The Right Materials

Typically a woodworker will choose from among three materials when building a gate – a naturally decay resistant wood, a pressure treated wood, or a composite wood. For a classic gate choose a domestic decay resistant wood like redwood, western red or eastern white cedar and white oak, or one of the popular exotic species – ipe, meranti, mahogany or teak.

Pressure treated (PT) lumber is an economic alternative to decay resistant wood, though at the cost of appearance, and the presence of chemicals that do leach into the soil. PT lumber used for residential applications no longer contains Chromated Copper Arsenate, which was suspected of leaching arsenic into the soil. Today’s PT lumber is treated with a solution of chromate and other chemicals, including Alkaline Copper Quat, Sodium Borate and Zinc Borate, along with fungicides and insecticides. As long as it’s not used in or near vegetable gardens, PT lumber is a reasonable choice for gates or fencing. It can also be painted or stained, though you have to ensure it is dry before doing so.

Composite wood, such as the Trex brand (trex.com) consists of recycled wood and plastic, and has become a popular choice for decks and fencing because of its perceived low-maintenance and long-life characteristics. Bear in mind that composite wood can’t be re-finished like real wood, it is subject to colour fading, and it lacks the strength for large structural members such as gate posts. While hollow composite posts are available, neither should they be used for gate posts; they won’t support the weight of the gate doors. You won’t have to bother with applying or maintaining a finish, but you will have to regularly clean the product, paying special attention to mold growth.

For lasting results, use sturdy heavy duty latches and hinges that are galvanized or enamel coated (stanleyhardware.com). Gates can weigh quite a bit, and a set of poorly made hinges won’t stand up to the stress of constant opening and closing.

Design Variations

The simplest gate is essentially a board and batten construction; two horizontal boards connected by a diagonal brace, on which vertical battens are attached by deck or stainless steel screws or galvanized nails. A similar, and somewhat more robust version consists of a frame, often made of 2 x 2s or 2 x 3s, nailed or screwed together. A diagonal brace helps to keep the frame from sagging. The classic version is a framed gate made with mortise and tenon joinery – strong, sturdy and handsome.

A mortise and tenon gate made from a decay resistant wood makes a statement about your home, and your woodworking skills. A typical M&T gate will be constructed on 2 x 6 stock for the framing, and ¾” stock for the battens. As an option you can peg the M&T joints. Cutting the mortises by hand with mallet and chisels is not overly difficult. You’ll save time by removing the waste with a Forstner or saw tooth bit and drill press. Aim to keep the sides of the mortises plumb and square. The trick is to use sharp chisels and take thin cuts; no need to rush things. You can cut the tenons with a handsaw, but I prefer using a tenoning jig on the table saw. Make the tenons a tad larger than the mortises, and then fit them precisely during assembly. Remember to use a waterproof glue like Elmer’s E741 when assembling the gate (elmers.com). Leave at least a ½” clearance for the latch and hinge, and two to four inches clearance above ground.

The two key areas where you can really express your creativity in gate design are the top stiles and the battens. Some common shapes for the top stiles are flat, arched, concave (reverse arched) and cathedral. Likewise, you can arrange the battens in a wide variety of configurations, or even replace them with metal lattice or other materials.

A Solid Foundation

The success of your gate will be directly related to how good a job you do installing the gate posts. Strong, rigid and plumb gate posts will result in gates that swing open easily and close securely, year after year. Dig the post holes to the frost line, cover the bottom of the holes with crushed rock (to facilitate drainage), install the posts plumb, and pour concrete to hold the posts in place. As an alternative you can install a concrete pier. Place a sonotube (a tubular cardboard form) into the post hole, brace the tube so that it’s plumb, fill the tube with concrete, and insert a galvanized post anchor into the top of the concrete filled tube. Ensure that the concrete has fully cured before you install the post on the anchor.

For a light gate (one made of ¾” stock) you can use 4″ x 4″ posts; however for a heavy gate, or a double gate, it’s a good idea to go with 6″ x 6″ or larger posts. Gate posts can be free standing or they can be bridged to provide extra support against racking, ensuring that the gate doesn’t bind. You’ll need longer posts on a bridged gate, as the bridge (header piece) will need to be above average head level (at least 6′ 8″). A bridged gate is often incorporated into an arbour and trellis. While you can use galvanized framing plates to hold the bridge onto the posts, mortise and tenon joinery will give a cleaner, more professional look.

The Right Finish

Unless you select a composite material for your gate, it makes sense to apply some kind of finish. Harsh winter conditions; sun, heat and rain, all contribute to the degradation of the finish over time. However, it is moisture and UV radiation that are the two major factors that contribute to wood degradation. An annual inspection of the gate and prompt attention to any deteriorating sections of the finish is a good habit to get into.

Select a finish that is easy to maintain, repels water and has ultra violet (UV) inhibitors. Remember that the gate will be subject to continuous seasonal shrinking and swelling as moisture levels change. As a consequence, a finish that forms a film when it cures has the possibility of cracking and peeling, particularly if the surfaces are likely to receive a lot of use (or abuse). It’s imperative that the surface be completely dry and quite smooth before applying a film finish. A popular film finish is Circa 1850’s Exterior Varnish (circa1850.com).

A penetrating finish is absorbed more readily into wood pores (particularly on end grain) and is very easy to apply. Popular finishes for gates and other outdoor wood products include Cetol (sikkens.com), Penofin (penofin.com) and Flood (flood.com). These products are available as clear and coloured stains. For an ecofriendly product consider the Canadian product Lifetime Wood Treatment (valhalco.com). Penetrating finishes can be easily applied with a brush; many can be sprayed on, and touch-up of deteriorating surfaces is quick and easy.

If you do intend to paint the gate, then choose a premium outdoor paint, like Rust-Oleum’s Premium Door Paint (rustoleum.com). This oil-based paint has good chip and fade resistance, and dries fast. It’s critical that your wood is dry before applying paint, as any moisture will be trapped under the cured paint surface. You should expect to get from six to eight years before having to repaint.

RESOURCES

“Building Outdoor Structures”,
Scott McBride, Taunton Press, 2007, ISBN: 1561589395

“How to Build Wooden Gates and Picket Fences: 100 Classic Designs”,
Kevin Geist, Fox Chapel, 1994, ISBN: 0811730068