There are many occasions after a rain that your yard is not usable since the grass is wet and soggy. Warm overcast summer days are a loss if you and the kids are stuck in the house. You can of course use patio block, poured concrete or stone to make your patio but wood seems to be a softer, warmer material to work with. You can add a ground level wood patio for less than a deck would cost and extend the number of days you can grille or just sit outside and enjoy the summer months.
You will need a fairly flat area to build your patio pretty much the same as if it was concrete or stone. Some minor hand grading can be done but if you need to use heavy machinery, the area is probably more suited to a raised deck than a patio. You will need to have a builder’s level and tape measure to set some elevations for the tops of the floor joists as you install them. If you are planning a great many yard projects you may want to consider buying a builders level instead of renting. One or two days of extra rental fees because you forgot to return it can pay for the level itself.
Setup the level and make sure it is perfectly level in all directions by adjusting the screws. Make sure the built-in bubble level is level in all directions as you turn the head itself.
Starting in any corner of the patio, take elevation shots in all four corners. For this example we will assume your first shot is 5′-0″ on your tape. Looking through the level glass, the left-to right cross hair is exactly at 5′-0″ or sixty inches. Now read the other three corners. We get readings of 4′-10″, 5′-3″ and 5′-2″. This means the patio area is fairly flat and by adding or deducting the shot measurements from the original 5′-0″ we see there is only a maximum of three inches in height difference to the high point and we may need to fill in two inches or so at the low point. Take a couple more shots in the middle area of the patio to make sure there are no real high points or low spots that will cause major hand work to level.
Our sample wood patio is going to be ten feet by ten feet in size. If at all possible you want to use one piece floor joists as they will result in less framing work and you only need to set the level grade at both ends of the joist. Once the ends are set, you can either fill in the middle to support the joist or dig out a little to allow the joist to sit on the level pads at both ends. Remember we are not digging out the entire patio. You only dig out enough to let the joists sit level with perhaps a three inch wide trench. Once the joists are all set level and the perimeter joists are installed, you will back fill all the loose dirt against the joists themselves. Nothing to haul away! If you were somewhat neat with your work by placing all your excavated material inside the patio area, the only evidence of digging will be the small slit you created around the edges of the patio for the perimeter joists. These areas will fill in with lawn very quickly.
A ground level patio requires that all wood be pressure treated or other type of wood acceptable for ground contact. Most if not all building departments do not require a permit for a patio but you should ask if one is required. Be sure to be very clear that this is a patio and not a deck. There are no footings, no support columns or beams and is not connected to a structure. In areas that have frost and freezing temperatures, the inspector wants to be sure no damage will result from heaving in the freeze–thaw cycles. Since the patio is free standing there will be no damage to structures. There are some areas that due to local Zoning regulations require permits for just about everything you do on your property so it always best to ask first.
A minimum floor joist size should be 2′ x 6″ PT but I prefer 2″ x 8″ PT for the extra rigidity the wider boards provide. If you can get the smaller lumber at a great discount or perhaps used or free it may be worth the extra time to install a series of wood blockings to stiffen the deck. If you are going to place a hot tub on the patio, stay with the larger lumber to prevent future sagging of the joists.
If your patio is going to be for general use for a bar-b-que grille and some chairs and a table, your joist spacing can be sixteen (16) inches on centers. If you expect heavier loads go for twelve inch centers. Layout all the joists in their respective areas including the rim or end joists. It is best to create the exterior box or rim joists first and get them set level. Nail or screw all the perimeter joists together. Screws are preferable as you will not be able to add fasteners after the joists are buried and the decking is applied. Using your two foot framing square, make sure the box is as perfectly square as you can make it. Measure corner to corner to assure these measurements are exactly the same. If they are, the box is square. Now using the level and tape measure, take measurement shots at the four corners and assure they are all exactly the same. You may have to dig a little or add some dirt under the joists but make sure if you are adding material under the joists that the dirt is compacted firmly. You do not want the deck to settle later.
Now that the perimeter box is level and square you may start adding the rest of the floor joists. The use of Teco hangers or other types of joist hangers is not really required as the patio is ground level and the joists will be supported their entire length by the ground below. If you have them and want to use them that is fine. Continue framing and constantly checking that the entire assembly has remained level and square. Once the framing is done, back fill all the joists with as much materials as available that you removed in the beginning. Remove any really large rocks unless you can bury them well below the bottoms of the decking boards.
I know you want to start installing the decking boards now but first we are going to run some landscape wiring under the deck. Figure out where you want to add some low voltage lighting, even if it is in the future, and run the wires now. It will be near impossible later on ot travel under the deck and you will use a lot less wire going from corner to corner under the joists instead of around the outside of the patio. I installed four three foot 4″ x 4″ posts in the corners and ran the wire up the posts for future lights keeping the ends where I planned to place the low voltage transformer.
If you installed your floor joists on sixteen inch centers, you must use 2″ thick (nominal 1 5/8″) materials for the deck boards. If you used twelve inch centers you may also use 5/4″ thick decking boards.
Using twelve inch joist centers also allows you to install your boards on a bias and create interesting designs in the boards themselves. Placing some board areas on diagonals to others can create many different designs. I strongly suggest that you use galvanized deck screws to install the decking boards. Screws will not pull loose over time as will nails. Screws also provide a tighter overall assembly when completed.
When you start your first deck board, have the first board hang over the edge of the perimeter joist approximately one inch. This provides a nice shadow line and any bowing on the joist below will not be noticeable. Make sure you allow enough board on the opposite side of the deck so the last board will also hang over the same amount. Do this on all four sides. Do not cheat on the amount of screws you use. If you are working alone, even with the best quality screw gun, this work can be very tiring. Take a break or two or come back the next day to finish. If you have a helper, pre-drilling holes for the screws saves tons of arm stress and will help prevent splitting of the boards.
Curved areas can be built with a little extra framing to support the decking and look fantastic when done. If you are creating a walkway to the patio the same framing methods as the patio are used. The framing underneath is straight and square but by cutting the decking on a curve you can create some really eye pleasing effects. My second patio but next to my first is seven inches lower and twice as big. After heavy rains when others are waiting for their lawns to dry out, we can go out and sit or cook and have a dry place to enjoy minutes later.