Garden and DIY, cost per square metre per year
Fence care: cost per square metre per year
Fence treatment is sold on the price of the tin and the years on the label, and the usual advice is that the longer-lasting tin pays for itself. Count coverage and coats, and the cheap one coat product, redone more often, is the cheapest fence per year.
Some links on this page are affiliate links, which earn us a commission if you buy. It costs you nothing extra, and it never changes which option comes out cheapest here, because the ranking is arithmetic. How this works.
Per square metre, per year
The one coat fence treatment works out at 16.7p per square metre per year. The premium garden paint costs 34.3p, a factor of 2.1, with the five year treatment between them at 29.7p. So the tin with the shortest life on its label is the cheapest way to keep a fence covered, and the one with the longest is the dearest.
| Option | Running | Cost per square metre per year | Relative |
|---|---|---|---|
| One coat fence treatment£10 for 5L, 6 m² a litre, 1 coat, 2 years | 16.7p | 16.7p | |
| Five year fence treatment£18.59 for 5L, 5 m² a litre, 2 coats, 5 years | 29.7p | 29.7p | |
| Premium garden paint£36 for 2.5L, 14 m² a litre, 2 coats, 6 years | 34.3p | 34.3p |
The reason is coats. The one coat product is one pass for its whole life. Both longer-lasting products ask for two, which doubles the paint on the fence before the extra years are counted, and the extra years do not pay that back.
How the sum works
Every row is the same four steps: tin price over litres, over coverage per coat, times coats, over the years it claims to last.
The five year treatment lasts more than twice as long and still loses, because it costs nearly twice as much per litre, covers less per coat and needs two coats. Multiplied together, those outweigh the extra life.
What it means for an actual fence
A run of six standard panels has about 20 square metres on one face. Kept in the one coat product, that face costs £33.33 over ten years, against £59.49 for the five year treatment and £68.57 for premium garden paint. The gap is £4 a year: real, but not the sort of money that decides much on its own. Treat both faces and every figure doubles, without changing the order.
Every durability figure is the maker's claim, for a fence that is not in full sun, shaded by a hedge or splashed by a sprinkler. If every product falls short by the same proportion, the ranking holds. If the long-life products fall short by more, which reviewers of five year treatments commonly report, the cheap option wins by more.
What the longer-lasting tins actually buy
They cost more per year, and what they save is days spent doing it. Every visit has costs the table does not count: moving the pots, covering the border, cleaning the brush, the weekend itself. But each one coat visit is a single pass, while the others need two with a drying gap between, so the hours of brushing over a decade are much closer than the number of visits suggests.
Where premium garden paint earns its price
On a fence it is the dearest option even at its best-case coverage, and that figure is for an ordinary surface, not rough sawn boards, which drink far more. Its case is colour and finish on things people look at closely: a gate, a shed door, garden furniture. Those areas are small, so the premium is a few pounds, and the colour range is far wider than any fence treatment offers. Paying for the colour on a bench is reasonable. Paying it across a whole fence in the belief that it works out cheaper is not.
Treatment versus paint on the fence itself
A fence treatment soaks into rough timber and fades, so the next coat goes on after a brush down. Paint forms a film, and a failing film flakes, which means scraping first. That work is in none of these figures, and it lands on the option that is already the dearest.
The verdict
For a plain fence, the cheapest way to keep it coloured is the one coat treatment, redone when it fades, at 16.7p per square metre per year. The five year treatment costs more per year and saves you some weekends. Premium garden paint is the dearest way to cover a fence and earns its price on the small things you look at up close. Whichever you buy, check the coverage is for rough sawn timber and count the coats: the years on the front of the tin are the least important number on it.
Put your own numbers in
The consumable field is one square metre of fence for one year: the tin price, divided by coverage, times the coats, divided by the years it lasts. Put your own tin in.
Cost per meal
Set the purchase price to zero for the running cost alone.
Questions
What is the cheapest way to treat a fence?
On these prices, a one coat treatment redone when it fades, at 16.7p per square metre per year. It needs recoating more often, but goes on in one coat rather than two and costs much less per litre.
Is five year fence paint worth it?
On cost, no. It works out at 29.7p per square metre per year against 16.7p for a one coat product, because it needs two coats and covers less per litre. What it buys is fewer days spent painting the fence.
How much does it cost to treat a fence?
For one face of about 20 square metres, between £33.33 and £68.57 over ten years in materials. Treating both faces doubles it.
Should I use garden paint on a fence?
It is the dearest option here at 34.3p per square metre per year, and its coverage figure is not for rough sawn timber, so on a fence it does worse. It earns its price on gates, sheds and furniture, where the area is small and the colour matters.
How do I compare fence treatments properly?
Divide the tin price by its litres, then by the coverage per coat, multiply by the number of coats, and divide by the years it claims to last. That gives a cost per square metre per year, the only figure that compares a two year product with a six year one.
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More garden and diy costs, or read how we work these out.
Prices used on this page
- Electricity, 26.32p per kWh. Ofgem price cap, direct debit, average of England, Scotland and Wales, including 5% VAT.. Ofgem energy price cap unit rates and standing charges. Checked 1 October 2026.