5 top wood preservers to protect & preserve


Everyone has heard of wood preservers but what are they, why are they so important and how do they work?

Although wood is an amazingly versatile and durable material, it can be susceptible to deterioration, especially so in environments where mould, algae, fungi and wood-boring insects are likely. The best way to protect and preserve wood, including timbers that have been tanalised or pressure-treated is to use a wood preservative.

Old garden shed suffering from rot and decay
A neglected garden shed that has been allowed to rot and decay.

In past years, sheds, fences, railway sleepers and other exterior wood were treated with creosote, engine oil or other preservatives that contained commercial grade biocides and insecticides. Over the decades, as a greater understanding of the toxic nature of these products became known, many were banned or restricted for commercial use only by strict government legislation. Thankfully, todays domestic wood preservers, although still toxic if misused, are generally safer for both the user and environment.

Types of wood preservative

Because of tightening legislation on the ingredients that can be used, most wood preservatives are now based on similar formulas. They may have slightly different formulations and ingredients, but they all work in a similar way to protect wood from environmental threats. From a user perspective the deciding factor usually comes down to whether a clear or coloured preservative is needed and if a water-based or solvent-based formula is preferred.

Clear preservers help to retain the natural appearance of the wood whilst coloured versions act as a dual-purpose wood preserver and stain. Most preservers were traditionally solvent-based but more and more manufacturers are changing these to water-based formulas to conform to strict V.O.C (Volatile Organic Compounds) regulations being imposed by UK, European and Worldwide governments.

Why use a wood preservative?

In short, wood preservers help to prevent many of the conditions that can cause the degradation and disintegration of wood over time. Using a wood preservative protects wood from mould, algae, fungi and wood boring insects, the most common causes of wood rot and decay. Wood that has been preserved, treated with a suitable top-coat and maintained will last for decades or longer.

How do wood preservers work?

The key ingredients of wood preservers are biocides and insecticides with the most commonly used being Permethrin. Permethrin is an insecticide in the pyrethroid family. Pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower. Other common ingredients include Iodo propynyl Butylcarbamate and Tebuconazole. Most modern wood preservers are safe for humans, animals and plants when dry, meaning that they can be used on sheds, fences, wooden trellis, dog kennels, stables, joinery and more.

Are wood preservers an all-in-one solution?

Although wood preservers are great at protecting wood from biological threats, they only offer limited weather protection and direct contact durability. Some wood preservers contain a small amount of wax which means that rainwater will initially bead and run off treated wood. Surfaces treated with just a wood preservative however, will likely need re-coating every year or 2. Ideally, wood that has been treated with a preserver should also be treated with a suitable top coat such as an wood oil, wood paint or wood varnish. These top-coat products seal in the preserver and provide protection against weathering and wear from direct contact.

If overcoating a wood preservative with a water-based paint or varnish, it’s important to select a preserver that does not contain wax.

5 of our top selling wood preservers

Although we sell dozens of wood preservatives, here are just a few of our best selling products.

Barrettine Premier Wood Preserver

A solvent-based exterior wood preservative that offers microporous protection against wood rot, fungi, decay and mould. Available in clear and an attractive range of wood tone colours.

Barrettine wood preservers for exterior wood
Barrettine Wood Preserver for exterior timber – Ideal for garden sheds, fences and more.

Customer Review – Barrettine Premier Wood Preserver

The product is easy to apply, provided you don’t overload the brush and soaks into the wood. The boards on the house had two coats 3 years ago and still look good with little sign of green fungus (shady side). My neighbour has now decided to use it on his property.

Ronseal Total Wood Preservative

A highly penetrative, solvent-based wood preserver for exterior timbers. Perfect for use on garden sheds, fences, joists, doors and window frames.

Ronseal Total exterior wood preserver
Ronseal Total Wood Preserver – Available in clear and a range of colours for exterior wood

Customer Review – Ronseal Total Wood Preservative

Used for both my deck and my fence. Good coverage and easily applied using a brush. Natural colour which brings out the grain. Would recommend.

Cuprinol 5 Star Complete Wood Treatment (WB)

A clear, water-based, all-in-one wood treatment for interior timber. Deep penetrating formula ensures effective treatment and lasting protection against insect attack, re-infestation and fungal decay.

Cuprinol Complete 5 Star Wood Treatment for interior wood
Complete wood treatment for interior wood including floor boards, joists, joinery and more.

Customer Review – Cuprinol 5 Star Complete Wood Treatment (WB)

I ordered this product as I needed to apply a thin coating that got absorbed readily on old interior timbers and new Oak beams alike. Little evidence of any staining which was important. Applied via a spray nozzle and also a brush. Low odour and lasted a long time.

