Installing Railings

Railings are intended to prevent falls, but this basic function doesn’t preclude the desire for a creative design. To the deck user, the decking surface may seem the most important and visible part of a deck. To neighbors and passersby, however, the railing is the most obvious feature. Legal code requirements dictate what constitutes a safe deck (see right). Beyond that there are an endless number of design choices and construction techniques.

The most common railings are similar to the traditional picket fence. A typical framework consists of 4x4 posts spanned by a 2x4 or 2x6 cap rail and a 2x4 bottom rail. Balusters attached to these rails provide the style. Another option is a completely enclosed railing. Faced with siding and open only at the bottom for drainage, it provides more privacy and blocks wind. To prevent sagging railings, keep the spans between posts less than 6 feet. The posts should be bolted to the frame of the deck; use two 7/16-inch bolts for each connection. Notched posts are the best-looking choice. Cut a notch 1 1/2 inches deep on the bottom of the post and about 8 inches long. Using this technique, you can use shorter bolts and the posts won’t protrude so much from the side of the deck. If your decking overhangs the edge of the deck, cut an opening for the post.

Tools: Circular saw, chisel, tape measure, pencil, hammer, power miter saw (optional).

1. Check your code. When a deck is 24 inches or more above ground, most building codes require a railing. Usually the railing must be between 36 and 42 inches high and must have balusters spaced close enough to prevent a 4- or 6-inch-diameter sphere from passing through them. (The sphere is intended to represent a child’s head.) Before you begin railing construction check with your local building department to review codes.

2. Calculate baluster spacing. Local building codes define the maximum gap between balusters. Getting evenly spaced balusters requires some math (numbers here refer to the above drawing). Add the width of a baluster to that of the maximum spacing and divide this figure into the total distance between posts [(60+(1.5+4)=10.9]. Round up the result to find the number of required balusters (11). Then to find the actual spacing between balusters, multiply the number of balusters by the width of one (11x1.5=16.5). Subtract that result from the total distance between posts (60-16.5=43.5). Divide the remainder by the number of spacings (always one more than the number of balusters) to determine the final spacing between balusters (43.5=12=3.625 or 3 5/8 inches).

3. Notch railing posts. Measure a distance equal to the joist depth, less Hindi, and mark the inside face. Use a circular saw or a tablesaw to make a series of closely spaced cuts 1 1/2 inches deep up to the line. Knock out the pieces with a hammer, then use a chisel to clean out the notch. Cut a 45-degree bevel on the bottom outside corner. If decking will overhang the deck, notch the decking for the post, leaving an 1/8-inch gap on each side of the post.

4. Install posts. Set the post on top of the decking, flush against the joist. Use a level to keep it plumb and drill two holes through the post and joist. Secure each post with 5-inch-long, 7/16-inch carriage bolts.

5. Cut balusters. Cut the balusters from 2x2 stock. Clamp four to six pieces together and cut them all at once with a circular saw. For a large number of repetitive cuts you may want to rent or buy a power miter saw. When cutting pieces with square and beveled ends, cut each baluster roughly to size with square ends. Then add a stop block (a simple jig fastened to the saw base) at the intended baluster length. Finish the baluster with the 45-degree bevel cut.

6. Install rails and balusters. Install 2x4 top and bottom rails equally spaced from the top of the post and the deck surface. Attach a 2x6 cap rail to the posts. Measure and mark a layout for the balusters or make a spacer as shown. Attach balusters with 8d nails.

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