Timber fencing seems like an easy decision. Garden enclosed, job done. But after a few years, the posts rot and soften, and the fence starts leaning. The south facing panels turn gray, and the shaded panels turn black and develop algae. All of this can easily be avoided and isn’t worth the new fence costs. It is not uncommon, however, to face all of this due to poor decisions rushed at the point of purchase.
Understand the Fence Posts
The one thing worth understanding about fences is that the posts determine how long the fence lasts. The panels can easily be replaced, but the posts once set, are the skeleton of the fence, and will eventually fail the entire system if specified poorly.
As a minimum standard, fence posts should be softwood lumber treated to UC4 standard for in-ground use. UC4 standard is the ground contact hazard class of timber, meaning that the treatment has been applied under pressure and will be genuinely resistant to fail when the timber is in-ground. If timber fence posts are sold as “treated” without this standard, they may have been dip-treated, or surface-treated, and will quickly fail when in-ground and wet.
Concrete spurs are good for areas with high winds or exposed sites. spurs are sunk in the ground and the timber posts are bolted to the spurs at ground level. With this system the timber posts are kept out of the moisture. Spurs are more expensive and more industrial looking than some other timber posts. Some spurred fences have been standing for years while adjacent fences are falling.
Post depths that get cut short are common. A post should be a third of its overall length in the ground. a 1.8m fence should have a post of 2.4m, 600mm in the ground. Seeing as costs always seem to be an issue, planting a 2.1m post to the same depth is common. This results in undersupported fences that ultimately do not stand up in the face of wind.
Additionally, to the fencing options, is the variety of infills.
Featherboard is popular for residential fencing and for good reason. Featherboard infills are made using louvred construction. Because of this design, featherboard infills shed water and have small movements in the boards without compromising the structure. Featherboard infills are not the most rigid, especially when compared to a solid infill panel. Because of this, they flex in winds and put pressure more stress on the posts.
Closeboard fencing consists of individual timber pales that are laboriously secured to arris rails. Though it takes longer to install, it is far more durable. Unlike a fencing panel system, where the entire system must be uprooted to replace an individual board, the closeboard system allows for the replacement of an individual board without disruption to surrounding boards. The arris rails will need to be periodically checked, as they are housed in mortices in the post and are a common place for moisture to enter.
The more recent design trends favor a more minimalist style in the garden, with fencing incorporating a more modern aesthetic of timber boards arranged horizontally with gaps in between. Since contemporary fencing design favors slatted wood, a closeboard fencing system would be a poor choice in these situations and for obvious reasons (like keeping animals out).
The choice of a gravel board at the panel base elevates the fencing system as a whole by preventing the base timber from absorbing moisture from the ground, preserving its structural integrity. It is a small cost to extend the life of a panel and prevents further costs associated with fencing system replacement.
Roof felt capping is a fence building classic that should be here to stay. Fence posts are engineered wood and essentially have a top end grain exposed to the elements. Simple felt easily and affordably caps the end grain and reduces moisture at a critical junction. Factory machined angled end caps are designed to shed water and will cover the end grain of a fence post, but only if the angle of the end cap is steep enough.
There is the yearly debate of capping posts and staining or oiling. Untreated, pressure-treated softwood panels will turn silver-grey, but will not begin to rot, yet will still degrade and check. Fence staining, every two or three years, will slow checking and improve the overall look of the fence. Water based staining products are easier to apply and have more improved formulations than previous oil based staining products.
The Neighbour Question and Boundaries
Misunderstanding the ownership of boundaries is common. The title deeds or register will have a specification of which boundaries belong to which property, and that is the document to check. Whereas, if the boundary is not specified, it is a subject of agreement rather than assumption.
You typically don’t need planning permission for garden fences that are two meters high adjacent to a garden, or one meter high where the boundary meets the highway. Extra restrictions may apply for conservation areas and the grounds of a listed building, and may be worth checking before you install the fence, as opposed to after.
What to Consider Before the Contractor Arrives
What post treatment will be used, and will concrete spur or direct burial be used, as well as the depth of the post, inclusion of a gravel board, and what will be done with the existing fence while the new one is being installed, i.e. will it remain standing while the new one is built, or will it be taken down to leave the garden open? Having these questions answered before the fence is built is the difference between a straightforward job and a contentious one.