Sun, rain, frost, humidity, snow, sleet… we get it all in Britain, and every year our weather breaks yet another record: the wettest, hottest, driest, coldest.
As you can imagine all these temperature changes and different extremes can really knock the stuffing out of your decking, adding to the effects of everyday wear and tear. On the bright side there are some brilliant products out there for cleaning decking and preserving it, all specially designed to keep your deck looking its best and in tip-top condition.
We’re not going to tell you how to do decking. That isn’t our job. But we can tell you how to do the best possible job of decking maintenance. Here’s how to look after yours in the most effective way, for long-lasting life and beauty.
How to clean wooden decking
When to clean wooden decking? It might seem obvious, but you need a spell of dry weather if you want to prepare your decking for a (hopefully!) glorious spring, summer and autumn of gardening pleasure, leisure and alfresco fun.
How to clean garden decking?
Wooden decking is a wonderful feature, as practical and long-lasting as it is good-looking, but it can look very tatty if you leave it untreated and unloved. Thankfully even the ravages of the British weather can be overcome as long as you have the right products to hand. Better still, it’s a reasonably simple job. But first, what kind of problems might you have with your garden decking?
Common hardwood decking problems
- Blackened wood is common, caused by fungus growing on the surface of the wood. This usually happens when water gets in and reacts with the natural tannin in the wood. Different woods contain different amounts of tannin, so the problem varies in intensity. You can remove black fungus with a special fungicidal wash.
- Greying or silvering of the wood happens when it’s sun-damaged. Some people love the mellow effect but if you prefer your wood to retain its lovely colour, you can reverse the process using oxalic acid. There’s a brilliant product from Osmo called Wood Reviver gel, which contains the acid and can help to restore faded wood back to its natural colour.
How long do decking finishes last?
It can be a challenge to keep your decking in good order. Give it just a year and you’ll notice the effects of heavy foot traffic, spills and the elements, and see the surface deteriorating as the finish gets worn off a little at a time. This is why it can be so difficult for manufacturers to confirm how long a wood finish will last – there are so many variables. Then there are variations across a deck, where more direct sun in one area fades the wood more than in a sheltered area.
You may find you need more frequent decking treatment at the bottom of your decking’s spindles, where the wood can become extra dry, black or grey as the water runs down, taking the finish with it. This is where oils come in. Just rub the area with steel wool and treat it with more oil. Because oils deliver a seamless repair, they’re often a much better bet under these circumstances than finishes that seal the surface with a coating, much like a varnish.
What’s the best way to clean decking? The single most effective way to keep your garden decking in good condition is to sweep it regularly, keeping it free of anything that makes it damp or brings dirt to the party such as a build up of leaves and moss. If things are not too bad, a regular go with a good decking cleaner should do the trick.
Is your garden decking pre-treated?
Before you do anything, you need to establish whether your decking has been pre-treated. Most modern decking is treated with a wood preservative to protect against wood disease and insect attacks, but very few if any come fully finished, protected with an oil or decking stain.
Pre-treated decking is sometimes called ‘tanalised timber’, and you might also come across the term ‘tanalith’, the industrial name for a wood preservative. How do you know if your decking been pre-treated? Look for a green or brown tinge and check whether the surface colour is darker than the rest.
While clear wood preservers don’t contain pigments or dyes, the ingredients in them always influence the colour of the wood. As a general rule, if it has been pre-treated it’s ready for ‘finishing’.
Does decking treatment always involve a wood preservative?
If your decking is bare wood, with nothing on it at all, we highly recommend you use a wood preservative to lengthen its useful life and protect it against the elements.
If your decking was originally finished but needs a makeover, it’s important to get the right product for the job. You need to know what finish was used in the first place and use the same thing again. Luckily there are only two types, oils and sealers. Unluckily manufacturers don’t always use the same terminology, which means this’ll be helpful…!
Decking maintenance – Oils versus sealers
- About decking oils – Decking oils penetrate into the wood and become a part of it, with only a small amount remaining on the surface. The grain tends to show through beautifully and the wood retains its natural texture. An oil based decking product is advantageous because it’s easier to maintain and repair. Most people also prefer to see the natural wood grain rather than cover it up.
