Best Way to Clean a Timber Deck

Aussie weather is glorious for time on the deck and also tough on our timbers. Be sure to address the wear and tear with a good cleaning and protect your deck for many summers to come.

Don’t neglect the bits of leaves and debris that build up, the mildew where you have a gutter leak or the tannin stains around your planters.  It’s time for a clean-up — for more than just aesthetic purposes — but where do you begin? Should pressure washing be part of your deck cleaning routine? How do you get a clean deck?

Regular Cleaning of a Timber Deck

Debris on your deck boards can cause moisture to get trapped, and water is not a friend of timber. Thus, a little regular clean-up of your outdoor space goes a long way.

Sweep your deck often. If you have pets that walk on your deck, keep their nails trimmed, as even pet nails can damage certain types of timber. High heels can also do damage to composite or timber decking.

The safest route for cleaning your deck is soap and clean water. For basic deck cleaning, you’ll need:

• A broom
• A garden hose
• A bristled scrub brush
• A biodegradable deck-cleaning solution (dish soap can work fine). Avoid bleach and acid solutions unless you’ve tested them on a small area not highly visible. Choose something eco-friendly and non-toxic.

Here is a simple step-by-step process:

1. Remove furniture and any other objects from the deck boards.
2. Sweep off any leaves or other debris from your deck. Work your way from the top down. Be sure to remove all cobwebs.
3. Test your cleaner on a small area to be sure there is no staining.
4. Clean with water, a cleaning solution and a scrub brush.
5. Scrub the entire deck. Don’t forget the railings and stairs.
6. Rinse off with a hose. Be sure to rinse thoroughly so it doesn’t leave a film.
7. Give the deck some drying time before moving furniture and décor back onto the deck.
8. While your deck is clean and clear, inspect it for any damage. Use this opportunity to make repairs. Replace any timbers that are dangerous.
9. If your timber is looking worse for wear, protect the surface by using a sealer or stain or oiling your deck. Cleaning first is essential, so you trap any debris in the stain or ​decking oil.
10. Move your furniture, grill and other accessories back in place. Be sure you’ve removed cobwebs and debris from these furnishings so you don’t dirty up the deck again!

Pressure Washing

Of course, sometimes it’s necessary to do a more rigorous cleaning. There are several deck cleaning products but beware of pressure washing.

Using a pressure washer may seem like a quick and easy way to clear out all the dirt and grime that’s been accumulating; however, you need to be aware of the damage it may cause. A power washer’s pressure may cause splintering and damage to the fibres of your timber deck.  If the surface already has some splintering, pressure washing will only exacerbate the issue.

You may have already heard about the problems of high pressure when washing a timber deck. But what about composite decking? Depending on the material, a power washer can also scar boards if the pressure is too high. If the power washing becomes too intense, it can even chip the material.

The biggest issue with power washing is the pressure. You may be able to use a low-pressure setting to aid in your cleaning; however, this may be a job for professionals.

If you DIY this project:

• First, ask for some instructions at the hardware store where you rent or purchase the washer.
• Give the timber some space. Hold the power washer at least two feet off the ground.
• Use a pressure washer with a fan tip attachment/adjustment and soap dispenser to remove soil, concrete dust, and other debris.
• Spray the deck with soap, then follow by gently scrubbing each deck board with a soft bristle brush.
• Rinse thoroughly. If dirty water from cleaning is left to dry, it will cause a film to remain on the decking surface.

If hiring a professional, be sure to ask for someone with deck experience and suggest using a relatively low-pressure setting (usually adjust the sprayer pressure to 1,500 PSI or lower).

Addressing Specific Cleaning Issues for a Timber Deck

Not every clean-up situation is the same. Try these tips for cleaning specific challenges.

Dirt and debris: Spray off the affected area with a hose to remove surface debris. Use warm, soapy water and a soft-bristle brush to remove soil and debris from the embossing pattern.

Tannin due to debris: Remove all debris from the deck using a hose or broom. Once the deck surface is dry, apply a “deck brightener” to the deck as directed by the manufacturer. Deck brighteners contain oxalic acid, which will remove tannins.

Oil and grease: Remove all food spills as soon as possible. To remove, spray off with a hose and use warm, soapy water and a soft-bristle brush to remove spills from the embossing pattern.

Mould and mildew: If debris, such as pollen and soil, is allowed to remain on the deck surface, mould can feed on the biofilm. Using a hose and warm, soapy water with a soft bristle brush is recommended to remove the food source and mould.

If your deck has reached the point of no return — it’s beyond stripping, sanding, re-staining and repairing — make plans for a new deck. To protect your deck in all Australian seasons, be sure to use a flashing tape such as Trex Protect. With its superior deck joist waterproofing power and deck cleaning skills, you can enjoy an outdoor living space for years to come!