BUILDING A BOARDWALK- The Hand Rail
A pedestrian railing system may be needed along the edge of
a deck to prevent visitors from falling off. 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.
During floods, the posts and rails can catch debris and form
a dam. In most situations it is better to build as little as possible that will
have to resist the force of high-velocity floodwaters. A decision on how much
or how little to build should be based on the type and age of the visitors who
will use the finished facility-schoolchildren, senior citizens, day hikers, or
backpackers.
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.
The best 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.
If hard plastic or pliable plastic covers are not used on
the top exposed posts, they 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. For esthetic and safety reasons, the
posts should not extend above the top of the handrail.
Handrails for more remote trail bridges must be at least 42
inches high for pedestrian traffic and at least 54 inches high for bicycle or
equestrian traffic. These handrail systems must also have at least one
intermediate rail so that vertical distances between rails do not exceed 15
inches.
Not all wetland trail structures need railings. If the trail
itself has more hazardous drops than the trail bridge would have without a
handrail, a handrail is probably not required. Other considerations, such as
convenience, may justify installing a handrail. As a general rule, any fully
accessible trail with a drop of 4 feet or more should have a pedestrian railing
system.
All accessible trails should at least have a curb. A wheelchair
handrail is required for any accessible trail bridge on a grade of 5 percent or
steeper.
Install the railings after the posts and deck are complete.
Most railings consist of a top and bottom rail, usually 2 by 6s, although 3 by
6s make a better splice and a stronger rail. The stronger rail permits posts to
be spaced more widely than if 2 by 6s were used for rails. The rail can also be
cut and drilled in a shop where the splices can be cut accurately and more
efficiently.
Curb and bull rail are two names for the same thing. If the
drop from a boardwalk is about 30 inches or less, a curb is usually installed.
A curb is required for accessible trails. Curbs present a potential tripping
hazard for pedestrians.
Curbs placed directly on the surface of a wood deck can
cause the deck planking to rot. Leaves, needles, and dirt accumulate against
the curb, absorb water, and cause additional rot. During the winter, ice and
snow will build up on the deck, causing a hazardous condition. To keep the deck
from rotting, place the curbs on blocks. A finished block of 2 by 4 lumber is
only 1½ inches thick. Leaves and dirt can still build up against the curb and
under it. With just 1½ inches of space between the curb and the deck, it is
difficult to get a shovel under the curb, making this area almost impossible to
clean. A better solution is to use two blocks of 2 by 4 lumber, one on top of
the other, or one block of 4 by 4 lumber. The increased clearance under the
curb will not trap litter, and melting ice and snow will run off more quickly.
No comments:
Post a Comment