The Best Decking Sealer: Find Your Perfect Choice

There are so many ways to seal your decking and all have strengths and weaknesses. We explore which type is best suited to you.
Decking stain being applied
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Wooden decking needs to be sealed for it to last longer and look better.

Deck sealers come in different types, including oils, stains and sealers. All of these have their own benefits and drawbacks which is why it’s important you know what you want before choosing one.

In this article we will compare the different types of deck sealer on various dimensions so that you can make an informed decision about which type is best for your situation!

Why should we treat our decking?

Wooden decking needs to be sealed for it to last longer and look better.

Natural wood dries out and gets damaged by the weather and through use. This can shorten its lifespan and ruin its vibrant visual appeal.

Types of decking sealant available

There are many different types of deck sealers available for purchase in stores or online.

The type of deck sealer you use will depend on your needs – if you want to protect against water damage, choose one with a high waterproof rating 

Decking sealer

Deck sealant is a clear coat that seeps deep into the wood and forms an imperceptible film on its surface while preserving the natural finish of your deck.

By penetrating the wood, this sealer creates a protective layer that helps minimize water infiltration and lock out moisture.

This preventative finish is crucial in reducing fungal growth and wood rot – both of which can shorten your deck’s lifespan.

Ronseal Decking Protector Natural Oak

Raincheck Universal Water Seal

Decking stain

Deck stain is a great way to protect your wood from water damage, and it also provides the ability to change the colour.

The amount of pigment that gets added ranges in opacity from semi-transparent all the way up to solid colours for you.

There are many different tones available so be sure chosen one fits with what’s going on around your deck!

If you’re looking to get the most out of your deck, adding a dark stain is an excellent way to do so. When it comes down to blocking UV light and providing more protection overall, nothing beats having darker stains on hand.

Cuprinol Anti-Slip Decking Stain


Decking oil

Decking oils nourish the wood, giving it an enhanced natural finish. Once applied, these oils penetrate deep into the pores of your deck board and protect them from water damage or even warping.

Decking boards will also resist scratches on their surface for longer periods if this oil is used regularly.

Some users have noted that they slightly darkened some areas of their decking with regular use because removing all those old deposits left by weather over time replaces them with shiny ones instead.

Colour changes are pretty subtle upon first application, so this shouldn’t be too much cause for concern.

If you are going for decking oil check out our helpful guide to applying decking oils.

Ronseal Decking Oil Natural

Liberon DOCL5L 5L Decking Oil – Clear

Water based vs oil based sealants

Water based sealant

The most common type of decking sealant is water-based. These can be applied as liquids, while oils are usually thicker and require some amount of gunk to apply them onto the wood correctly.

Water based decking sealants are popular because they are usually affordable and easy to find.

They also dry quickly, which is an attractive quality when you don’t want to have any paint or sealant on your deck for long periods of time.

However, water based products can be seen as not being the easiest product because it has a tendency to run if applied too heavily. They also tend to need more regular coats of sealant to maintain the protective quality.

Oil based decking sealant

Another type of decking sealer is oil-based, which has a variety of benefits for those looking for protection and longevity over time.

The oils are usually thicker than water-based products so they provide more protection and last longer with less coats applied.

The advantage with oil-based types will depend on how much work you’re willing to put in: they take a lot more effort to apply but they last a lot longer and provide better protection.

One of the biggest disadvantages with oil types is that it’s important not to overuse them: in some cases, too much can darken or discolour your decking – especially if you have wooden boards which are already lighter

Comparison of types of decking sealant

UV protection

The vibrant colour of wooden decking eventually fades when ultraviolet radiation from the sun is able to penetrate deep into the cells of wood and cause a reaction between naturally occurring acids, sugars, and organic substance in the cell walls.

This is particularly true of darker colours and softwood decking.

The most effective products keep as much of the UV rays out as possible.

Generally speaking decking stain will be the most effective at UV protection as it is specifically designed to shield the wood from UV rays, while oils and sealers are not.

UV-resistant products will help keep your decking looking new for longer.

Longest lasting

Softwood decking has an expected lifespan of 15 – 30 years when it is sealed and treated properly. The lifespan of your decking will largely depend on how well you prevent it from ageing.

All types of decking sealer can help to improve the lifespan of your decking, but the best products will have a higher ratio of natural ingredients and need application least often.

Oil typically lasts about one year before needing reapplication, while a stain can be re-applied every two years or so.

