Garden Decking Care & Maintenance

Decking treatment products – Which is best to maintain & care for decking

Decked areas can look amazing but if not maintained, can quickly fall into a state of disrepair, looking worn, tired and old.


Common decking issues

Common issues include the loss of the deckings natural colour, with the decking boards turning grey or silver over time. The build up of moss, mould or mildew that can make wooden decking slippery and dangerous. Or the unsightly appearance of old decking finishes that are cracking, peeling and flaking off.

Which decking treatment do I need?

Deciding which decking treatment to use can depend on the type and condition of the deck. Previously treated, untreated or old decking that has been left neglected will all require a different approach.

Types of decking treatment

There are 5 main types of garden decking treatment, all of which can be used to protect, preserve, maintain, restore and rejuvenate old and new, soft and hardwood decking. These are…


Grey, silver decking timber is a common problem that can be resolved.

Mould and Algae on wooden decking can be slippery and dangerous

Mould and Algae on wooden decking can be slippery and dangerous

The good news is that common decking problems can usually be rectified. With the right approach, decked areas can be restored in no time, to be enjoyed again and again, year after year.

Decking maintenance – Where to start?

Before starting a decking maintenance or restoration project it’s important to understand what needs doing. The condition of the decking, the desired look and the treatments required may vary. For example, a south facing deck that takes the full brunt of the summer sun may need a decking treatment that keeps the wood nourished and protected and contains UV filters. Wooden decking in a shaded location that is overshadowed by trees or bushes may require better protection from mould and algae due to falling leaves and damp conditions.

The first step is to determine if the decking is bare wood or if it has been treated with a decking oil, stain or other treatment?

If the decking boards look dry, grey or silver, chances are that it’s probably untreated or not been treated for a number of years.

If decking has a coloured finish, that is showing signs of cracking, peeling or flaking, it has probably been treated with a decking stain. Decking stains tend to form a plastic or varnish like film on the surface of the deck. This said however, some brands of ‘decking stain’ are in fact coloured decking oils that penetrate in to and stain the decking boards.

If mould, algae or other signs of biological growth are present, it’s probable that the decking is either untreated or that any old decking treatment has worn away or become ineffective.

Decking preparation

When planning to clean, restore or maintain a decking, it is best to do so in spring or summer, when day and night temperatures remain above 10℃ and dry conditions forecast for a couple of days.

Before treating decking, it’s always best to remove all traces of surface dirt, debris and other contaminates. Power washers are great for blasting off mould, algae and other biological matter. In the absence of a jet wash, a stiff broom and plenty of elbow grease is the next best thing. When cleaning decking, only use water or a dedicated decking cleaner. Using household detergent may cause problems when trying to apply a decking oil, stain or paint after cleaning.

Old decking finishes that have started to crack, flake and peel can usually be removed with a jet or power washer. failing this, a chemical stripper may be required.

Once cleaned, especially with a power washer, decking timbers should be allowed to dry thoroughly for at least a day before applying any treatments. This can depend on weather conditions such as temperature and humidity.

Why maintain garden decking?

Well maintained decking will look good and last much longer. There are a number of decking cleaners on the market that will effectively remove surface dirt, grease and debris and are safe to use on most decking finishes.

Slippery decking

When wooden decking becomes slippery, especially when damp or wet, it’s usually down to mould, mildew, algae or some other form of biological growth on the surface of the deck. Jet washing will remove the surface matter but will leave mould spores in the surface of the deck timbers. Left untreated and in the right conditions, these will likely grow back quickly. To kill off mould spores and remove any black and green staining from the wood, the use of a fungicidal wash or mould and mildew remover is recommended.

Grey, silver and untreated decking

Wooden decking that has turning grey or silver over time can be treated to restore the colour of the timber. Grey and silvering of exterior timbers is caused by UV ray and water damage. Decking restorers that contain Oxalic Acid help to reverse this chemical reaction, therefore returning the colour of the timber.

Previously oiled decking

Decking that has been previously oiled should be fairly straight forward to restore. Clean thoroughly with a suitable decking cleaner then apply a decking oil. Decking oils are available in a range of clear and coloured finishes. Decking oils with anti-slip properties are perfect for decking steps or decked areas at pubs and other commercial areas where safety is a key concern.

