Building a fence that follows the ups and downs of your property often depends on choosing the right style of fence for your land and modifying the design as necessary. A post-and-rail or post-and-board fence (page 196) conforms to any terrain and is best for sharply sloping or rolling ground; a fence with vertical members face-nailed to a post-and-board frame follows the ground almost as well.
On rough but relatively level ground, a fence with pickets or slats (page 206) can smooth out small dips and rises; its bottom follows the earth’s contours while the top remains level. For such a fence, buy enough long pickets to fill in the low spots.
Rectangular-paneled fences are not suited for rough or rolling ground, but they adapt well to steady slopes if built in steps (page 207). Uniform stepping requires a few calculations, but once the posts are in position, attaching stringers and siding is straightforward.
Normally, the top of each fence section is set level. But on a steep hill this can create the illusion that the section is actually higher on the downhill end. In this case, some fence builders lower the downhill end of the stringer 1 or 2 inches below level until it looks right.
Wear safety goggles when hammering.
Going up and down hills
Set posts on each rise and in each depression, then space the remaining posts between them. For a post-and-board fence like the one shown, clamp or tack the boards in position against the posts and use a level to make vertical marks on the boards at the post centers wherever two boards meet (above). Trim the boards at the marked angles. Before attaching vertical slats or pickets, align them evenly above the top stringer with a spacer (page 196) then plumb each one.
Leveling bumps and dips
Make a spacer as shown on page 200. To line up pickets on uneven ground, hold each one upside down against the stringers with its shaped top ½ inches off the ground. Mark its bottom end even with the top of the spacer (left), then trim to the mark. Install the pickets as you would for a standard picket fence (page 200).
While a picket fence does not have to follow the exact profile of the ground, incorporating this feature is a nice professional touch. Simply trim the pickets to length using the method shown above, but let the pickets touch the ground. Place them in position against the fence, right-side up. Hold a carpenter’s pencil on a short piece of scrap 2-by-4 (right). Slide the block along the ground to scribe any variation in the terrain on the bottom of the picket. Trim the picket with a saber saw. The gap between the pickets and the ground will be uniform all along the fence.
Stepping down a slope
Run a level line from the top of the hill to a tall stake at the bottom (page 191). The height of the line on the bottom stake is the hill’s vertical drop. Lay out the fence line and mark the post locations as shown on page 191. Divide the number of fence sections into the total vertical drop to calculate the “stringer drop” from one section to the next. Set the first post at the top of the hill to the intended fence height, and the rest of the posts to the fence height plus the stringer drop. Mark the stringer drops on the posts, then attach the stringers (page 199). For a fence with vertical boards, trim each one so its bottom conforms to the slope, the top is even with the top stringer, and there is a 1½-inch gap between the board and the ground (left).