVE DECK MOULD. Because of the high PH, bleach is not powerful in killing mould and may discolour and destroy decking. Most likely, it will just bleach the mould, making it seem to be gone when it is still there.

What happens if mould grows?

Mould may lead to more serious issues:

  • It will become worse: Mould will continue to grow on the surface of your deck and deep inside the material if left untreated. Mould gets more difficult to remove as it develops.
  • Mould might pose a health risk to you and your family. Spores cause respiratory problems in both humans and pets. This affects small children, the elderly, and anyone suffering from asthma.

Checklist for Mound Prevention

Mould may be avoided with careful planning and design during construction. Mould prevention is easier than mould removal. Here are some things to think about while building your deck:

Ground Clearance

Always check below your deck for enough space between it and the ground. Mould thrives on moisture, and a deck that is too close to the ground may encourage dampness in the boards or framework. We recommend a dirt clearance of 20cm to 30cm to avoid damp from affecting the life of your deck.

Use a moisture barrier in water-stagnant locations. Your builder or landscaper may be able to advise you on this.


If water is the key to mould formation, proper deck drainage is essential. It is essential to have drainage that can resist water flow and heavy rain, as well as a slope beneath your deck to ensure water drains.

Mould avoidance

Keep dry.

Mould is caused by moisture. By draining as much water as possible, mould may be minimised.

Remove Debris

Leaves, twigs, and soil may absorb moisture and facilitate mould spores. Sweeping your deck on a regular basis helps to keep mould at bay.

Mould may grow on composite decking as well, although it is uncommon. It is a treatable problem that will not permanently harm your decks. Contact the crew at Superdeck if your decking boards are mouldy.