About deck cleaning & re-oiling
Deck cleaning and re-oiling is the routine visit: remove dirt, mould, tannin and surface grey, let the timber dry, then apply a maintenance coat of oil over a coating that is still basically sound. It suits decks that were restored or built in the last few years and have simply dulled. The cleaner matters as much as the oil. Oxygen-based cleaners lift grime and mould, oxalic acid brighteners remove tannin stains and grey, and both are scrubbed in and rinsed at low pressure. High-pressure blasting, the shortcut, tears the soft grain out of hardwood and leaves a furry surface that drinks oil unevenly.
Exposure sets the interval. A north- or west-facing deck above the surf at Bronte, Freshwater or Avalon Beach is hammered by UV and salt and can need oil twice a year. A shaded deck under tall gums in Pymble or Lane Cove may hold its colour longer but grows black mould and lichen in the damp, especially where leaf litter sits. Harbourside decks in Point Piper and Kirribilli fall between. One manufacturer's data sheet puts maintenance coats at every six to twelve months in extreme conditions. Jacaranda flowers, gum nuts and bird droppings left on fresh oil leave marks, so timing around the trees helps.
No licence is needed to clean and oil a deck, which makes vetting and environmental care the two things to look for. NSW pollution law treats detergents, cleaner residue and sediment entering the stormwater system as an offence, so rinse water should go to lawn and garden, not the street gutter, and a deck above a pool needs the pool covered or the filter watched. We check each tradie's ID against an active ABN, their public liability insurance and photos of recent decks in these suburbs, and each has signed up to quoting in writing and to the code of conduct before receiving a match.
What the job usually includes
How it works
- Tell us the jobSend photos of the deck in daylight, including any black mould, grey patches or tannin bleed, and tell us what oil was used last time if you know. Mention the aspect, whether a pool or garden beds sit below, and roughly how large it is.
- We match vetted local tradiesTradies in the network who clean and oil decks in your area receive the job. Each has shown us photo ID matched to an active ABN, a current public liability certificate, photos of recent decks and references. The matching service is free and you are not obliged to hire.
- They quote you directly in writingThe tradie quotes under their own ABN, naming the cleaner and oil, the number of coats and how many visits it will take, since cleaning and oiling usually happen on different days so the timber can dry. If they think the deck needs sanding instead, they should say so.
- The workFurniture is moved and surroundings protected, the deck is wet down, cleaner is applied and scrubbed with the grain, and the surface is rinsed at low pressure with run-off sent to the garden. After one or more dry days the tradie checks the timber is dry, applies a thin coat along the boards, wipes off excess so nothing pools and deals with the rags safely.
- After the jobKeep off the deck for the cure time the tradie gives you, move furniture back on pads, and note the product and date so the next coat matches. Then tell us how it went. Homeowner feedback after every match keeps the network's standard where it should be.
Low pressure, full drying and thin coats
The quality signals in this job are patience and restraint. A careful tradie tests the cleaner on a corner, scrubs with the grain and rinses with a fan tip at a pressure that would not hurt your hand, because hardwood grain lifted by a high-pressure lance never lies flat again. They match the chemistry to the stain rather than reaching for bleach, which greys timber and kills plants. Then they wait: oil applied to damp timber goes milky, sits on the surface and peels. Drying is confirmed with a moisture meter or at least a full day of sun, not a glance.
Application is where decks are ruined or saved. Oil should be brushed or padded along the length of the boards, a few boards at a time, with the excess wiped back before it goes tacky; puddled oil dries to a sticky skin that picks up grit and footprints. Products are kept consistent with what is already on the timber unless the deck is being stripped, because water-based and oil-based systems do not always sit well over one another. Finally, the environmental steps are not optional: wash water to the lawn, no run-off to the street drain, the pool protected, rags soaked or spread flat so they cannot self-heat.
Questions worth asking the tradie
Frequently asked questions
It depends on sun, salt and shade. Decks in full sun near the coast may need a maintenance coat twice a year, shaded decks less often. One oil maker's data sheet suggests a coat every six to twelve months where conditions are extreme. When water stops beading and the colour looks dry, it is due. Waiting until it is grey means a bigger job.
At low pressure with a wide fan tip, as a rinse after scrubbing, yes. Blasting at high pressure to remove grey or old coating tears the grain out of hardwood and leaves a rough surface that weathers faster. If a deck needs that much removed, it needs sanding, not more pressure.
Usually mould or lichen in shaded, damp areas, often where leaf litter sits or a pot plant has stood. Sometimes it is tannin reacting with iron from nails or steel furniture. An oxygen-based cleaner handles mould; an oxalic acid brightener handles tannin and rust marks. The tradie should identify which before scrubbing.
Only after the old coating has weathered or been stripped back, because the two systems do not always bond over each other. A maintenance coat should normally stay in the same family as the existing coating. If you want to change products, that is a restoration conversation, not a clean and re-oil.
To lawn or garden beds, not the street gutter. Letting detergents, cleaner residue or sediment reach stormwater is an offence in NSW (Protection of the Environment Operations Act 1997, often called the POEO Act). A careful tradie uses cleaners that are safe for plants once rinsed, covers the pool, and contains run-off.
No. Rags and pads soaked in decking oil can heat up and ignite as the oil cures. Manufacturers' safety data sheets say to soak used cloths in water or spread them flat to dry in a ventilated spot before disposal, never bunched in a bin. Ask the tradie how they handle theirs.
