7 Common Decking Problems and Solutions


Common garden decking questions answered

If your wooden decking is slippery, blackened, faded, dirty, warped or marred by unsightly gaps, all is not lost. Read on for expert advice about getting timber decking back into tip-top condition for a long, hot, lazy summer of alfresco fun.

Small garden deck in need of maintenance
Decked areas, no matter how big or small need care and maintenance to keep them in tip top condition

Slippery decking timber – How to make things safer

Our blog post about stopping slippery decking is one of the most popular ‘how to’ resources on our site. No surprise there when the great British weather delivers such a mish-mash of different conditions peppered with what seems like at least one record-breaking extreme weather event every year.

Here’s a link to How to Make Decking Non Slip. It tells you how and why decking gets slippery, and provides information about how to achieve non slip decking that’s both safe and good to look at.

garden decking
Garden Decking – Slippery when wet?

We also make product recommendations which are all backed-up by customers reviews from people who have purchased and used these products. Top of the list for anti-slip decking finishes are our range of anti-slip or slip resistant decking oils, closely followed by anti slip decking stains and coatings. Here are just a few of the top anti-slip decking treatments currently available…

Top 3 anti-slip decking treatments

Blackened decking – How to make your decking beautiful again

Whether you’ve gone for cheap decking or something sturdier and longer-lasting, blackening is a risk, especially after a long, wet winter. When fungus meets wet wood, the tannin in the timber reacts and forms a horrible black stain. It’s a sign you’re heading for rotten decking, something you really need to stop in its tracks before it damages the timber beyond repair.

We’ve talked about how to fix blackened timber decking in our blog post Wooden Decking Stains, Treatments & Oils: Part 2 – Problems & Cures. We also talk about dealing with wood rot in our post about How to Clean Decking, packed with practical advice about keeping your garden deck looking absolutely fabulous.

Both posts include sensible recommendations about fighting wood rot and getting rid of the black stuff, namely using  Barrettine Mould and Mildew Cleaner, a brilliant industrial-strength fungicidal wash designed to kill fungi, mould, mildew and algae. It also removes the famously nasty black slime and it’s perfect for use on exterior wooden doors, windows, garden sheds and fences as well as garden decks. Low odour and versatile, you can simply overcoat it with both wood preservation products and wood oils once fully dry.

Faded decking – Bring back that glorious natural colour and glow

A lot of people love the silvery sheen wood gets when it’s faded and worn. But the colour change actually signals UV and water damage to the surface of the timber and although it’s OK to leave it to fade, your decking will last longer if you treat the UV damage to help bring back the wood’s glorious natural colour and sheen. We talk about how to do this in the aforementioned blog posts.

Which products do we recommend for treating faded, silvery garden decking boards? There are now a range of decking restorers specially designed to restore your decking’s lovely natural look and colour. They do this with a compound called Oxalic acid that reverses the chemical damage done to the wood by sun and water.

The use and application can vary from product to product so always read and follow the manufacturers instructions on the tin. In essense you apply the product with a stiff brush or scotch bad scrubbing it into the surface of the wood, exercise patience for around twenty minutes then remove it with a hard-bristled brush and water. If the silvering is severe it’ll take some extra elbow grease and perhaps multiple applications. But it’s well worth the effort as the wood’s natural colour will come back through within 48 hours, just like magic. We recommend that once the colour has returned a clear wood preserver then a good exterior wood oil or decking oil is used to help protect the wood against further weather damage.

Top 3 decking restorers

Dirty decking – Get rid of the muck!

Our popular blog post about How to Clean Decking also delivers all the answers you need if your wooden garden deck is grubby and tired-looking. Luckily if all it’s suffering from is everyday dirt and muck, the solution is simple.

Dogs and Decking
Dogs and Decking

We recommend Barrettine Complete Decking and Patio Cleaner, a magical product that strips off dirt and grime like nobody’s business. It also helps control nasties like mould, algae and fungi and works on a host of different exterior surfaces, including concrete, stone and tiles. It’s easy to use, a nice quick job, and you can apply a good quality decking oil over the top, no problem at all. Ronseal Quick Drying Decking Oil is another firm favourite of ours – and our customers also love it.

Warped decking – How to fix bowed garden decks

If you’ve left your decking maintenance for too long you might find the boards have warped, something that happens when the deck hasn’t been adequately weather treated. It can also occur when the weather has been particularly bad. Whatever the reason, when your decking boards begin to warp and bow, you need to take action.

Here’s a video about straightening bent bowed deck boards…

And here’s some advice from Homeguides:

“Decking boards that have been in the sun and rain can’t help being affected, and some of them inevitably warp. This becomes a problem when a board pulls out the fasteners holding it to the joists.  Replacing the fasteners isn’t difficult – you simply pull out the old ones and drive new ones – but straightening the boards can be difficult. A solution is to use a bar clamp. Work one of the stops into the gap between two straight boards and place the other stop on the edge of the warped board, then tighten the clamp to draw the warped board into place. Use extra fasteners to hold it before removing the clamp.”

What if straightening the boards just isn’t going to fix the issue? You might have to replace the warped boards altogether, in which case here’s a link to some sensible advice about how to replace warped decking.

Gaps in decking – How to fill them?

If your deck’s full of nail holes or gaps where areas of rot have taken hold, how do you fill them? After all, wood flexes so you can’t use something that doesn’t flex with the substrate.

Luckily a good wood filling product, which acts like an epoxy filler, should do the trick. The instructions vary by manufacturer, but the basics are the same. Just bear in mind wood filler isn’t suitable for repairing gaps and holes so large they actually qualify as structural damage.

Here’s a video to help you repair gaps in decking…

More decking ideas – What if you want to add colour?