Osmo Wood Protector (4006)

A wood protective treatment that is free from biocides and preservatives. Ideal for treating wood in high moisture areas, such as wet rooms, kitchens and bathrooms. Especially suitable for woods that are susceptible to blue stain, such as Pine.

Osmo 4006 Wood Protector for interior wood
Osmo Wood Protector 4006 – A biocide and preservative free wood protector, ideal for interior, high moisture environments.

Customer Review – Osmo Wood Protector (4006)

I can only say that I needed an undercoat to protect the bathroom wood door from steam, moisture and similar. So using the Osmo brand made sense before using Osmo oil.

Sadolin Quick Drying Wood Preserver

A clear water-based wood preserver suitable for new and bare timber. Perfect as a pre-treatment before applying a wood stain, paint or other wood finish. Provides excellent protection for interior and exterior joinery against wood destroying fungi and blue stain.

Sadolin Quick Drying Wood Preserver - Wax free clear wood preservative
Sadolin Quick Drying Wood Preserver – A wax free clear preserver.

Customer Review – Sadolin Quick Drying Wood Preserver

A great product that goes on easily. It’s protecting my log cabin even before I get round to getting the top coat on. Good preparation should result in a long life.

Top wood preserving tip!

All wood, new and old should be treated with a fungicidal wash or multicide wood cleaner before treating with a wood preserver. Why? Wood only needs to get wet or damp once for mould and algae spores to establish themselves in the wood grain. This can happen at any time in the transit or storage of the timber or the finished article including sheds, fences and decking boards. Although wood preservers will help to prevent mould, algae and fungi establishing itself on the wood, they are not always effective at killing off already established spores within the timber.

For this reason, we always recommend that all wood is initially treated with a fungicidal wash or mould and mildew cleaner to kill off any existing spores in the wood grain before applying a preserver.

Want to know even more about wood preservers?

For more information about wood preservers 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 wood preserver FAQ page which covers many of the most commonly asked questions about wood preservers.

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

Other great blogs that discuss wood preservers

  • How To Preserve a Fence Panel So it Will Last! – Ronseal Total Wood Preserver
  • Wood Preservation – Getting Your Garden Shed Shipshape

    1. Hello – I have a log cabin that has been treated with a single coat of Blackfriar Wood Protector

      What would be a good product to use as a top coat? I’ve been recommended Sadolin Classic but like the colour of the cabin so would something like Sadolin Clear Coat be suitable?

      Thank you.

      • Hello Simon,

        The Blackfriars looks to be a preserver that contains wax, this is what gives it the moisture repellent element. This means that not all products will adhere well over the top and I think Sadolin is likely to be one of those products.

        As a general rule for exterior finishes, if you want to use a paint, varnish or top coats stain, you need to use a wax free preserver. Preservers that do contain wax can be used as stand alone products for fencing for example or if you are applying an oil over the top.

        For Log Cabins I do tend to recommend an oiled finish anyhow, oils penetrate the wood and will not peel and flake down the line. Its fair to say they are not as long lasting as some stains or paints, however the benefit comes with ease of maintenance. No stripping required just apply a fresh coat a clean dry surface when the wood needs it, usually annually or bi annually. I recommend the Barrettine Log Cabin Treatment as a good option to consider.

        If you did want to go with a Sadolin Extra Durable Clearcoat its best to try a test area first and see if the product will adhere to the surface of the wood, bearing in mind that if it does there will be no guarantees for longevity, or wait for a period of 6 months for the wax to naturally start to wear and then consider application.

        Its also worth bearing in mind that application of a clear product, oil or varnish, offer little UV protection whereas the application of a colour, even a very light one will greatly reduce the silvering from UV damage.

        I hope that helps and please do get in touch with the team via our contact us page if you have any questions.

        All the Best Samantha.

    2. My tongue and groove pine cladding on my summer house needs treated do I stain a colour first then apply a clear oil such as osmos or barratime? The front sees a lot of sun.

      • Hello Marc,

        Great question, you do have a few options for this project. A coloured preserver and clear oil or a clear preserver and coloured oil. Both options will give great protection from the sun and also from the rain. Which to go for can simply be down to the colour you want to achieve.

        For a clear preserver I often recommend the Barrettine Premier Universal Preserver because it does not contain wax it is great for what ever top coat you want to apply, oils, paints or stains. It is a clear preserver and so the colour can come from a product such as the Osmo Natural Oil Woodstain or alternatively a coloured Decking Oil, perhaps one of the Barrettine Decking Oils if there is a colour with in that range you like.

        The darker the colour the better the UV protection, however even with a lighter colour the results will be good and the benefit of oils is they are easy to clean and maintain over time.

