Shed Preserver

Why use a shed preservative?

Buying a garden shed is a big investment and it makes sense to spend some time protecting the wood with a shed preserver. After-all, its going to have to withstand the hottest and driest of summers and the wettest and coldest of winters for as many years as possible.


Applying a wood preservative to a garden shed helps to protect the timber against mould, algae and insect attack. In addition, many wood preservers also contain a small amount of wax which offers some limited protection against weathering including wind, rain and sun.

To seal the shed preserver in to the wood grain and provide the shed the best possible protection, it’s always recommended that once applied, any preservative is over-coated with a suitable top-coat such as an exterior wood oil, shed paint, shed stain or shed varnish. This will help to ensure that your shed will last year after year and potentially for decades if well maintained.

Types of shed preserver

Wood preservatives come in many guises but essentially, they all do the same job. Even those that are marketed specifically for sheds and fences are just the same as those that aren’t. Most brands produce both clear and coloured versions in either solvent-based or water-based formulas. Some types contain a small amount of wax whilst others do not.

Solvent-based vs water-based shed preservers

A question often asked is ‘are water or solvent-based shed preservatives best?’ Truth is that both types contain the same key preserving ingredients. Although solvent-based wood preservers tend to have better penetration, water-based preservers are more user and environmentally friendly. Both can be overcoated with an exterior wood oil or log cabin treatment to seal in the preservative and protect the structure from the effects of weathering.

What is the best wood preservative for sheds?

So which is the best wood preservative for sheds? This largely depends on what type of look or finish is required. To keep the shed looking natural, use a clear wood preservative and overcoat with a clear exterior wood oil or decking oil for the best protection. Sheds can be easily stained or coloured by using a coloured wood preservative then over-coated with a clear wood oil or clear decking oil. Alternatively, a clear preservative can be used then a coloured decking oil or coloured wood oil can be applied.

If using a water-based garden paint or shed paint, take care to ensure that any wood preservative used does not contain wax, silicon or oil as these will potentially repel the paint from the surface of the shed and prevent adhesion with the wood.

Recommended Shed Preservers

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Other shed treatments

Although wood preservatives are essential for protecting shed timbers from biological threats such as mould, algae and insect attack, for the best long term protection, it is recommended that sheds are first preserved then treated with a clear exterior wood oil such as Barrettine Log Cabin Treatment or a clear decking oil. Applying a wood oil over the preservative extends the effective life of the wood preservative and provides excellent weather protection. The oil also keeps the shed timbers nourished and supple, therefore helping to prevent cracking, splitting and warping over time. To maintain the finish, simply reapply a fresh coat of wood oil as and when required to maintain the sheds weather resistance and appearance.


Those of a certain age will remember when anything wood in the garden used to be treated with Creosote. The sale of Creosote is now regulated and can only be sold to farmers and for other industrial uses.

The good news is that there is a safer, more environmentally friendly version called ‘Creocote’. This oil based Creosote substitute is perfect for use on garden sheds and fences.

Shed Paints

Painting garden sheds has never been more popular, turning otherwise uninteresting structures into stand out, trendy garden features. From pale blues and pinks to modern grey and subtle greens. One thing to keep in mind is that many shed paint products are water-based, it is therefore important to ensure that if preserving the shed first, the preservative does not contain any wax, oil or silicon as this will repel the paint and prevent it from adhering to the shed.

Find out more about shed paint colours, types and recommendations here

Shed Cleaners

Mould and algae can be a particular problem for garden sheds that are located in dark corners or surrounded with bushes and trees. characterised by black or green stains or the appearance of physical growth, mould and algae can degrade shed timbers if left untreated. Using a dedicated mould and algae cleaner to remove and kill the spores in the timber prior to applying a wood preservative is essential. Although shed and wood preservatives help to prevent the development of mould and algae, they will not kill off existing infestations.

Find out more about shed cleaners, mould and algae treatments here.