With 12 stunning shades to choose from, including slate, whitewash and stone grey, Ronseal Ultimate Protection Decking Stain  delivers rich, long lasting colour with excellent weather resistance, making it ideal for decked areas.

The product offers unrivalled durability with really good UV protection and it’s dry and rainproof in just an hour and a half. Better still it’s slip resistant, ideal for all kinds of decking designs whether it’s the smooth stuff or the version with a ridged profile, both softwood and hardwood decking.

Need our help with your decking project?

For more information about decking treatments and their uses, contact our team of resident experts who are always on hand to help with project advice and product recommendations. Alternatively, see our decking treatments FAQ page which covers many of the most commonly asked questions about decking treatments.

We love to see before, during and after photos of any wood finishing project. If you would like to share your decking project pictures with us, you can either send us some photos or share on our Facebook, Twitter, Pinterest or Instagram pages.

Other great decking related blogs

  • Garden Decking Stains, Treatments and Oils: Part 1- Getting Started
  • Wooden Decking Stains, Treatments and Oils: Part 2 – Problems and Cures
  • Decking Oils, Stains and Treatments: Part 3 – Application and Protection

    1. Hello:
      My deck painted wood deck with Sherwin Williams brown Deck paint has a black powder substance on it only on the part that has direct sunlight! Its also on my cedar pergola. Is this black mold?

    2. Hi. We put down new decking in June this year and was advised to put Barrettine Preserver on, which I did. I woke up this morning and some of the decking boards have turned black. Don’t know why this has happened. Our previous decking was down for 15yrs and this never happened (We used Ronseal decking oil on it) Just want to know how to fix it and what went wrong?

      • Hello Bronagh,

        Please could you send over some photos for us to take a look at and we can help with your problem. If you email us with the photos to wood@finishes.direct or via our contact us page, one of the team will be happy to take a look and see what the problem is and offer some advice on how to resolve it.

        Please include details of wood type, when and how much product was applied and anything else you feel may be relevant. Black on wood could be a range of thing from tannins staining, mould spores water damage, stains from fixings. If you get those photos over we can help/

        kind regards Samantha.

    3. I had my deck stripped of stain with power washer which “furred “ the wood. I’ve sanded to smooth so I could put clear coat to preserve . It will not smooth!! Decking is 13 years old. Any suggestion??

      • Good Afternoon Phyllis,

        Thank you for getting in touch with your question. Pressure washers are great for stripping away old treatments and ground in dirt. On wood however you do need to take care not to hold the nozzle too close to the surface of the wood, as this can splinter the wood. I can only really suggest further sanding to get that smoother result how far you can take this depends on the condition of the wood.

        If you are having continued problems then a very high build product such as the Ronseal Ultimate Protection Decking Paint may help with covering some flaws and giving the decking a year or two more use. It is a surface sealer and it is vital to ensure the wood is really dry before application of any sealer.

        Any breaks in the seal can be quickly patch repaired to prolong the life of the finish and in turn the wood. if you have any further question sat all please do not hesitate to get in touch vi our contact us page.

        Kind regards Samantha.

      • Hello Lee,

        Feel free to get in touch via our contact us page with details of the decking, wood type, finish, texture and any other relevant information, perhaps some photos and maybe I can help further.

        Kind regards Samantha.

    4. I have a lot of decking wood leftover and was thinking of using to replace shed doors which need replacing .my plan is to put a thin sheet of wood glued and maybe nailed at the back of the decks to protect from dampness or rain seeping through any gaps that might arise after I make the doors. Can you recommend what type of wood I could use. plywood might be a bit to heavy. Or would would it be best to use wood filler in-between the decks.

      • Good Afternoon Christy,

        Good to hear that nothing is going to waste. Here at Wood Finishes Direct we would always recommend reusing and repurposing where possible. I do think that for your project, marine ply is going to be the best option. Although not directly exposed to the element the door will be indirectly and will need to be a wood that can with stand the cold and damp. And the decking board will need something solid to be attached to. Weight may be an issue and it really depend on the size and framework of your shed. Do not take my word for it though as I am not an expert when it comes to structure and building, only the product and protection needed for the wood once built.

        If you need a filler for the long gaps or areas along the top and bottom then you could have a look at the Cuprinol All Purpose Filler it is ideal for long thin gaps and has some flexibility for natural movement in the wood.

        I hope that helps a some and if you need any further help and advice please feel free to get in touch via our contact us page.

        Kind regards Samantha.

    5. Advice please re decking: Our shed decking has narrow gaps running from front to back, which meant that during the torrential rain the rainwater ran all the way into our shed and flooded it. Can you seal or cover the decking on the outside front bit, about 6ft x 4ft?

      • Hi Gandha,

        I’m not sure that I fully understand the issue that you are experiencing. Could you contact us to explain further and perhaps supply some photos please. Once we have a better understanding of the problem we may be able to help.

        Thank you.

    6. Hi,

      I thought I stained deck bout 8 years ago with Butinox3 which I thought/ was told a stain, but it’s a paint!! I spent hours trying to sand it off, but to cut long story short, I ended up putting undercoat on whole thing and then bought Cuprinol garden shades, country cream, my problem is its washing off every time it rains????????
      Help if you can.

      Kind Regards,

      John McKinlay.

      • Hello John,

        Cuprinol Garden Shades are not considered suitable for use on decking as it is simply not durable enough for the general wear and tear that is expected with decking.

        My recommendation would be to go back to bare wood and apply a Preservative first to protect from mould, mildew and rot and then a Decking Oil such as Barrettine Decking Oil. This is water repellent finish that is easy to repair and maintain long term, no peeling or flaking and just requires a top up coat annually or bi annually.

        I hope that helps and if you have any questions please do not hesitate to get back in touch.

        Kind regards Sam.


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