Fence boards are consistently exposed to tough weather conditions and are often constructed improperly, promoting splitting and warping. Splitting occurs with improper usage of nails for construction. The wood of the fence naturally shrinks and expands, causing the boards to warp. Knowledge of how to properly put together a fence and protect it against the elements will prolong the life of your fence.
Buy the correct materials for fence construction. Pressure-treated wood is often used because it does not rot as easily, even when in contact with the ground. Also buy blunt-tipped nails as opposed to pointed nails to reduce splitting when nailing into the wood.
Construct the fence properly. Pre-drill holes before nailing the fence together and do not over-drive the nails into the fence. This will prevent splitting. Install backrails on the fence no more than 8 inches from the top and bottom of the fence to prevent warping. For fences taller than 6 feet, install another backrail in the middle. At 8 feet, two backrails should be installed in the middle to further prevent warping.
Apply a sealant to your wood. A product specializing in preventing warping and splitting will slow the drying process of the wood and thus slow any expanding or shrinking that might occur. Reapply the sealant when it is no longer effective, which may be indicated on the package or by the manufacturer if you ask them.