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Wetland Trail Design and Construction

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Finishing Details

Although constructing the basic structure right is most important, often the mark of craftsmanship is most evident in the finishing details. Most of the following discussion applies to boardwalks. However, some finishing work can be used with other construction techniques.


Plank used for a deck often contains heartwood and sapwood. If the plank is placed with the heartwood face up, alternating moisture and drying-and the effects of freezing and thawing- will cause knots and some of the annual rings in the wood to lift. To reduce tripping hazards and future maintenance, deck plank should be placed "green side up" (the heart face down and the bark face up) (figure 55).

Image of decking
Figure 55-Place decking with the growth rings facing down to help prevent
cupping. Cupping causes the wood to rot faster and creates a tripping hazard.


A pedestrian railing system may be needed along the edge of a deck to prevent visitors from falling off. Various building and highway codes call these railing systems "handrails," "guardrails," or "railings." If you are planning to install a pedestrian railing, the details of the installation of the posts need to be thought out before placing the deck. Railing posts need to be sturdy. They are a potential liability. Flimsy railings installed as an afterthought are the ones most likely to fail. Usually, it is the connectors, not the railing, that fails.

The deck, posts, and handrail are all closely related in their construction. As a minimum, 4 by 6 timbers should be used to support handrails. Actually 4 by 4s that are surfaced on all four sides are only 3½ by 3½ inches. They make a flimsy post. The deck should extend beyond the stringers to the back of the post, or at least 4 inches. If this is not done, people standing on the deck and leaning on the railing will have their feet sticking out beyond the deck. (figure 56).

Image of handrail post construction
Figure 56-When the handrail post is attached to the stringer
below the deck, the decking should extend at least 4 inches beyond the stringer.

There are two ways to install railing posts. The most common requires the deck to be in place. The posts are toenailed to a deck plank. By itself, this is a weak connection and requires an angle brace for support. Therefore the plank supporting the post must extend beyond the edge of the rest of the deck. If the plank is too short, the angle brace will be too close to vertical to provide much support (figure 57).

Image of a handrail post attached to a long deck board
Figure 57-Attaching the handrail post directly to the
decking requires long deck pieces to support an angle brace.

The second method is to attach the posts to the outside of the stringers. It is much easier to bolt the post in place before attaching the adjacent deck plank. To provide solid support, 12 inches of post should contact the stringer. The posts can be accurately cut and drilled in a shop and brought to the site. To avoid the awkward and time-consuming work of notching the planks, the width of the post should match the width of the deck planking (figure 58).

Image of a handrail post attached to stringer
Figure 58-To provide proper support, at least
12 inches of the post needs to be in
contact with the stringer.

The top of each post or pile should be cut at an angle to shed water and to help prevent rot. To avoid a sharp corner at the top of the post, a narrow 1-inch area closest to the handrail should be cut level, and the sloping portion should be pitched away from the boardwalk (figure 59). For esthetic and safety reasons, the posts should not extend above the top of the handrail (figure 60).

Image of finishing top of post and a post below a handrail
Figures 59 and 60-Cut the top of the post at an angle, but leave
1-inch flat on the inside edge. The post should not extend above
the top of the handrail.

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Updated: 4/14/2014
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