Why a picket fence still earns its place

A simple picket fence is one of the few boundaries that looks smart from both sides. It marks the edge of a front garden, frames a path, keeps a dog off the borders or separates a vegetable patch without blocking the light. Traditional softwood pales, properly spaced and finished, suit everything from a Victorian terrace to a modern new-build, and the materials are cheap enough that a manageable run of ten or twelve metres is a genuine weekend job.

Height matters. Around 900mm to 1.2m reads as a boundary rather than a barricade. If your fence sits on a front boundary beside a highway, anything over 1m generally needs planning permission, so it is worth a quick check with your local planning authority before you cut timber. Keep it below that threshold and you can usually crack on. A picket fence is also a good neighbour: it defines an edge without casting shade or feeling unfriendly.

Setting out the line before you dig

Every neat fence starts with a taut string line. Drive two pegs at the ends of the run, stretch a line between them, and check it is straight by eye along its length. If the ground slopes, keep the line level and let the pales follow the ground in steps rather than a wobbly diagonal.

Mark your post positions along the line. For a run of standard pales, posts at 1.8m centres work well; never go beyond 2.4m or the rails will sag. Use 100 x 100mm posts for the run, and step up to 150 x 150mm for corners and gate posts, which take far more load. Crucially, measure each post position from a single starting point rather than chaining from the last one, or small errors will accumulate and the final gap will look wrong.

Post holes, depth and getting things plumb

Dig holes around 600mm deep and 250mm wide — a post hole digger or auger saves a lot of effort. Drop 75mm of gravel in the bottom for drainage, then set the post so at least 450mm sits below ground. As a rule of thumb, a third of the post should be buried.

Get the first and last posts in and braced before you touch the rest. Check plumb in two directions with a spirit level, then hold each post with temporary battens screwed to the face. Mix concrete at roughly one part cement to four parts ballast, or use a post-mix compound and follow the bag. Leave the posts a full 24 hours before loading them. Saw the tops level or cut a shallow crown so rainwater runs off rather than sitting on the end grain — that single detail adds years to the life of the timber.

Fixing the rails level and true

Rails are usually 100 x 50mm, fixed flat to the face of the posts, or slotted into notches if you want a cleaner look. For a fence up to 1.2m, three rails is right: one about 150mm above ground, one in the middle, and one set just below the top of the posts, allowing the thickness of the pales.

Set a spacer block against the first post so every rail sits at exactly the same height, then level along its length with a spirit level before fixing. Two 75mm galvanised screws per joint are plenty, but pre-drill near the ends to stop the timber splitting. Work rail by rail, and check at each post. This is the stage where a fence either looks crisp or slightly drunk, so take the extra ten minutes.

Pales: even spacing and a straight top line

Cut and treat your pales first, then fix them from one end. Typical pales are 100mm wide with a 20–25mm gap — roughly a quarter of the pale width. Rather than measuring every time, cut an offcut to the exact gap and use it as a gauge. It is quicker and far more consistent.

• Run a taut line along the tops of the pales and keep each one just touching it.
• Fix two screws per rail, staggered slightly so they do not line up vertically.
• Leave a 25mm gap under the bottom edge so air moves and damp timber can dry.
• Pointed, dog-eared or flat tops all work — cut them before fixing, ideally with a simple jig.

Work in small batches of five or six pales, checking the top line and the gap as you go. Correcting a lean after twenty pales is far more annoying than catching it after five.

Treating, finishing and keeping it sharp

Brush preservative into every cut end — rails, pales and post tops — because that is where rot starts. Two coats of a good wood preserver or a coloured fence stain will see softwood through a decade of British weather, and it is far easier to do it flat on trestles before fixing. Reapply every couple of years to keep the colour even.

Once a year, walk the run and check for loose screws, movement in the posts and any pales that have weathered badly. Individual pales are simple to swap out, which is the quiet genius of this design. Build it level, space it evenly, and a plain picket fence will quietly do its job for years.