Which Fence Posts Last The Longest?

All timber products including fence posts are produced to last a number of years. Some posts may last just five years, while some are expected to last well over forty years. When undertaking your next fencing project it’s important to carefully consider how long you expect the posts to last for, as this will greatly impact your decision when choosing which lengths of timber to use.

The longevity of a post is determined by a number of factors. Firstly, the species of wood and where it was grown will play a role in its lifespan, as some woods are naturally more resilient than others. Secondly, the treatment applied to the timber and the method of application the treatment was applied with will also impact how long the posts will last for.

UC3 is a form of pressure treatment, whereby timber is placed into a vacuum chamber which evacuates the timber cells of air. The chamber is then flooded with preservative and pressure is applied to the chamber, forcing the preservative deep into the timber. UC4 timber treatment is much the same as UC3, except the timber is kiln dried before treatment to reduce the moisture content of the timber. This allows the preservative to penetrate deeper and thus considerably extends the life of the treated timber. UC4 timber is expected to last 10 to 20 years, compared to the 5 to 10 year expectancy of UC3 timber. HCD Incised timber is a more complex treatment that entails creating hundreds of small incisions along the length of the post, allowing the applied preservative treatment to penetrate deeper still than the treatment of UC4, ensuring an even greater lifespan.

Companies such as Octowood, the creators of the Octopost, are taking advantage of a combination of these factors to produce a unique octagonal machined post with a 25-year guarantee and life expectancy of between 30 and 40 years. Grown in close proximity to the Arctic Circle, the Swedish Redwood used for the Octopost grows incredibly slowly in this climate. The slow rate of growth allows for an extremely strong and resilient tree to be grown, giving the Octoposts a significant head start in terms of durability.

As most fence posts are in constant contact with the ground, this is more taxing on the timber, as the ground often retains more moisture and does not allow the opportunity for the timber to dry out as it would above ground. For this reason, the intended use of the post has a profound effect on the durability and longevity of the timber. It is important to choose timber with a treatment that is intended for below ground contact.

For more information about fencing and fence posts, speak to our expert team by calling us on 01625 861588 or visit our Chelford store to see just why we are a leading Cheshire timber merchant.