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 deck and fence. Good coverage and easily applied using brush. Natural colour which brings out 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 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. Its 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 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.


  1. 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.

  2. 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.

  3. 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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