        For a coloured preserver Barrettine Premier Wood Preserver followed by a clear oil such as the Barrettine Log Cabin Treatment.

        With the combination of two products you tend to get a better over all level of protection and its only the top coat of oil that will need maintaining for a few years, as long as you look after the finish.

        If you want just a one product finish then the Premier Wood Preserver can be used as a stand alone product with 3 coats applied for the best protection.

        I hope that helps please do get in touch if you have any questions, via our contact us page. And as always try a test area first.

        Kind regards Samantha.

    3. I have moved to a house with a wooden porch which is made of Idigbo timber, installed about 10 years ago. I don’t know how it has been maintained but looks in reasonable condition with no rot. What wood preservative and pre-treatment would you recommend I use? I would like to use a solvent based clear finish.

      • Hello Alan,

        Thank you for your question. Idigbo is a very durable wood in its own right, even with out a treatment applied. A hard wood resistant to decay and is quite stable over time with little movement.

        If the wood currently appears to have no treatment applied then a preserver such as the Barrettine Premier Universal Preserver is a good place to start, this is a clear product that will help to prevent any decay or rot, it will darken the wood some, more if it is dry and silvered.

        Then you could consider a clear oil, although many products claim they are not suitable for Idigbo, this is because it can often leach yellow when the wood becomes wet and can discolour or stain. However with the age of the wood I would expect you to be able to get an oil of some kind on there, and you could perhaps take a look at a Barrettine Teak Oil as an option, ideal for hard woods and very moisture resistant.

        I hope that helps, if you take a look at the recommendations and see if they may suit your needs and do feel free to get in touch via our contact us page if you have any further questions.

        Kind regards Samantha.

      • Hello Pete,

        Thank you for your question, I can reassure you that all preservers are safe once dry. When in their wet state they could damage plant life and be harmful to humans and animals if ingested, so care should be taken at the application stage. However once dry on the wood there is not risk to human, animal or plant life. The only real exception is aquatics, of which no products are recommended other than those specific to aquatic use.

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

        All the Best Samantha.

    4. Hello. My son made me a wonderful garden seat from various wood including some pallet and decking pieces. It needs protecting before I put it in the garden but I have Multi Chemical Sensitivities and cannot cope with voc’s, even when they are just ‘lingering.’ I would hate to use something that would cause problems and result in my not being able to get near the chair!
      I would appreciate some advice as to what might preserve this precious seat. TIA

      • Hello Carron,

        Thank you for getting in touch with your enquiry. Many and most products for the exterior will contain biocodes to help prevent mould. We often recommend a Preserver for exterior woods to help prevent rot and decay from occurring, these are likely to be unsuitable for you health wise.

        So you are likely to need to skip this stage of protection, it will leave the wood slightly vulnerable, however a regular clean will make all the difference. To give the wood some protection against the weather a water based paint, may be the best option for you, these tend to be lower in VOC although they are not free of.

        Ronseal Garden Paint is a great option to consider and has a lot of colour options and also Cuprinol Garden Shades are probably the best to choose from. Both are available in sample sizes and so if you are unsure then perhaps see how you get on around the samples first.

        I would say that once fully cured all products from our website are safe and so even if you went for something with a little higher VOC if you are able to treat and leave for a few weeks before using this may also help.

        I can give no guarantees as to what will work best for you, those samples sizes could be a great help for you however and for more help and advice please feel free to get in touch via our contact us page.

        Kind Regards Samantha.

    5. Hi.
      I’m doing some double garage doors, some cladding over the old window’s and along the side of the garage and a side gate too, I’m using new match tongue and groove board’s, can you please tell me what I need to get and do before I start please. The finished colour will most likely be a summer tan or similar!
      Many thanks

      • Hello Keith,

        Thank you for getting in touch with your question. It would be good to have a product or set of products that you can use for all these projects and I would recommend taking a look at a couple of options, both require a preserver and top coat and both will protect all areas of your wood.

        For all exterior projects a preserver is recommended first, this helps to prevent mould, decay and rot in the wood. And you could take a look at the Barrettine Premier Protective Treatment this is a bit like an all in one product that has some biocides in for preserving, and builds to a surface sealer for exterior wood, it is a cost effective option and can be topped up when needed.

        And from Sadolin there is the Sadolin Quick Drying Preserver followed by coat of the Sadolin Classic Wood Protection and then one or two coats of the Sadolin Extra Durable Woodstain.

        This will give longer lasting, better protection to your wood and with occasional care and maintenance can protect for many years to come. If you take a look and have a read of the products to see if they will suit your needs and feel free to get in touch via our contact us page if you have any other questions, I am happy to help.

        Kind regards Samantha.

