Tutorial: How to build a Deck
6. DECK RAILING
The rail system is important because it’s the first thing your guests will see. It’s got to be cool, hip, groovy, far out, spiffy, fly, the cat’s meow, depending on your generation, pick an adjective. There are four basic component parts. They are the posts (aka newels), top rail (aka cap rail), bottom rail (aka shoe rail) and balusters (aka spindles). One method of installing posts is just to extend the deck support posts up above the deck. Check the code requirements in your area but the top rail is usually 36” to 42” above the deck at a minimum. Add this measurement to the length of the support post used and remember that lumber is sold in even number increments, then cut the post to the appropriate height. Another way is to do the posts as a separate piece of the deck. The sloped rail on the stairs is called a rake rail. Stair rail posts should be every 4’0” max, while the deck posts may be up to 8’0” apart. The spacing of the spindles should be too slim to slip through (good alliteration, huh?). They are measured from center to center not the gap between them. This measurement should be 4”. This also applies to the spacing from the shoe rail to the deck. This spacing should be about 3” to 3 1/2”.
Using the second method, start by identifying the location of each newel post. Make sure there is a newel at each corner of your deck and on either side of the stairs. At the bottom of each post, cut out a notch about 1/3 to 1/2 the thickness of the post and six to ten inches tall. This post will fit over the edge of the deck, then down the front and sides. You can either nail it or bolt it to the header. First, figure out the thickness of all the wood, then use a nail 1/2” smaller or add 1” for the appropriate length of a bolt. Just make sure it is secure because people will be leaning against it. Your next choice will be whether to run the cap rail continuously over the posts or butt the railing into each post. You can readily buy pressure-treated railing parts and pieces. You can also make a railing by using a 2x4 on top of a 2x6. This is quick, easy and adequate. Miter (cutting lumber at a precise angle) the corners to a 45° angle and nail straight down into the top of each post. Beveled balusters can be bought at better lumberyards. They will be plain and smooth with slightly rounded edges (eased) and either 36” or 42” in length. Nail them to the outside edge of the 2x6 and the deck header. The deck posts are 8’0” on center. The rail sections you’ll be making must be smaller. The posts are 4x4’s (3 1/2 x 3 1/2).
Therefore the distance between them is 8’0” minus 3 1/2”. Where does this 3 1/2 come from? It represents half a post from each end. (1 3/4 + 1 3/4). So the gap between posts, and each of your rail sections, is 7’ 8 1/2”. If you posts happen to be closer together, you still need to subtract the 3 1/2”. Cut your top and bottom rail (if you are using one) to size, connect the balusters, then toenail both ends of the top rail and do the same for the bottom rail. There are rail patterns where the balusters are nailed right to the deck or the header eliminating the shoe rail. Do whatever appeals to you.
The readymade railing is nicer looking and is available in several styles. Go back to your local lumberyard and have them order it for you if that’s the direction you want to go. The prettier rail patterns are also more complicated to put together. Follow the included directions. All the parts and pieces are readymade to fit together saving you the aggravation. The readymade railing may have to be assembled in sections, by you, and then nailed in place between the posts. Nail the spindles to the shoe rail first, then the cap rail. Remember the spindle spacing is measured center to center and not the gap between. You will only need one nail accurately driven into the center of the spindle at the bottom end. You’ll see that both the top and bottom rails are grooved to accept the spindles and to keep them from twisting. If you don’t want the nail visible from the top, then you musttoenail them from underneath. Using two nails drive them at an angle through the baluster into the underside of the top rail. The nails will be on opposite sides of each spindle near the top. A 6d galvanized finish nail will probably be adequate. One last piece of business is to fill in the gaps between each baluster. This is optional. You may or may not find it to be ascetically pleasing. This involves cutting to length a small piece of wood specially made to fit in the groove in both the top and bottom rails. This wood is called a fillet. Tack this in place with 1” brads and glue it using any wood glue. After each rail section is completed, toenail each end into the posts both top and bottom. Of course the railing must be level and to accomplish this task, precut two or three 4x4 blocks to the appropriate height, then rest each rail section on these blocks so you may nail the sections in place. The last thing to do is finish off each post with some type of top covering. There are many different kinds and types of post covers, both wood and metal. The cut end of any piece of wood is the most vulnerable to the elements and Nature (weather and bugs). If you have no plans for a stair, then this completes your task and adventure. Take a moment to gaze upon the wonder of nature and how you have affected a profound change upon her. To build a stair, one must continue to read.