The issue with stains and some other types of seal is that they only partially wear off over time which means when you come to reapply the seal it can end up with dark patches where the previous years stain is still holding on.

In short, if you are looking for the least amount of work you will be best going for a decking stain in the long run as it tends to last much longer and doesn’t need to be re-applied.

Waterproof rating

Water getting into your decking is the primary cause of damage to most decks. It soften the wood, allows the growth of algae and moss and makes the wood decay.

The water proof rating is often quoted as a percentage and rates how well the sealant will stop moisture from getting into your decking when it rains. The higher this number, the more waterproof your sealed deck will be to rainwater.

Choosing a very high-quality sealer with an excellent water resistant level will not only keep your deck looking great but it will also last a lot longer.

A sealer should typically have a water-proof rating of three or more hours and be able to withstand temperatures from -40 degrees Celsius up to 50 degrees Celsius.

Environmental friendliness

Some man made decking sealants can be a little harmful to the environment as they may contain chemicals that can’t be broken down by bacteria and fungi.

This is why it might be a good idea stick with natural oils like teak or cedar oil which are environmentally friendly and will not cause any problems for your decking in the future.

If you want something more environmentally-friendly then look at oils or stains which are typically made of plants oils like linseed and tung oils along with a solvents such as turpentine that evaporates when dry.

Generally speaking wood oils will be the most environmentally friendly choice of the options available.

Best looking

Perhaps the most important question is the type of finish you prefer for your decking, as either an oil or a stain will offer different types of shine and colour which can have a big impact on what appearance you are going for with your finished product.

Oils are my personal favourite as they bring out the natural grain of the wood as well as shining it up to an impressive sheen.

Oil is also easier to apply and less expensive than stains, which can be a big deciding factor depending on how much money you have available for your project.

Stains are great if you want something that will alter the appearance and finish of your decking.

Stains can give a rich , deep colour to the wood, which can have a striking effect. However they are difficult to apply and more expensive than oils since you need two coats of stain for full coverage instead of just one oil coat.

Stains may also pose an environmental danger as it is not biodegradable like most sealants.

How often should you decking sealant?

Most wooden decking is pressure treated when purchased. Pressure Treated wood has been chemically treated to protect it from decay, but still needs outside protection.

Pressure-treated decking will significantly reduce the need for washing and aerating because it has a higher degree of tolerance against rot and insect damage.

You should wait around 6 months after your decking is installed before applying any stain at all.

If your decking is not pressure treated the wood should be re-sealed at least once a year and more often if it has been exposed to heavy rain, strong UV rays or severe weather conditions.

If you are using decking oils you should apply them annually, for stains and sealers you will need to apply them between every 2 and 4 years depending on the type.

It’s important to use the right sealant for your decking material, and it is also vital to maintain good housekeeping practices on the surface around your deck such as removing dirt with a soft brush before applying any products so they have maximum effect.

How to tell if you decking need resealing

Decking which needs resealing because its looking a bit old

You can tell when your decking needs resealing if it looks faded, has a dull or patchy appearance and feels rough to the touch.

Should I get a professional to do this for me or can I DIY it myself

This really depends on how handy you are, the state of your decking and what the work will involve.

Decking oils are easy to apply, but you may need to brush it on with a paintbrush.

Decking sealers are usually applied by spraying and take about 30 minutes to dry before being walked on.

If you have the time and patience for DIY deck care then it’s worth giving it go yourself because this is one of those jobs that gets easier after each application.

However if your outlay isn’t unlimited or you don’t want the job done less than perfectly, get in touch with a professional cleaner like Miracle Sealants who can give your old boards new life by applying their fabulous products.

If you have a hardwood decking such as Iroko or oak it is highly recommended to do you research and consult a professional before treating them with anything. See our article on the different types of wooden decking.

To conclude

The best decking sealers will vary depending on what your needs are but it is important to find a product that fits all of these criteria. The best product for you will depend on your needs, budget and time constraints.

If you want to prioritise the rich look of natural wood then you will want to go for a natural oil like linseed, although it is important that you also clean the boards of dirt and dust before applying the sealant.

If environmental friendliness is your priority then an eco-friendly product like decking oil will work well too.

If you are looking for something with longevity but don’t care about how shiny your deck looks or its overall appearance then a strong sealer or stain will work.

No matter what type of wood treatment you choose, make sure it has UV inhibitors in because this reduces discolouring from sun exposure.

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