The best wood fences are made of naturally rot-resistant and pest-resistant lumber. Although many home improvement stores consistently offer inexpensive fir and hemlock fence boards, the higher initial cost of a more durable species pays off in both appearance and longevity. The principle of "you get what you pay for" applies to fence rails and posts as well. If boards, rails and posts are made of high-quality lumber, your fence will perform at its best.
Home improvement warehouses often offer redwood fence boards as the premium fencing option. The attractive natural hues of the redwood's flesh range from whitish-pink to a rich brown-red. Additionally, heart redwood contains substantial amounts of tannic acid, a naturally occurring compound that provides the tree with near immunity to rot and pest damage. Only heart redwood contains relevant amounts of tannic acid. The term "heartwood" refers to the hard, innermost flesh of a tree, as opposed to the young, outermost "sapwood." These terms apply to all tree species, not just redwood. Redwood's heartwood is a deep red colour. If you purchase redwood posts, rails or boards for fencing, ensure that the lumber is "all heart." Although all-heart redwood is expensive, redwood that contains excessive sapwood offers no advantage to the builder.
Like redwood, cedar brings both natural beauty and durability to a fencing project. Although building material suppliers market several species of cedar for outdoor building projects, many builders consider western red cedar the premier species for its deep clay-red hues and natural durability. Naturally occurring compounds called tropolones provide cedar species with rot resistance and pest resistance. Significant tropolone content occurs only in the heartwood portion of the cedar tree. Due to a relative abundance of supply, all-heart cedar is generally less expensive than all-heart redwood.
Typically reserved for interior, finish-grade projects, hardwoods are exceptionally attractive and equally costly. The hardwoods suitable for exterior building projects, such as fencing, are the same hardwoods used for shipbuilding and outdoor furniture building. Although most mahogany species appear prohibitively expensive, builders often use them judiciously, only for exposed features, such gates and decorative accents. Alternatively, the rot resistance and pest resistance of the tropical hardwoods often matches that of redwood, cedar or mahogany. Tropical hardwoods, such as ironwood, are generally less expensive than traditional hardwoods, such as mahogany.
Regardless of wood species, careful construction practices can substantially increase a wood fence's lifespan. Many fence builders simply sink fence posts into post holes. Regardless of lumber grade or species, below-grade lumber deteriorates faster than above-grade lumber. Therefore, raised post brackets are the preferred method of fence post installation. To improve the longevity of the overall fence structure, fencing fasteners, such as nails and screws, must be corrosion-resistant. Corrosion-resistant fasteners include galvanised fasteners and stainless steel fasteners.
- University of Minnesota: Sustainable Urban Landscape Information Series -- Selecting Wood for Outdoor Structures
- University of Tennesse Extension: Decking Lumber Options; Adam M. Taylor
- University of Massachusetts Amherst: Wood Myths -- Facts and Fiction about Wood; Paul Fisette; 2005
- Michigan Technological University: Non-Resin Canal Softwoods