A common issue with garden fence panels is the development of mould, algae, fungi, or other biological growth. This is more common with garden fences situated in shaded or damp conditions, and can eventually result in wood rot. So how do you protect fence panels and posts, to protect them from mould and algae, and to keep them looking good and lasting longer?
Fence panels affected by Mould & Algae | Half treated with mould and mildew cleaner and half not
Why clean mould and algae from garden fence panels?
In short, apart from looking unsightly, any type of biological growth that forms on wooden fence panels will eventually promote wood rot and decay, shortening the life of garden fences. Using a dedicated fungicidal wash or mould and mildew cleaner will not only remove and clean the growth from the wood, but will also kill off any active or dormant mould spores in the surface grain of the timber, therefore helping to prevent re-growth.
Simply re-treating fences with a fence paint colour, fence stain or oil-based fence treatment, without treating any mould and algae first will simply result in the green growth remaining or growing back quickly. This will very quickly spoil the appearance of the fence after all the hard work to paint or stain it.
Top 4 Recommended wood and fence cleaners
- Pro-Kleen Spray and Walk Away Green Mould and Algae Killer: A super powerful outdoor green mould and algae remover that cleans and revives patio, decking, fencing, outdoor furniture, and more. Is safe for children and pets once dry!
- Roxil 100 Green Mould, Algae & Lichen Killer: A powerful Mould, Algae, Lichens and other biological growth killer. Also available in a kit that comes with the Roxil 100 Green Mould, Algae & Lichen Killer and a pump action sprayer for easy application.
- ULTIMA-PLUS XP MY1356 Patio Cleaner & Green Mould And Algae Remover: A powerful and concentrated wood and other hard surface cleaner. One 5L bottle makes a minimum of 25Ltrs of solution covering a huge 200m² area.
- Dirtbusters Spray Today Gone Tomorrow: Patio Decking Fence Drive Cleaner extra strength formula which removes Mould Mildew Moss Algae Lichen Killer Green Growth Remover
Garden pump sprayers
By far the quickest and easiest way to treat large areas of fencing affected by mould, algae and other biological growth. These inexpensive sprayers can cover large areas in a fraction of the time taken to brush apply. They can also be used afterwards for other purposes and uses but if using to treat or water plants, they must be cleaned thoroughly. Any traces of mould and mildew cleaner or fungicidal wash sprayed on to plants will likely harm or kill them.
Top 3 Recommended garden pump sprayers
- Spear and Jackson Pump Action Pressure Sprayer, 5 Litre: A highly versatile garden pump sprayer with a fully adjustable wand nozzle and water flow regulator. Translucent graduated bottle in litres and fluid ounces for accuracy when filling or mixing within the bottle
- Ansio Pressure Sprayer: Pump action, weed killer, water pump sprayer, ideal for Pesticides, Herbicides, Insecticides and Fungicides
- VOXON 5L Pump Action Pressure Sprayer: Fully adjustable wand nozzle from spray to mist, lockable trigger mechanism and water flow regulator. Translucent graduated bottle in litres and fluid ounces for accuracy when filling, or mixing within the bottle. 5 litre pump action pressure sprayer with pressure release valve and shoulder strap. For use with water & non-viscous water-based or soluble products including pesticides, herbicides, insecticides, fungicides, and fertilisers
Once treated, fence panels and posts should be treated with a clear or coloured fence preservative to prevent future instances of mould, algae, wood rot, and insect attack. If the fence is to be treated with a water-based garden fence paint or stain, it is important that any wood preservative used does not contain wax, oil, or silicon. Wood preservers that contain wax or silicon will repel any water-based treatment and prevent it from adhering with the wood.
Other fence treatments and top coats
- Wooden fence preservers: Available in clear and coloured formulations, water and solvent-based, this is the next step once fences have been treated and cleaned of any mould, algae, lichens and other biological growth
- Oil-based treatments for garden fences: Exterior wood oils seal in any preservative and protect fences from weathering and water ingress. Wood oils also nourish and feed the wood which helps to protect fence panel timbers from cracking, splitting and warping.
- Garden paints for fences: Garden paints are great for introducing colour and character to garden spaces. They colour and also protect the wood from weathering. Many garden paints are water-based so be sure to use a wood preservative that does not contain wax
- Garden fence stains: Garden fence stains are the popular choice from re-colouring and protecting garden fence panels that have perhaps turned grey or silver over time. Woos stains penetrate into the wood grain to colour and protect fences from weathering and UV damage.
Treating new fence panels
New fence panels don’t necessarily have to be treated as they are often delivered pre-treated or tanalised. This said however, there is no way of knowing how old the panels are or how they have been stored. If they have been damp or wet at any time, mould and algae spores can be present on delivery. For this reason and to offer the best all-round protection against biological threats and weathering, there’s no harm in treating new fence panels with a wood preserver and a top-coat of oil.
Old fence panels
Old wooden fence panels and posts that have black or green areas should be treated with the same mould and algae cleaners listed above. For garden fences that have a large surface build up of mould or algae, use a stiff brush, broom or scraper to remove as much surface matter as possible before treating. Heavily soiled fence panels may require a second treatment to fully remove any biological growth.
How to clean wooden garden fences
- Ensure that wooden fences to be treated are dry
- Where necessary, scrub with a stiff broom, brush or scraper to remove any surface mould, algae or other biological growth
- Treat the affected panels with a suitable fungicidal wash or mould and mildew cleaner such as those listed above
- Repeat the process if the fence is heavily soiled
- Once fully dry, apply 2 coats of an exterior wood preservative, clear or coloured, to give the fence protection against future instances of mould, algae, insect attack, and to protect against wood rot
- Allow the preservative to dry fully in accordance with the manufacturer’s instructions on the tin
- Apply 2 coats of an exterior wood oil or decking oil. This can be a clear oil-based fence treatment or a coloured one if you wish to stain the fence to restore or change its colour. two coats of preservative and two coats of oil will provide maximum protection
Find out more about fence care and maintenance, and the types of different fence protective treatments on our garden fence care and maintenance guide here.
Garden Fence FAQ’s
Can’t find the answer to your garden fence care or maintenance project above? See our frequently asked garden fence questions and answers page, where we try to answer some of the more commonly asked questions relating to garden fence care, maintenance, and fence treatments.