Garden decking warning as Brits told avert 'serious damage' by looking for 5 signs

An expert has told Brits to check now for five signs that their garden decking could be set for serious damage during the winter. Dave Kile, owner and deck expert at Trex Protect, said: "Autumn is the perfect time to give your deck a check-up before frost and ice make inspections harder.

"A quick post-BBQ clean and a thorough pre-winter inspection can prevent thousands in repairs later. Think of it like an annual health check for your outdoor living space - small steps today keep it strong for years to come." He added: "Summer fun can take a bigger toll on your deck than most homeowners realise. Grease, spills, and moisture don't just stain the surface; they seep down and attack the structure. By the time winter weather sets in, those problems can quickly escalate." Mr Kile has advised as to what to do about dark stains, wobbly railings, soft spots, scratches and gouges and green and black patches.

Dark stains between boards

Q: I've noticed dark stains between the deck boards. What does that mean, and what should I do about it?

Mr Kile said: "Dark stains usually mean BBQ grease or liquid has seeped past the decking into the joists. Left untreated, it becomes a food source for mold and speeds up rot. The fix is simple: apply a degreasing cleaner, scrub between boards with a stiff brush, and rinse thoroughly. For older decks, you may even need to lift a board or two to clean hidden buildup."

Wobbly railings or loose boards

Q: My deck railings feel wobbly after a busy summer. What's going on?

The expert said: "That's usually just wear and tear from people leaning, sitting, or moving around during gatherings. The fasteners get stressed. The good news is, it's an easy fix: inspect the joints, tighten the screws, swap out any rusty brackets, and make sure you're using weather-resistant fasteners. That should restore the stability."

Soft spots underfoot

Q: I've noticed a soft spot when I walk across my deck. Should I be worried?

Mr Kile said: "Yes, soft spots are a red flag. They usually mean water or grease has gotten into the joists or beams underneath. Don't ignore it. Get underneath, check the framing, and if the wood is spongy, reinforce or replace it right away. Leaving it will only make the problem worse."

Scratches and gouges on the surface

Q: What about scratches and gouges on the surface? Are they just cosmetic?

The decking expert said: "Most of the time, yes, but they're worth fixing. Furniture being dragged or dropped can strip off the protective finish, which then lets moisture seep in. A light sanding works for small marks. For deeper ones, use a filler that matches your deck material, then reseal it so water doesn't get in."

Green or black patches along joists

Q: I've seen green or black patches around the joists. What does that mean?

Mr Kile said: "That's mold or mildew, and it feeds on trapped moisture. It spreads fast, so tackle it straight away. A scrub with a deck cleaner or diluted bleach solution usually does the job. Then look at airflow and drainage; mold comes back if the deck can't dry out properly."