Why wood needs particular care
Wood is a popular fence material because it is easy to work with, widely available and adaptable in style. It is also a natural material that absorbs moisture, moves with the seasons and can decay or be attacked by insects. Most of the best practices in wood fence building are about keeping water out of the places where it does harm and keeping the structure stiff as the wood moves. This guide covers the build details that are specific to wood. For the general sequence, see the other installation guides on this site.
Wood species, treatment and grading vary by region, and so do rules and conventions. Check what is sold locally and follow the supplier’s and manufacturer’s guidance.
Choosing and preparing the wood
Posts that go in the ground should be rated for ground contact. Untreated wood in soil can rot in a surprisingly short time. Rails and pickets above ground have less demanding requirements, though they still need to resist weather. Some woods naturally resist decay better than others, and our piece on wood species choices helps with comparing them. Treated lumber works well but has handling requirements, so use gloves and a mask when cutting and follow disposal guidance.
When wood arrives, store it flat, off the ground and under cover, with spacers between stacks so air circulates. Lumber left in a damp pile can warp before it is installed. Let wet wood dry to the degree the finish manufacturer recommends before sealing, as some products need dry wood.
Posts and spacing
Post spacing for wood fences is commonly in the range of six to eight feet, but the right figure depends on the rail size, the fence height and the load on the fence. A solid, tall fence is under more wind load than a short picket fence, so posts may need to be closer together or larger. Our piece on wind load discusses why.
Set posts to a depth suited to their height and local ground conditions, as covered under post depth. Footing material, whether concrete or gravel, affects how long the wood stays dry at the base, and the guide to post footings explains the differences. A common detail is to shape the top of a concrete footing so water runs away from the post, and to avoid sealing wet wood in a way that traps moisture.
For the tops of posts, cut a slope or add a cap. End grain absorbs water quickly, and an exposed flat top is a common starting point for rot.
Rails
Rails run between or across posts and carry the weight of the pickets or boards. Two rails are common on shorter fences, and three on taller ones, though the specifics depend on height and design. Rails can be mounted on the face of the posts, inset between them, or set in notched joints. Face-mounting is simplest, while inset rails can give a neater look but need careful joinery.
Rails should be sized for the span. Long spans of thin rail will sag. Use brackets or screws that suit the load, and check that the connection to the post is solid. Where rails meet posts, water can collect, so angle surfaces where practical, or leave small gaps for drainage.
Attaching pickets and boards
Whether you use pickets, vertical boards or horizontal slats, consistent spacing matters for both appearance and structure. Use a spacer block between each piece rather than measuring each one. Keep the bottom edge a small distance above the ground, as wood sitting on soil takes in moisture and can rot. The discussion of picket spacing explains how gaps affect airflow and appearance, and wood movement is the reason gaps are usually left even when boards look tight at installation.
Start from a plumb first board, check level regularly and avoid forcing warped pieces. If a board is badly bowed, set it aside for cutting into shorter pieces. Boards should be fastened with at least two fasteners at each rail, placed to avoid splitting near the ends and edges. Pre-drilling can help with hardwoods and with fasteners close to an edge.
For a double-layer design, such as a shadowbox arrangement, the way boards overlap affects how the wood moves, as the article on board-on-board and shadowbox fences compared explains.
Fasteners
Fasteners are small but important. Choose types made for outdoor use, and make sure they are compatible with your lumber. Some treated lumber can corrode plain steel fasteners, and certain woods can stain around them. Hot-dip galvanized or stainless fasteners are widely used for those reasons, but check the lumber and fastener manufacturers’ recommendations. Screws generally hold better than nails and are easier to remove, while nails are faster to install. The overview of fence fasteners looks at the tradeoffs.
Gates in a wood fence
A wood gate is heavier than the same panel of fence and moves constantly, so it needs sturdy posts, a rigid frame with a diagonal brace, and good hinges. Without these, it will sag. Read about gate bracing and gate hinge types before building or buying.
Sealing and finishing
Finishing slows moisture changes and protects against sun and mold. Options include clear sealers, semi-transparent stains and paint, each with different upkeep patterns. Apply finish to all faces and to cut ends, where possible, before assembly or soon after. Follow the label for conditions, drying time and coverage.
Plan to refinish periodically. The schedule depends on climate, exposure and the product, so check the fence each year. Our pieces on fence staining and painting fences describe the steps, and regular care of this kind often does more for a wood fence’s lifespan than the choice of wood alone.