Building a deck yourself saves up to half the cost of a new deck, since you provide all the labour and materials. Putting it together in the proper order makes building the deck easier and smoother. There is more than one way to build a deck, however. When or how the railing posts are installed is one example of how deck building methods vary.
Local Building Codes
The overall decision for your railing post installation method and when it is done may lie with your local building code enforcement department. Railing posts may be considered part of the deck framing. If your building department requires a framing inspection, and many do, they may require you to install the railing posts when the deck is framed.
Posts Fastened Inside Joists
Post installation using this method takes place before any decking is laid. The posts are set against the rim joists at the corners and on the sides between the corners and bolted to the inside of the deck framing with 1/2-inch-thick galvanised or stainless steel carriage bolts.
This method offers a clean, finished look to the outside of the deck, since the posts do not protrude from the deck sides, but the decking is cut to accommodate posts. The posts and railings reduce the total usable area of the deck by about 1 square foot for each 4 feet of railing.
Posts Fastened Outside Joists
This method involves fastening the posts to the outside of the framing. The primary advantages of this method are that it may be done before or after the rest of the deck is built and it does not take up any of the usable deck space.
There are several minor disadvantages to this method. Two posts are required at the corners in order to accommodate a railing going along both sides, and the posts and railings protrude from the deck sides. If the decking extends past the rim joists, as is often the case, the decking will have to be notched to accommodate the posts.
The posts are set against the outside of the framing and bolted to the rim joists using 1/2-inch-thick stainless steel or galvanised steel carriage bolts.
Posts may be fastened directly to the decking with special deck railing post brackets that fasten onto the decking after it has been installed. The decking material must be strong enough to hold the bracket screws in place if a 200-pound personal falls against the railing. Some composite and plastic decking does not meet this requirement.
Not all building code enforcement departments have accepted the use of post-to-decking brackets. If you plan to use these, be sure to check with the code department before you purchase and include them in the plan you submit when you apply for your building permit.