There are many different types, styles, materials and processes for building decks. I will be explaining a simple free standing square deck using pressure treated materials.
The first step in building a deck is to clear and flatten the area it is always better to work off a level surface. Once the area has been levelled and cleared of debris the square outline of the deck should be marked on the ground. You should always make your deck square to existing structures. When the outline of the deck has been marked you can then mark where the support post holes will go.
The size of the deck will determine how many support post you should have. We will be building a fairly small deck so only four support post will be necessary. The post holes should be marked evenly spaced in the four corners about two feet on both sides inside the deck outline. Once the hole position has been marked you can dig your post holes depending on the height and size of the deck the depth and size of the holes will change.
For instance if you deck is only ten feet by ten feet and two feet of the ground, like the one I am explaining than all you need is a two foot deep hole that is about six teen inches in diameter. But if it is a much larger deck sonotubes will need to be poured at a much deeper depth. Because our deck is quite small we will be using peer blocks instead of sonotubes. Peer blocks are precast concrete blocks with grooved centers for your support posts to fit in. Once the holes have been dug they are then filled with clear crush then compacted using a hand tamper. This will give a strong base for the peer blocks to sit on preventing the deck from sinking. Place the peer blocks on top of the crush filled holes then with a string line make sure they are all square and level to each other and the correct distance from the deck outline.
When all your peer blocks are set cut four, 4×4 posts to the length needed. If your peer blocks are set at ground level the length of your posts will be the finished height of your deck subtracted by the height of your, joists and decking material. We will be using, 2”x8” joists and 1”x6” deck boards. So if our finished deck height is 24” then subtract 8” for the joists and 1” for the deck boards for a total of 9. So 24 subtract 9 and our posts need to be 15”. Insert the posts vertically into the center grove of the peer blocks, they should fit snug and may take a couple hits from a hammer to drive them down fully. Once your posts are erected make sure the tops of the posts are all level to each other.
There are many different types of beams for different deck applications. For our deck we will be using two 2×10’s attached to either side of the posts all running parallel to each other. The 2×10’s should be attached using lag bolts or RSS screws. Once the beams have been installed and are all perfectly level to each other you can run your joists. We will be using 2×8’s for our joists lay them on edge perpendicular to your beams. Starting from one end place a joist every six teen inches on centre with one on the other edge that may be a different width apart. It is a good idea to add joist hangers for added structural support. Then you should add 2×8 blocks evenly spaced between each joist.
The last step is to lay your deck boards. Running the deck boards perpendicular to your joists screw them down two screws on every joist. A small gap should be left between deck boards in order for water to drain.