Allow for Drainage in Building Fence : DOING IT YOURSELF

Americans, since the first settlers, have always been enthusiastic fence builders. Early fences contained livestock, while today’s fences are used to frame the lawn, define boundaries and provide privacy.

When you consider building a fence, pick a style that will fit its surroundings. Then measure the proposed perimeter to see how many sections you’ll need.

Most fences are built in six- or eight-foot sections. Posts are commonly 4x4s, although 6x6s and 8x8s are sometimes required for corners and gateposts. Rails, the horizontal bars, are 2x4s, and fence pickets or vertical boards may be 1x4s or 1x6s.

To prevent rust from staining the wood, use aluminum or hot-dipped, galvanized nails and hardware. Estimate the amount of gravel you’ll need for drainage. If you set the posts in concrete, figure that a 90-pound bag of premixed concrete occupies about two-thirds of a cubic foot.

Use wood that has been pressure treated with a preservative to resist rot and insects, or wood that resists decay naturally, such as cedar, redwood, cypress and locust.

Begin laying out the fence by locating the corner posts and driving in stakes. Then run mason’s twine tautly between two corner stakes. Mark the correct on-center position of each intermediate fence post on the twine with chalk. A plumb line against the mark centers each post on the ground. Drive a stake here.

In loose, sandy soil, it’s best to set posts in concrete--but only in frost-free areas or where the concrete will be below the frost line. Generally, set one-third of the post in the ground. Start with the corner posts.

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Whether you set a post in gravel or concrete, dig the hole four to six inches deeper than the post bottom for drainage material--a large flat stone or gravel bed. Flare the hole at the bottom for good support. Then stand the post in the hole on the drainage material.

To set the post in earth, fill in with six inches of gravel and tamp it solidly before replacing and tamping the excavated soil. Fill several inches at a time and tamp each layer.

Lay a level vertically on two sides of the post to make sure it’s plumb. Add a last layer of rocks at ground level and cap with a tamped-earth cone to drain water away from the post. In concrete, make the hole six inches deeper for gravel, set the post on the gravel and fill around it with concrete. Slope the top for drainage.

If posts are set in concrete, let them stand several days while the concrete sets; otherwise, add the rails immediately. Rails made of 2x4s are sturdy enough to hold most vertical fence boards. Thinner stock might bend.

Their ends can be toe-nailed, cleated or set with metal fasteners. Fence boards are generally one-inch stock, three inches or more wide. Most are face-nailed to the rails. For easy, even spacing, cut a board to the gap-width and insert it as a guide when nailing on face boards.

Gateposts are larger and deeper set than the rest of the fence to withstand the added stress. If the gate is to swing properly, it must be perfectly plumb. Allow for hinge and latch clearance when measuring. A diagonal brace to support the rails strengthens the gate section.