Protecting wood outdoors

The complete guide

Date: 6th May 2020
Categories: Barrettine

Protecting wood outdoors

From potting shed and picket fence to luxurious log cabin, wooden structures play a big part in garden design.

They provide privacy, a feature and valuable extra space and, when it comes to moving on, add value to our homes.   But whilst wood is robust and resilient, a little care and maintenance will do it wonders.

The treatment options

Wood care treatments come in many forms and selecting the right product can be confusing. A structure’s age, function and timber-type will help determine which is the best treatment for the job.  As a rule of thumb, outdoor wood protectors – often used on pre-treated timbers - protect against the elements, whilst wood preservers protect timber from wood boring insect attack and fungal decay, including ‘blue stain’.

Wood Treatments

About protectors

Protective Treatment

Protectors are most commonly used on fences, sheds and other external structures.  Barrettine Wood Protective Treatment is an ideal option for all types of pre-treated rough, sawn or smooth timber.  As a wood sealer, it contains water-repellent and UV-fade resistant pigments and resins, creating a semi-transparent finish allowing the woods natural features and grain to show through.

It also contains a ‘film biocide’ which prevents the surface growth of mould and algae, whilst also reducing wood decay, swelling and twisting.  As the treatment doesn’t contain an insecticide, it is insect-friendly once dry.   If you’re painting/treating wood that’s in close proximity to established flower beds and shrubs etc, Barrettine recommends its water-based Shed & Fence Treatment.


Before applying the protector, any dirt, mould and algae should be removed with a stiff brush, broom or scraper. The treatment can then be applied by brush, roller or solvent compatible low-pressure sprayer. Two or three coats will provide the best protection; allow at least six hours drying time between coats.  Initial treatment with Barrettine Mould & Mildew Cleaner may be necessary if the timber is badly affected.  If the timber has been previously painted or varnished, the surface will need to be stripped or sanded back prior to application of Barrettine Wood Protector. Going forward, a fresh coat of protector can be applied with minimal preparation required other than wiping the surface clean of debris/dirt.

Protective boards


About preservers


Preservers are generally used outdoors, applications would include inner and outer frames of external joinery, doors, windows, facades, carports, shutters, summer houses, gates and are also suitable for wood resting on the ground such as garden furniture. Some internal applications can also include structural timbers i.e. roof / floor joists that are not left exposed in any living quarters.

Based on internal testing, Oil based products when compared to water-based treatments penetrate more deeply, offering greater protection and longevity like Barrettine’s Oil based Wood Preserver, which is offered in a range of eight colours including clear.


An alternative product Barrettine offer is the Log Cabin & Complete Decking Treatment which is specifically formulated to oil and protect log cabins, decking boards, deck tiles and balustrades made from pre-treated, pressure-treated or preservative impregnated timber. This is not a preserver but will deliver a superior finish and help protect your outbuildings. The product is only available in clear so it will not stain leaving the woods natural features and appearance to show through.  The Log Cabin treatment contains a film/surface biocide that will help prevent mould growth on the surface for a short period of time, but untreated timbers should be protected first with Barrettine Universal Preserver. This product will help defend timber against wood-destroying fungi (wet rot), wood discolouring fungi and wood-boring insects.


Don’t forget the decking

Worn and weathered decking will also benefit greatly from annual treatment.  Oil protectors are much easier to use to maintain decking as they won’t peel and crack like a decking paint. A quality decking treatment will help repel water and prevent the timber from splitting and cracking.  Treatments like Barrettine’s All-in-One Decking Oil also contain UV inhibitors and fade-resistant pigments, so they help prevent discolouration/bleaching and a gradual fade to grey.  The All-in-One Decking Oil also contains a ‘surface biocide preserver’ which protects against surface mould.  

As a further step, it’s well worth applying a top coat, like Barrettine’s award-winning Anti-Slip Decking Oil, to improve grip.  Tiny organic particles within the oil create a slight texture which improves friction and grip between shoes or bare feet and the surface of the timber.  Barrettine’s Anti-Slip Decking Oil also provides further protection against the elements and helps slow discolouration, so the benefits stack up.

All of the Barrettine wood care treatments are safe for children and pets when dry.  Biocidal preservers are, however, dangerous to aquatic life, so they should not be applied near ponds. Always follow the label instructions.

To purchase any of the products listed above and enter our promotion for FREE 'Unwins' Poppy Seeds or to be in with a chance of winning £1000 of Luxury garden furniture click below. 

Terms & conditions apply.

All press releases