Building a Ground-Level Deck
Courtesy Fiberon Decking
Have you considered adding a deck to your outdoor space? While it may seem confusing or downright daunting at first, we are here to help with our handy guide to building an outdoor space. In this guide we will cover materials, planning, and building to help you confidently construct your brand new deck.
THIS IS NOT A COMPREHENSIVE DECK-BUILDING MANUAL! There have been entire books dedicated to the ins-and-outs of deck building. Consider this a primer, with lots of useful tips and also to get a sense of whether or not this is a project you really want to tackle!
Planning, Preparation, & Execution
Ground-level wood decks are typically not ground-level... they rest on (or slightly under) the ground and are a "step up". By constructing the frame from non-rotting pressure treated lumber, you don't have to worry about this deck ever needing repair due to mildew or fungus invasion!
And choosing a non-rotting, durable, prefinished decking material such as Fiberon composite decking will complete the circle, giving you a virtually maintenance-free deck (aside from occasional cleaning) with no chance of rot-related deterioration.
Lay out the deck
The first thing to do when constructing your deck is determine what size you would like it to be. For a simple rectangular ground-level deck, all you may need to visualize it is to lay out a string line with stakes to get the sense of the size. When measuring, keep in mind that the typical deck joist spacing is 16" O.C. (the distance between the centers of the tops of two adjacent joists). Less spacing will provide a firmer deck, though except in cases of anticipated extreme load it is a total waste of lumber!
Decide how you want to support your deck
Unlike raised decks on posts, supports can be very shallow. In fact, low decks do not need the type of deep foundations that are common for raised decks... up to 48" in areas prone to freezing. Shallow foundations do not "pop" or "frost heave" due to freezing the same way deep ones do and any slight movement will be uniform across all shallow posts. Be sure to get your local inspector's approval if necessary in your area... certain climates and soil types may need special consideration!
You can make your shallow foundation in a couple of ways. One way is to use preformed deck blocks. These blocks are dug in to the desired depth right into the ground without any need for a concrete base in most circumstances. My personal preference is to dig the holes an additional 6 inches and fill the holes with crushed gravel to the level needed. The gravel will allow water to drain away from the base of the blocks, further decreasing the chance of frost heaving, and also give you an easy way to adjust the level of each block to get the most even support.
Space the deck blocks at 4' to 6' intervals to offer the frame good support. I would not use a frame lighter than 2"x6" lumber. Using 2"x4"s will lead to a frame that is too springy and may sag under load, such as during those huge parties you will be planning... or a heavy winter snow load!
An alternative to deck blocks is to use rectangular patio blocks, laid underneath the corners of the deck and at 4' to 6' intervals directly on the ground. Though the deck blocks will give the deck more stability, if you are using 2"x8" or larger lumber for the frame the sheer weight will keep the deck in place through most everything but a direct hit by a tornado!
You may not want your deck to be level. Most builders will slightly tip a deck to control where the water runoff goes. A deck that is away from the house can be level, but if it is next to your foundation you want to be sure that the deck is slightly tipped away from the house. Famous last words... "I never had a leak around my foundation before!"
Use your "four corners" as a guide to digging out the rest of the ground under the deck, if needed for a slightly "below grade" deck. Clear away all grass and soil to a depth that will allow you to lay your joists across the deck blocks. Since you are using pressure-treated lumber, you need not leave any extra space under the dirt... dig out just enough to do the job!
Lay porous "landscape cloth" on the ground before building the frame. This will help prevent unexpected plant growth and still allow drainage. Do not use plastic tarps... they will not drain and may cause mildew problems and odors over time!
At this point you will need to construct your deck’s frame. Build the perimeter first and then fit the in the joists. What I suggest is to use joist hangers to secure the joists. For the easiest possible job, carefully locate and install the joist hangers BEFORE you construct the frame. Then, once the frame is in place and leveled to your satisfaction, you can measure and install the joists with the least amount of trouble.
After your frame is completed, squared and leveled, install a middle joist first... and be sure you don't deform the "squareness" of the frame. When setting this critical joist, be sure to measure across the frame at the joist to be sure that the distance is the same as at the ends of the frame. Satisfied? Once this center joist is nailed in place, you are assured of a square frame and the rest of the joists will lay in with ease!
Before you do any nailing, place either your deck blocks or patio blocks to add extra support and stability for the individual joists.
There are some circumstances where you might not want to close the ends of the frame. This is mostly for low floating decks that are slightly above ground level or in very damp conditions. For decks that are at or slightly below grade, I prefer to close the ends to discourage rodents and other small animals from making your deck their home. This isn't 100% foolproof, especially with those little devils called chipmunks... but it helps!
As with any project, preparation is key when you’re creating a quality composite deck for your family to enjoy for years to come. Whether you’re preparing to take on your own DIY outdoor project, or collaborate with a professional builder - it’s important to understand the best practices for installing Fiberon Decking material. That’s why we encourage customers, as well as contracted builders, to educate themselves on our materials’ best installation practices. In this post we’ll highlight important recommendations and requirements that should not be overlooked to ensure the best, finished look of your new deck.
General Storage and Preparation Tips for Composite Deck Boards
In order to protect your investment from the start, it’s important to store your composite boards in a level area. Keep products off the ground and covered on a flat, dry surface. Dark colors will absorb more heat than lighter colors and as such, will experience greater ranges in expansion/contraction.
The following preparation and installation procedures will result in less visible gapping:
1. Keep boards out of direct sun during storage and cutting processes, and through to installation, if possible. Never cut and install boards in direct sun assuming them to be at ambient temperature.
2. Longer boards have greater thermal expansion and contraction. Use short boards where possible for less visible gapping.
3. There is less thermal expansion and contraction along the width of the board as opposed to the length. Using splitter/divider boards between each continuous run of boards will result in less gapping.
4. Thermal expansion and contraction of the material can allow the boards to shift. Surface-fastening using heavy gauge (#9 or #10) quality composite deck screws will help keep the material in place.
Planning the Layout of Your Deck Boards
Careful planning of the finished deck layout will result in better looking finished projects. Fiberon composite deck boards are made to mimic the varied colors and grains of wood. Before you start installing your deck, it’s helpful to lay out the aesthetic pattern you want considering the wood tone variations and various grain patterns. For example, you may want to line up boards in the same wood grain direction for a uniform look. An alternating direction style can add visual interest to your project. Also consider using two colors of deck boards with the lighter colored boards in the field of the deck and the darker colored boards as design accents around the perimeter of the deck.
Deck Fastener Options
Fiberon decking materials are designed to be installed with either face screws or hidden fasteners. Phantom hidden fasteners are specifically designed for Fiberon side-grooved boards and provide a smooth, fastener-free surface.
Face fastening can be accomplished with hidden or regular surface fastening screws. Cortex hidden face fasteners are installed on the surface and have deck plugs that cover the screw heads for a virtually fastener-free look. Stainless steel or colored ceramic composite deck screws can be used for surface fastening also. However, pre-drilling is recommended to prevent ends from splitting and will result in a better looking finished project. Follow installation instructions carefully for a flush finish with the deck surface. For decks using metal joisting, specialized surface fasteners are required that install at a 90-degree angle only.
Best Results When Adding A Railing
When using surface fasteners to secure railing to a composite deck, joist location may affect the ease, price and method of the installation of the railing system. Leaving the required 1.5” spacing for surface fastening at the end of the board and 1” from the side of the board, requires two joists for every end-to-end seam. Board seams with double joisting can affect post placement for your railing system.
Thoroughly reading all installation instructions first will make for more successful projects. Failure to do so may result in a more difficult installation and may void the warranty.