In many instances, boat docks are built very similarly to traditional decks. They have the same weight distribution, along with the same beams, joists and decking. There are a few differences, however, to help account for the placement of the dock and the fact that a portion of it will be submerged. Once you’ve dealt with these particulars, it’s possible to build a boat dock that can complement any surrounding and serve functionally for years to come.
Just like with deck construction, before building a boat dock, it’s important to consider how it will be used. Not all docks are used just for anchoring a boat, so while it’s possible to simply build an 8-foot square and tie a boat to one pillar, it’s far more practical to consider all the possible uses and work them into the final plan.
Some considerations to make include:
Many states and areas do not regulate dock building and have no requirements. However, it’s still important to check with the local town or municipality before beginning construction, as some areas are protected and may require specific planning. While permits are not always needed for docks, it’s always a good idea to file plans anyway and to check for local ordinances before beginning.
While in many ways a dock is similar to a deck, it’s a fact that at least a portion of the dock will be submerged in water. Ideally, you want as much of the dock as possible above the water line, because anything submerged will be subject to harsher conditions and weathering patterns. However, you don’t want our dock located too high above the water as this will make it difficult to access your boat, among other activities like fishing and diving.
Therefore, plan on having the bottom of the docks beams a few inches above the maximum waterline. Remember that water levels can change and fluctuate over time, so when planning for the height of the dock, keep the highest possible level as your guide. For lakes, this is easy to find; locate the water runoff and measure its height. Runoffs are generally installed at the maximum height of the lake. For smaller bodies of water, you may want to check records or look at natural stone outcroppings to find the highest water mark and use it as your guide.
While it’s possible to simply sink wooden posts into the lake, pond, or ocean bed to create a dock footer, this isn’t necessarily the most stable or the longest lasting solution. In most cases, using a PVC pipe filled with concrete to surround the post makes the best footer. Either a 12-inch or 18-inch PVC pipe can be used to help support the dock, with the pipe extending several inches up out of the water so that any exposed wood will be kept from submerging.
It’s generally best to sink the pipe and concrete at least three feet into the bed; a post hole digger is usually enough to create a hole large enough to sink the pipe, which is then emptied of water before the post and concrete are added. In most cases, the posts will end up being 8 to 10-feet 6×6’s; they can be trimmed to height once the concrete sets.
Once the footers and outer posts have been set, you can start building the dock exactly the way you would build a deck. A frame is created first to the measurements and shape you determined, then decking material is applied. Shoreline support posts can be installed once the basic frame is complete; it’s necessary to wait until this point to install these posts as the frame can add stability, but also give better measurements than those taken from the outer posts.
Like a traditional deck, you have a lot of choices for the material used to cover the dock. Many people who have built with pressure treated wood in the past have been experimenting with other materials in more recent years due performance concerns. While pressure treated wood is often the most cost conservative dock planking option, it is prone to checking, warping and splitting, especially in an environment so exposed to moisture. In addition to the performance shortfalls, because docks are located directly above water, stain or paint that can peel, chip and flake can contaminate the water and is therefore often heavily regulated, which may affect the desired look you want. For these reasons and more, contractors and homeowners alike have been trending away from traditional pressure treated wood dock planking. Composite decking is often recommended for docks because of it’s superiority in moisture resistance compared to pressure treated wood, however it too has drawbacks to consider. Composite decking is primarily composed of plastic which causes it to heat up in the sun, making it difficult to walk barefoot on. It also has a very plastic look and feel to it, that many don’t like. Some more inexpensive versions also won’t hold up as well to the moisture levels of the area, which means only high-end composite materials should be considered. Another alternative is modified wood. Modified wood, like Kebony, is transformed from a natural softwood to a highly durable, water-resistant material that doesn’t require staining nor does it heat up in the sun. Because it’s real wood, it provides the rich, natural beauty that people look for and through the modification process it far surpasses pressure treated wood in performance and durability, to rival the best tropical hardwoods. Modified wood has truly cemented its position in the industry as an ideal material for boat docks.
Depending on the location, the number of boats you wish to moore and any other activities you plan on using your dock for, there are several different designs that may be suitable. Perhaps one of these dock design will help you decide what will work best for your project.
While many docks are fixed in their position using piling for support underneath the surface, others involve a flotation system that automatically adjust to high and low water levels. Floating systems can be used in both small, more private settings, but can also be scaled to equip an entire marina, like the one in this picture. This marina built a massive floating dock system, using natural modified wood decking, to make efficient use of the uneven shoreline and naturally adjust to different water conditions.