- About decking sealers - Decking sealers bond to produce a film on the surface, a lot like a varnish or paint. Because sealers sit on the surface the grain is slightly obscured, more like a semi translucent paint. It also feels smooth, without much texture. A sealer is more problematic because at some point it will start to peel and flake. It’s just a case of when. This means you have to remove the flaky stuff before you can re-coat your deck with something similar, which you must. If you don’t deal with the flaking, it peels and flakes even more.
Removing existing finishes from wooden decking
Once you’ve determined which finish is currently on your wood decking, you’ll either need to prepare the surface for re-finishing or remove it altogether. Which is right for your deck? It depends what colour you want and which finish you use.
- Sanding is only practical when your garden decking is smooth, with no grooves. If you have grooved decking, like most people, sanding won’t remove the finish from the grooves.
- Jet washing is a popular choice for removing flaky or peeling sealers. You can use a jet washer to clean decking finished with oils too, but you need to take care not to push the existing finish out of the wood and into surrounding plants, pond or soil.
- If you want to re-treat your decking with a sealer, you need to remove oil-based finishes with white spirit.
- If you want to re-treat a previously oiled decking with a fresh coat of oil, you don’t need to remove the lot first – just clean with a decking cleaner to remove any surface dirt, debris or other contaminates prior to re-oiling.
- A varnish stripper is ideal for removing decking sealer completely so you can replace it with an oil-based product
As a general rule, if you like the look and colour of decking oil, cleaning decking is your first step… then just re-apply 2-3 coats of fresh oil… easy!
Is my decking hard wood or soft wood?
Knowing the type of wood you’re dealing with helps you identify the ideal finish. Some exotic woods like Ipe and Bangkarai (also called Bangkirai) are very oily and sealers don’t work at all well. But don’t worry if you don’t know the actual wood type. It’s usually enough to know whether it’s made of hard or soft wood.
Making your garden decking water-repellent
Ideally, you want to make your softwood or hardwood decking water repellent. The idea is to get as much oil into the wood as possible, since hard woods are normally dense and oily. This means there are other things to consider.
Is the hard wood new or, more to the point, has it been cut down within the last few months? Most people will have no idea, but it’s important because the wood will be more oil rich when freshly cut than it will be 6, 12 or even 24 months later.
Some woods contain less oil than others and will allow 2 coats of oil, others remain oily for at least a year. Teak, for example, is widely used for external decks because of its high oil content, making it very weather resistant. It’s often best in this case to do nothing to untreated teak decking for the first year, then apply just one coat of decking oil a year later.
The best way of knowing whether a wood is ready for oiling or not is to drop small amounts of water on the surface.
- If it beads up and sits on the surface, the wood is oily.
- If the water sinks in and forms a blot or mark, the wood is ready for oiling.
- If the water sits there for 30 minutes or so before it begins to sink in, it already contains a reasonable amount of oil and will welcome one more thin coat of oil.
It’s worth bearing in mind that the colour of the wood before finishing will greatly influence the eventual colour. For example using a Cedar Red decking stain will give you three distinct colours depending on whether you apply it to new untreated pine, new treated pine or old untreated pine.
When do you need to start decking care and maintenance?
While you can find out when the wood is ready for oiling via the water drop test, it’s often easier to tell what’s what by its appearance. If the wood looks, dry, patchy, black or grey then it’s asking to be oiled.
Demystifying decking product manufacturers’ terminology
The wood finishing industry is full of inconsistencies. The terminology can be very confusing. Most people don’t know that a lacquer and a varnish are the same thing, and many of us confuse pigments with dyes. Here’s some guidance to help you get it right.
