Deck supports can be built very simply. Most of the work involved is in laying out the site and finding the location for each support. Also involved is mixing and pouring concrete and then attaching the post to the concrete. Once this first step is completed, however, you can start the carpentry work.
Things You'll Need
- Concrete mix
- Shovel or post hole digger
- Tape measure
- Post anchor
- Wire mesh
How To Build Deck Supports
The first thing that you need to do in the construction of deck supports is to lay out the area of the new wooden platform that you are planning to build. Your deck might adjoin to your house or it could be a free standing structure in your backyard. In either case, construction remains virtually the same, so all you need to do is once the calculating is done is to mark each spot where a deck support piece should be. For simplicity, we will plan on building a small free-standing deck with supports that are only located along the perimeter of the new structure.
Next, dig a whole for each concrete footing. A post-hole digger is the optimum tool for this task, but a shovel can be used if need be. If you are using the post-hole apparatus, then make sure the hole is at least a foot wide and if you live in a northern climate, you will have to go beneath the frost line. People who live in the frost-free region of the country should allow for a concrete pier that is at least two-feet deep.
You should lay out each and every location for all the supports at one time, and check your accuracy with a string. If you have four supports on one side of your deck, then a piece of string stretched out from the first pier to the last will let you know that all the support locations are in a straight line. Also make sure the four corners are square. This is done by checking the diagonal measurements. In a perfect square or rectangle, both diagonal lengths will be equal.
Now it is time to mix up the concrete that will be placed in each hole to form the base of the deck support. Unless you are building a very large deck, the best way to go is to buy bags of ready mix concrete from the local building supply outlet. Also it is a good idea to purchase some wire mesh that will be placed in the concrete mixture before it becomes hard.
Next, mix the concrete in an old metal wheelbarrow if you have one. (If you don’t have a wheelbarrow, then a half-sheet of plywood laid out on the ground will work.) Make sure the concrete is mixed thoroughly and then place it in the empty hole. Then, take a long piece of wood like a two by four and repeated stir the concrete mixture that is in the ground with an up and down motion. This is done to remove the air pockets.
Once each footing is filled, you will need to top off each pier of concrete at ground level, but don’t forget to insert the wire mesh before you do. Go ahead and cut your wire mesh into small pieces and insert the pieces into the wet cement. Make sure all the wire mesh is submerged in the mixture. Then, take a small block of wood like a piece of a two by four and gently tap on the mixture until it appears level. Since it is not a good idea to put wood directly next to concrete you will need to purchase some metal anchor posts at the same place you bought your concrete. They come in various sizes to fit whatever piece of lumber you happen to use for your deck support. The most likely sizes will be 4” X 4”, 6” X 6” or 8” X 8”. Note the larger your lumber size, then the smaller number of piers you will have to build.
Now place one anchor in each pile of concrete while it is still soft. That will be within the first half-hour after the concrete mixture has been put together. If you are setting more than four corner piers, you will have to be very careful when you lay out the anchors, so that every post sits in a perfectly straight line. Don’t forget the string. If you lay out the metal brackets for the two end piers first. That means go right ahead and stick them in the concrete. Make sure they are level. You can even use a short six-inch level to check this out. Now run a string so that in runs right over the center of the two metal brackets. Any additional brackets should be placed in the wet concrete, so that the center of the anchor lies directly below the string line.
Finally, after the concrete has set up for twenty-four hours or more, it is time to begin the woodworking phase. (Make sure overnight temperatures are above freezing, because colder temperatures can weaken the structural strength of concrete.) There are two ways that one can go with the wood. The first is to use pressure treated woods like pine or fir that are structurally strong, but do contain all the pressure-treating chemicals. Or you can use a wood that is naturally resistance to rot and insects, but not as structurally sound. Redwood and cypress fit into this latter category, but you will have use bigger pieces of lumber to compensate for the lost of strength.
After you have acquired your lumber, the last step is to cut each wooden post about six inches longer than need be and place it in the bottom of the anchor. Then nail the sides of the anchor to the post and you are all set for the next stage in building a deck. (You should always purchase an anchor that can be attached to the post by driving a nail or screw through the metal into the side of the wooden post. Never buy an anchor that only attaches to the bottom of the wooden post.) Please note: There are some that might prefer to cut each post to length, instead of leaving them long like I have suggested. That is an alternative way of constructing a deck, but it also entails an extensive discussion of the next phase of construction. Please keep this in mind as you proceed, but remember that the concrete piers do not have to be at the same height, after they are all poured, but they do have to be in alignment, and the overall structure should be square.
Tips & Warnings
- Make sure you dig below the frost line when you put in the piers.
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