Because a gate with a double crossbar has extra bracing, it's less likely to sag over time. Traditionally, the diamond brace gate has five horizontal bars. One diagonal brace goes on the back of the gate and a diagonal brace going the opposite direction is on the front. The five-bar gate is heavier than most garden gates because of the double crossbar. To complete this project, you only need basic carpentry tools.
Measure the width of the gate opening. Subtract 1 inch to determine the width of the gate. Determine how tall you want the gate to be. Allow some room for clearance below the gate.
Cut five pieces of 1-by-4-inch lumber for the five bars of the gate, using a circular saw. Use a different size lumber if necessary.
Measure four pieces of the 1-by-4-inch lumber to the height you chose for the gate. Cut this wood with the circular saw.
Lay out the five horizontal pieces on a flat work surface. Lay two of the vertical boards on either end of the horizontal pieces to get them set at the right distance, top to bottom. Use a tape measure so each of the five boards is parallel to the ones above and below.
Drill two pilot holes through the vertical board into each of the horizontal boards. Repeat for the vertical board at the other end of the gate.
Slide the other set of vertical boards under the horizontal bars, taking care to keep the pilot holes aligned. Align the bottom set of vertical boards with the top set of vertical boards. Attach all three layers of boards together with galvanised screws. The screws should be long enough to go into the third layer of wood but not all the way through.
Lay a piece of 1-by-4-inch lumber diagonally across one side of the gate. Place it so the ends come to the inside edge of each vertical board and align with the top and bottom edges of the horizontal boards. Mark where you need to cut to get the angle so it fits, then cut the board. Make an identical board for the opposite diagonal.
Place the diagonal brace pieces so one piece is on the underside of the gate as it's lying on your worktable. Put the other brace on the top of the gate going the opposite direction. Pre-drill two holes in each place where two pieces of wood overlap. Don't drill all the way through the wood.
Fasten the cross braces onto the horizontal pieces of wood, using galvanised screws. Use longer screws for the centre of the cross and shorter ones for the other connections. Do not allow the screws to penetrate to the front of the gate.
Attach one side of the gate hinge to the top and bottom of the gate, using the screws that come with the hinges. Hold the gate in place against the gatepost. Mark where to attach the other side of the gate hinge. Drill pilot holes in that spot.
Hold the gate back in place and attach the screws from the hinge assembly to the gatepost.
Mark where to install the gate latch and its catch on the gate and gatepost. Use the screws from the latch kit to attach the latch to the gate and gatepost.
It's not necessary to evenly space the horizontal boards. Spacing may be narrower between the lower boards and wider between the top. The boards do need to be parallel, however. If you are going to paint the gate, do so before you assemble the pieces. It's easier to entirely cover all the pieces of wood.