Garden Decking Care: Cleaning, Treating and Repairing Timber Decks
How to clean, treat and repair timber decking, stop it getting slippery, and check the frame underneath before it becomes unsafe.
Timber decking looks great when it is new, but the UK climate is hard on it. Without care, boards go grey, slippery and eventually rotten. A yearly clean and treatment, with prompt repairs, keeps a deck safe and extends its life.
The quick answer
- Clean decking at least once a year to remove algae and dirt
- Treat or oil the timber once it is clean and dry
- Replace split, soft or rotten boards promptly
- Check the joists and posts underneath, not just the boards
- Keep gaps between boards clear so water drains
Why decking gets slippery
Algae and moss grow on damp, shaded timber, especially in autumn and winter. Grooved boards can trap dirt and water. Regular cleaning, good drainage and an anti-slip treatment or inserts reduce the risk.
How to clean decking
- Clear furniture, pots and debris
- Sweep thoroughly and clear the gaps between boards
- Apply a decking cleaner and scrub with a stiff brush
- Rinse with clean water. A pressure washer on a low setting can help, but too much pressure damages the timber surface
- Let it dry completely before treating
Treating and protecting
| Product | What it does | How often |
| Decking oil | Feeds the timber and repels water | Usually yearly |
| Decking stain | Adds colour and protection | Every one to three years |
| Anti-slip treatment | Adds grip to the surface | As directed |
| Preservative | Helps prevent rot in cut ends | When repairing or cutting |
Repairs
- Soft or split boards: replace them, and check the joist underneath
- Loose boards: refix with decking screws into sound timber
- Wobbly decks: check posts, joists and fixings for rot or movement
- Raised decks: check handrails and balustrades are secure
Frequently asked questions
When is the best time to treat decking?
On a dry spell in late spring or early autumn, when the timber is dry and rain is not forecast.
Is composite decking better?
It needs less maintenance and does not rot, but it costs more and can still need cleaning.
Can you repair or replace sections of decking?
Yes. Send photos of the damaged area and underneath if you can.
Related guides
Send photos and your postcode, or call 07444 262522.