New Decking

When installing new wooden garden decking, there are several steps that will help to keep it in tip top condition for longer. It’s worth spending a little more time from the outset to reduce potential problems in the future, saving time and money.

When buying new decking, soft or hardwood, it’s worth shopping around for the best deals. Buying decking online can work out cheaper than from many of the usual retail chains. End of season sales towards the end of the summer months is also a great time to bag a bargain as stock is cleared.

Softwood decking care

Before installing softwood decking, we recommend that all decking boards and posts are first treated with a decking or wood preservative, all sides including the sawn ends. Wood preservers offer protection against the most common wood related problems including mould, algae and insect attack. Applying 2 coats to all sides and soaking all sawn ends in a quality wood preservative will help to protect decking timbers from these threats.

Once the wood preservative has fully dried, usually 24 to 48 hours for most, even though they may feel touch dry in 8 hours or less, the decking boards are ready for the main decking treatment, usually in the form of a decking oil, decking stain or decking paint.

As with the decking preserver, its best to treat all sides of the decking boards and posts with 2 coats of decking oil, stain or paint before installation. This will again offer the best protection for the decking boards and posts.

Hardwood decking care

Dense hardwood decking boards made from Ipe, Balau, Garapa and other exotic hardwoods are more resistant to wood rot and insect attack than softwood alternatives. This said, it doesn’t necessarily mean that they shouldn’t be treated.

Because dense exotic hardwoods used for decking can be naturally oily, it can sometimes cause issues when applying a decking oil. New hardwood decking often needs to be left untreated for a couple of months after installation. This is to allow some of the natural wood oil to disperse and for weathering to open up the tight surface grain. This allows decking treatments to better penetrate into the surface of the decking than if applied immediately.

Surface coatings such as surface decking stains and paints may not adhere or bond well to the surface of hardwood decks if the wood still contains a high degree of oil. Some common brands of decking oil may also be too thick or viscous to effectively penetrate in to the tight grain of the decking timber, especially when new. There are however highly refined decking oils that are extra thin that are perfect for the job such as Osmo Decking Oil.

Decking Cleaners and Restorers

Decking cleaners and restorers are used as both a preparation and maintenance aid. A decking cleaner or restorer can be used to prepare a bare wood or freshly stripped decking prior to applying a fresh decking oil, stain or paint. deck cleaning products are used to keep biological growth such as mould and algae under control and decking looking good for longer by preserving the finish.

Wood and Decking Preservatives

These speak for themselves. Wood preservers help to protect decking timbers from biological threats that would rot or degrade untreated wood. More information and decking preservative recommendations here.

Decking Oil

By far the preferred choice, decking oils are quick and easy to apply and provide a good level of protection and durability. The main benefit of a decking oil over a decking stain or paint is that they will never crack, flake or peel. This means that you’ll never be faced with the difficult and potentially time consuming task of trying to remove an old finish.

When high traffic patches of decking start to look worn or tired, it’s simply a case of cleaning the area to remove any surface dirt or debris. Then re-apply a small amount of decking oil to the affected areas. Even when the whole decking area, needs a re-fresh, simply clean then re-apply a fresh coat of oil to restore it to its former glory.

Clear decking oils tend to enhance the natural colour and grain of the timber and give decking boards a slightly ‘damp’ appearance. A way of testing how bare wood decking will look once a clear decking oil has been applied is to wipe a section of the deck with a damp sponge or cloth.

Coloured decking oils come in a variety of colours and shades. Although most people tend to go for a wood type colour such as Dark Oak, other colours like grey, black and white are available. Coloured products tend to provide better UV protection as the colour pigment in the oil helps to block UV rays. More information and decking oil recommendations here.

Decking Stain

Decking Stains generally provide a semi translucent, varnish like coating on the surface of the deck. This coating allows the grain of the timber to be seen while adding colour to the deck. Available in a wide range of colours, decking stains are tough, durable and seal the surface of the wood. More information and decking stain recommendations here.

Decking Paint

Decking paints produce a solid opaque finish and can be used as a ‘quick fix’ solution to improve the appearance of old decking. Available in a range of attractive colours, products such as Decking Rescue Paint can provide a modern alternative to traditional decking treatments. Other exterior garden paints such as Cuprinol Garden Shades are perfect for garden sheds, wooden fences, garden furniture and other garden wood but are not durable enough for decking boards.