Garden Decking Care & Maintenance

Decked areas look great when new and well maintained, but what happens when the maintenance slips for a year or two? It doesn’t take long for decked areas to start looking tired, weathered and worn. Decking boards can turn grey due to water and UV damage, and mould and algae growth can make decking slippery and dangerous.

The good news is that all of these situations can be resolved with the right decking treatments. Decked areas can soon be restored, made safe, and enjoyed once again.


Common decking issues

3 of the most common decking issues that affect both softwood and hardwood decks include…

  • The loss of colour where decking boards have turned grey or silver over time, as a result of water and UV damage
  • Moss, mould, or algae, that has made wooden decking slippery and dangerous
  • Old decking finishes that have started to crack, peel or flake off

Which decking treatment do I need?

Deciding on which decking treatment to use depends on the type and condition of the deck. Is it treated or untreated? Are the boards softwood or hardwood? new or old? All of these factors can have an impact on the type of decking treatment that could and should be used.

Types of decking treatment

There are 5 main types of treatment for wooden decking, all of which can either protect, preserve, maintain, restore, and rejuvenate.


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


Decking maintenance – Where to start?

Before starting any decking maintenance or restoration project it’s important to understand what needs doing. The condition of the deck, 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, supple and protected from UV damage. 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 boards are bare wood or if they have been previously treated with an oil, stain or other treatment?

If the decking boards look dry, grey or silver, chances are that it’s probably untreated or that any previous treatment has worn away or peeled off over time.

If decking has a coloured finish, that is showing signs of cracking, peeling, or flaking, it has probably been treated with a coating type decking stain. These types of decking stains tend to form a plastic or varnish like coating over the surface of the deck. This said however, some brands of ‘decking stain’ are in fact coloured decking oils that penetrate into the wood and stain the wood from within.

If mould, algae or other signs of biological growth are present, it’s likely that the deck 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, Spring, Summer or early Autumn are best when day and night time temperatures remain above 10℃. If refinishing the deck with a decking paint or coating type decking stain, it’s important that the wood is completely dry. Idealy, the deck should have been exposed to dry and warm conditions for at least 3 or 4 days, day and night.

Before treating decking, always 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 or bleach may cause problems when trying to apply a decking treatment 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 decking stripper may be required.

Top 3 Recommended Pressure Washers

  • Bosch High Pressure Washer EasyAquatak 120: an efficient, robust, stable and space-saving pressure washer. Makes light work of a wide range of outdoor cleaning tasks. Concentrated power removing stubborn dirt  and the Fan Jet for rinsing and general cleaning.
  • Kärcher 16018850 K 3 Home Pressure Washer: Make light work of even the biggest cleaning tasks from gentle cleaning of delicate paintwork to removing stubborn dirt from a patio. This model includes a built in detergent tank for mess-free, easy detergent application.
  • Nilfisk C 125 bar Pressure Washer: ideal for garden, car, and household cleaning. Offers adjustable power levels, enough to efficient clean moderately dirty surfaces. Can gently clean soft or sensitive surfaces yet can also blast away ingrained dirt.

Once cleaned, especially with a power washer, decking timbers should be allowed to dry thoroughly for at least a couple of days in dry, warm conditions before applying any decking treatments. This time can vary depending on temperature and humidity.

Why maintain garden decking?

Well maintained decking will last much longer, especially softwood decking. Using a dedicated decking cleaner will effectively remove surface dirt, grease and biological growth whilst being safe to use on 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. Jet washing will remove the surface matter but will leave mould spores in the surface of the timbers. Left untreated and in the right conditions, mould spores will quickly regrow. 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.

Mould and Algae on wooden decking can be slippery and dangerous

Mould and Algae on wooden decking can be slippery and dangerous


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 fresh coat of oil. Oil-based decking treatments are available in a range of clear and coloured finishes. 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.

Where to buy decking

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

Softwood decking care

Before installing softwood decking, we recommend that all decking boards and posts are first treated with a 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, decking boards are ready for the main decking treatment, usually in the form of an oil, decking stain or decking paint.

As with decking preservers, it’s best to treat all sides of the boards and posts with 2 coats of oil, stain or paint before installation. This will again offer the best protection for decking 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, this can sometimes cause issues when applying an 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 will allow a hardwood decking oil to better penetrate into the surface of the decking boards than if applied when new.

Surface coatings such as some types of decking stain and decking paints may not adhere or bond well to the surface of hardwood decks if the wood still contains a high degree of natural oil. Some common brands of deck 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 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 wood cleaner or restorer can be used to prepare a bare wood or freshly stripped decking prior to applying a fresh decking treatment. 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 an 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 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 natural yet slightly ‘damp’ appearance. A way of testing how bare wood decking will look once a clear 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, white, green and blue are also available. Coloured products tend to provide better UV protection as the colour pigment in the oil helps to block UV rays. Find more information and our 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.

More Top Decking Treatments on Amazon

Garden Decking FAQ’s

Can’t find the answer to your garden decking care or maintenance project above? See our frequently asked wood decking questions and answers page, where we try to answer some of the more commonly asked questions relating to garden decking care, maintenance, and decking treatments.

Patio care and maintenance

So what happens if you have a patio instead of decking? Although patios don’t have to contend with wood rot, they should still be cleaned, maintained and sealed to keep them safe and protected. Patio areas are still vulnerable to mould, algae and lichen as well as general weathering. These things can make patios slippery and dangerous. To find out how to keep patio areas safe and maintained, see our patio care and maintenance guide.