If you want privacy from a wooden fence, it is a good idea to to overlap the fencing boards to compensate for the natural contraction of the wood. A fence with boards placed closely together might look solid when it is new, but as the wood ages, the gaps open and become easy to see through. You can counteract this by hanging boards on both sides of the rails. Overlapping all the boards about one-third of the board's width is cheaper than butting them, but it will be more expensive on a two-layer fence. It will, however, remain peep-proof.
Mark the perimeter of the fence. Dig holes in the corners and at 2.4 metre (8-foot) intervals between the corners, spacing the gate posts by 75 to 90 cm (30 to 36 inches). The depth of the holes should be one-third of their above-ground height.
Set the posts in the holes, and backfill with concrete mix, using a level to make sure each post is plumb while you add concrete. The height of each post should be 2.10 metres (7 feet). Let the concrete set.
Install the top rail on the tops of the posts. Cut the 5 by 10 cm (2-by-4 inch ) rails with a circular saw so they join at the midpoints of the posts, and screw them in with 7.5 cm (3-inch) nails. On sloped ground, you will have to tier the fence, so start installing the rail on the top of the post at the lowest point, then attach it to the next post on higher ground at the point where the rail is level. Install the next rail on the top of that post and proceed uphill, installing rails in the same way.
Install the bottom rails between the posts, cutting them with a circular saw so they fit snugly between the posts. The bottom rail should be 20 to 30 cm (8 to 12 inches) above the ground. If the ground is sloped, tier the bottom rail in the same way as you did the top rail in Step 3.
Use screws to attach 2.4 (8-foot) fencing boards on the most visible side of the rails, making sure the first one is flush with one side of the gate entrance and trimming the last one to be flush with the other side. Use a level to make sure each board is straight, and allow a gap between the boards that is one-third of the board width. Use two 4.10 cm (1 5/8-inch) screws in each of the top and bottom rails. The boards should be as close to the ground as possible without touching. They will extend about 30 cm (12 inches) over the top railing.
Use screws to attach fencing boards onto the other side of the rail, with the same gap, and position the boards so they are in the middle of the gaps between the boards on the other side.
Cut two pieces of 5 by 10 cm (2-by-4 inch) railing to fit in the gate entrance.
Set these rails on a flat surface so their spacing is the same as the spacing between the top and bottom rails of the fence. Join them by screwing on two fencing boards so the ends of the rails are flush with the edges of the fencing boards. Add a 5 by 10 cm (2-by-4 inch) brace that extends from one end of the top rail to the diagonal end of the bottom rail.
Add fencing boards to the front and back of the gate in the same pattern as the fence.
Hang the gate, then install a latch, lock and/or deadbolt.
For extra privacy, make the gap between the fencing boards smaller if your budget allows. On steep ground, consider using longer posts and fence boards so you can follow the ground contour and still keep the fence to 2.4 metres (8 feet) at the high point of each tier. The best wood choices for exterior fences are cedar and redwood.
This type of fence is heavy and can be displaced by a strong wind if the posts are not set deep enough in the ground. Pounding nails about halfway into the bottoms of the posts before you pour concrete will increase their stability after the protruding nails become embedded in concrete. Wear safety goggles when using a circular saw, and keep your hands out of the path of the blade.