    6. Dear Sir / Madam, I have just purchased a Victorian property that has timber-framed windows. The timber windows are about 20 years old. I have been advised by the surveyor that as the timber windows are constructed of hardwood and in fairly good condition, I should retain and maintain them as oppose to replacing them. However, there is slight damage to the 2 window sills due to condensation. Ideally, I would like to preserve them for as long as I can but which products would you propose. I am inclined to go for the Sadelin range. I can apply the Sadelin classic first; leave it for 16 hours before applying the Sadelin extra followed by a second coat of Sadelin extra after 16 hours. However, the wood surface needs to be cleaned beforehand. What can I used to clean the window frames so that any underlying microbial spores can be destroyed?
      Although I’m thinking of using Sadelin as a wood preserver, I am open to suggestions. I look forward to hearing from you. Cheers.
      Adam 0745 329 0002

      • Hello Adam,

        Thank you for getting in touch, although it sounds like you have everything in hand. The Sadolin range is a good option to go for with exterior projects. It is very durable and gives a really attractive finish. As you are considering the Sadolin Classic Wood Protection and the Sadolin Extra Durable Woodstain , it makes sense to stick with a Sadolin Quick Drying Preserver

        I would recommend a good clean with some Methylated Spirits before hand, this will degrease, remove any residue or natural oils in the wood and prep for better adhesion. Test areas are vital to ensure you are getting the desired result.

        And if you need any further help or wish to share the results of your project, please do not hesitate to get in touch via our contact us page.

        All the Best Samantha

      • Good Morning Peter,

        We have a wide range of product that can be used for your project and so if you can get back to me via our contact us page, with details about what look you would like to achieve? Opaque or transparent? Natural or coloured? And I can narrow down some suitable options for you to consider.

        Many Thanks Samantha.

    7. Hi,
      I have a new shed, I thought it had been treated so I stained it. The rain came and soaked right through from outside to inside. Which product do you reccomend to keep the outside waterproof?

      Thank you

      • Good Morning Dawn,

        I am sorry to hear that you have had this issue. The structure of the shed, in itself, should keep any rain or moisture out, even before any product is applied and it is worrying that you have had this problem.

        When you apply a wood finish product, it is purely to protect the wood and repel moisture from the wood, and so prevent mould and rot from damaging the wood. Paints, stains, varnishes and oils are not designed to seal the structure of the shed, and prevent water from getting in and I would perhaps get in touch with the shed manufacturer or supplier to see why this has happened.

        I would also be happy to take a look at any photos you would like to send along with details of the product you have used to the contact us page.

        kind regards Samantha.

    8. I have used Cuprinol clear water based wood preserver on some new garage doors.
      Can I now use sadolin classic sprit based top coats?

      • Hello Simon,

        If you have used the wax free preserver then yes you should have no issue with application of the Sadolin over the top. As with any advice, I always recommend that test area, to make sure not only that you like the result to be achieved but also that there is no adverse reaction.

        All the Best Samantha.

    9. I have an old Japanese cabinet that has been in storage for some time , dampness has affected the dry finish and affected the glue. I can stick the loose joints together and clean the carved ivory and mother of Pearl but need to treat the Wood. I used a wet cloth to remove the dirt but it has removed some of the old finish which was a brown colour I thought was teak. What would you suggest I should use to treat the Wood?

      • Hello Rory,

        This sound like quite a specialist piece. I would be happy to see if I can make some suggestions for you to consider, but I do think I need to see some images of the item and the current colours and condition, in order to make the best suggestions. You can email photos over to me at wfd.advice@wood-finishes-direct.com and we can go from there.

        All the Best Samantha.

    10. Can you suggest a preserver/stain for Tanalised Gates made from soft wood. I’ve used Cuprinol Ducksback (5 year Guarantee) on a previous set of gates and was not impressed at all. These new gates (direct from manufacturer) are waiting for me to apply some sort of treatment before I fit ironwork and hang . Ideal colour would be Forest Green.

      • Good Morning,

        Exterior woods are so exposed to all the element and it can be difficult to give a long life protection even with the best products. Often we recommend oils as these penetrate the wood and will not peel and flake over time. They do not last as long as some other products, however a refresher coat can be applied to clean dry wood, when needed, with out the need to strip back to bare wood.

        For a green exterior oil, you could have a look at the Holzol Weather Oil or you can achieve that colour by using a green preserver and then applying a green or clear top coal of the oil.

        I hope that helps and for further advice please feel free to get in touch via our contact us page

        Kind regards Samantha.

      • Hello Gerry,

        Sorry to say this is not one that we supply either. It may have been discontinued. if you get int ouch with Ronseal directly they may be able to tell you if it is available and if so where you are able to get it from. 0114 2409 469 or enquiry@Ronseal.co.uk

        Kind Regards Samantha.


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