Having a wood dock or pier is a nice addition to lakeside property, but the wind, waves and sun can take a big toll on the condition of the deck through the years. Sooner or later, the deck will become unsteady or even dangerous and will require extensive repairs. Removing and replacing the deck boards can be both costly and labor-intensive. However, a simpler and less-expensive way to fix a worn-out deck is to install a new deck on top of the older wood. Below is how you can build one yourself:
Tools and materials needed
1x6 cedar boards - see below for information on calculating the length needed
⅜-inch diameter stainless steel lag bolts, 6-inch lengths
Number 8 stainless steel wood screws, 3-inch lengths
Cordless drill with screwdriver bits
Circular saw or cut-off saw
Orbital sander with medium-grit sanding discs
1. Determine how many feet of cedar boards are needed - before beginning, you will need to determine how many feet of boards are needed to complete the deck. There are two components for which you need to calculate lengths: lengthwise supports and cross pieces. Here is how to measure and make the necessary calculations:
Lengthwise supports - the new deck structure will require that you construct three lengthwise supports to run from one end of the dock or pier to the opposite end. To calculate the number of feet needed, measure the total length of the dock or pier and multiply the measurement times three. For example, if your pier is 50 feet in length, you will need to purchase 150 feet of 1x6 cedar boards to use for building the lengthwise supports.
Cross pieces - determining the amount of cedar boards for use with the cross pieces requires knowing the length of the pier as well as its width. Based on the instructions below in step 3, you will need to lay two 1x6 cedar board cross pieces for every linear foot of pier. Using the example above, that means a 50-foot long pier will require 100 cross pieces. Next, multiply the number of cross pieces times the width of the pier deck. If the hypothetical 50-foot pier above is 4 feet in width, then that requires purchasing a total of 200 feet (50 times 4) of 1x6 cedar boards for the deck cross pieces.
2. Install the lengthwise supports - after obtaining the necessary 1x6 cedar boards, begin by laying a lengthwise strip of 1x6 boards on top of both edges of the existing deck structure. Attach the boards to the existing deck using ⅜-inch diameter, 6-inch long stainless steel lag bolts, but be sure to drive the lag bolts only into an underlying structure that is thick enough to contain the entire length of each bolt. Try to use one lag bolt per board for every two linear feet of pier, but fewer bolts are acceptable as long as the boards are held fast.
Once you have installed both lengthwise boards on top of both edges of the deck, install a parallel string of boards down the middle of the deck. After finishing, you will have three parallel, lengthwise strings of boards laid on top of the existing deck; these will serve as the support for your cross pieces.
3. Install the cross pieces - after installing the lengthwise supports, measure and cut a number of cross pieces equal to the number and length you calculated in step 1. Next, lay the cross pieces horizontally across the pier and attach them to the underlying lengthwise supports with #8, 3-inch long stainless steel wood screws. Separate each cross piece with three-quarter inch gaps.
Once the cross pieces are installed, use an orbital sander to sand-down the rough edges on the ends of each cross piece. In addition, take a careful look at the cross pieces and use the sander to remove any splinters you might find.
If you'd rather not do this work yourself, you can contact a local marine construction company like Abbott's Construction Services Inc. to help with repairing your dock's decking.