Decking care
How to oil decking
Oiling decking every one to two years feeds the wood, restores its colour, and protects it against the wet UK climate. The key to a good result is starting with clean, dry boards and choosing the right weather window — ideally a dry spell of at least two to three days with temperatures above 10°C.
Video: Ronseal — UK wood treatment brand founded in 1956, widely available at Wickes, B&Q, and builders' merchants across East Kent.
Step-by-step guide
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Check the forecast and choose your window
Pick a dry spell with no rain forecast for at least 24 to 48 hours after you plan to apply the oil. Temperatures should be above 10°C for the oil to penetrate and cure properly. Avoid applying in full direct sun if possible — oil applied to hot boards dries too fast and can leave streaks. Early morning or overcast dry days work well in the UK climate.
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Clear and sweep the decking
Remove all furniture, plant pots, and anything stored on the deck. Sweep away loose dirt, leaves, and debris. Pay attention to the gaps between boards where leaf matter and grime build up over winter — use a flat-bladed tool or old knife to clear the gaps if needed.
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Clean the boards thoroughly
Use a decking cleaner or a diluted solution of timber cleaner mixed according to the product instructions. Apply with a stiff-bristled brush or a garden sprayer and scrub along the grain of the boards. Rinse off with clean water. For green algae or heavy weathering, a pressure washer on a low setting can be effective, but keep the lance moving to avoid marking the wood.
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Allow the boards to dry fully
After cleaning, allow at least 24 to 48 hours for the boards to dry out completely before applying oil. Decking oil will not penetrate wet timber and will sit on the surface, creating a patchy, sticky finish. The boards should feel dry to the touch and look their natural grey-brown colour rather than dark with moisture.
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Carry out a water absorption test
Sprinkle a few drops of water onto the boards. If the water is absorbed quickly and the wood darkens, the boards are ready to oil. If the water beads on the surface, the wood still has a coating or is too wet and the oil will not soak in. Wait longer or sand lightly with 80-grit abrasive paper to open the grain.
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Stir the oil and apply the first coat
Stir the decking oil thoroughly before use — pigments and protective compounds settle during storage. Apply generously along the grain using a wide decking brush or a long-handled applicator pad. Work one or two boards at a time, keeping a wet edge to avoid lap marks. Apply enough oil for the wood to feel damp rather than just skimmed.
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Work the oil into the gaps and edges
Use a smaller brush to work oil into the gaps between boards and around the edges and fixing screws. These areas are most exposed to moisture and most likely to be missed with a wide brush. Ensure the sides of the boards get coated as well as the top face.
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Apply a second coat if needed
If the first coat is fully absorbed within an hour or the boards look dry and patchy, apply a second coat before the first has fully cured — usually within two to four hours. On heavily weathered or porous decking a second coat is usually worthwhile. On well-maintained boards a single coat may be sufficient. Wipe off any excess that has not been absorbed after the final coat using a clean cloth.
Tips and common mistakes
- Never apply decking oil to wet boards — it will sit on the surface, go patchy, and peel off within a season.
- Clean before oiling every time — oil applied over dirt or algae will seal the contamination in rather than protecting the wood.
- The water bead test is the most reliable way to confirm the wood is ready to accept oil.
- Use a purpose-made decking oil rather than general wood oil — decking products are formulated to resist foot traffic and wet conditions.
- Stir thoroughly and keep stirring during use — pigment settles quickly and an unstirred tin gives uneven colour.
- Dispose of oily cloths and applicator pads safely — linseed-based oils can self-ignite if left bunched up. Lay them flat to dry outdoors or seal in a metal tin.
Would you rather have this done for you? Contact The Sandwich Handyman — decking cleaning and oiling is a straightforward garden maintenance job.