Decking stains – Tradesmen will probably tell you a stain is purely a colouring product, usually a liquid. It doesn’t give a sheen or protect the wood. Because it simply colours it, you need to add a protective finish. However a decking stain is rarely just a colouring liquid, it’s normally a colour with protective qualities. So far, so confusing. But things get even more complicated…
Ronseal are one of the leading suppliers of decking finishes in the UK and even they have two decking products, both called a stain although they’re very different. Their Ronseal Decking Stain falls into the sealer category, a paint-like material that doesn’t enhance the grain and will eventually peel and flake. But they also make an Advanced Decking Stain that’s oil based and far superior. In our opinion neither of these products should really be called a decking stain. And it’s a contradiction that isn’t unique to Ronseal.
How to differentiate them? Ronseal Decking Stain is best described as a coloured decking treatment while Ronseal Advanced Decking Stain is best described as a coloured decking oil.
Decking Oil - If it’s called a decking oil, it’s probably exactly that. In our experience it’s always a good choice when the product is made by a reputable company like Barrettine.
Decking Treatment – Beware! This could be an oil or a surface coating, and you need to find out which first.
Decking Finish – This could also be anything, so proceed with caution.
Best garden decking maintenance – The application bit
How do you apply decking oils and treatments to protect and keep your wooden decking looking good for years to come? The application techniques we’re going to talk about are relevant to oil-type decking finishes. There’s no need to discuss the sealer-type ones because we really don’t recommend them.
Note: This advice applies to decking that is either new wood, preserved new wood or wood that only has oil on it.
Once your garden decking is clean, you can apply a clear or coloured decking oil. Oils are easy to apply with no special skill required. It’s just a case of making sure the oil is pushed into the wood, not left on the surface. You can do it with a brush on textured decks, or with a long handled microfibre roller on smooth decks. If the decking is grooved you can attach a floor brush head to a wooden handle and use it to force the oil into the grooves.
How many coats of decking oil should I apply?
Try and get as much oil into the wood as possible. Because the oil content gives the wood protection against water, UV rays and more, it’s best to do a thorough and comprehensive job. You should apply the oil thinly since a thick coat can’t penetrate easily and takes ages to dry. It’s better and faster to apply three thin coats than two thick ones. Remove any excess oil with a lint free cloth.
As we mentioned earlier, oily woods sometimes don’t need further oiling for a while. Yours might only take one thin coat of oil before it won’t absorb any more.
It’s tempting to apply as much as you can in the hope that the more you apply, the better. But all you do is leave oily deposits on the surface which take ages to dry, sometimes more than two days. In the worst cases the oil won’t evaporate or sink into the wood because there’s so much oil it forms a skin on the surface of the wood, which could peel off.
There’s no need to use a lot of elbow grease. Just move the oil around on the wood and apply a little bit of pressure until it has virtually all sunk into the grain. A well-applied coat of oil will comfortably dry in a day.
8 top tips for beautiful wood decking
- Never use ‘sealer-type’ decking finishes. Use a top quality oil like Barrettine Decking Stain, also known as The Complete Decking Treatment. It contains resins and waxes, and we get excellent feedback about it.
- Always apply the oil thinly
- Get an idea of how much oil is still in your decking – do you really need to oil it yet?
- Clear coats of oil best enhance the grain structure for a lovely look
- The darker a finish, the more UV protection and the longer it takes to fade
- Sweep your decking regularly
- Put grooved decking face down – it’s much less slippery that way, and requires less oil because the surface area is smaller. Which means it’s easier to clean and finish. Apparently The UK is the only country where it’s the norm to expose the grooves – everyone else lays their garden decking smooth side up.
- Attend to any visible problems like greying, blackening and dryness quickly.
Colouring your decking
Black finishes on decking are becoming increasingly popular and provide a wonderfully dramatic contrast with the vivid green of plants and the bright colours of flowers. The easiest way to achieve this it is to use 2 coats of Ronseal black timber treatment, finished with 2 coats of clear decking oil. Alternatively, use a clear ‘Wood Preservative’ followed by 2 coats of Osmo black decking oil. Gorgeous.
Now you know how to clean decking. Yours has been properly prepared, treated and restored. Well done. Just add good company, food and drinks and… enjoy!
Handy wood decking maintenance links