There are many times after a rain that your garden cannot be used because the grass is wet and soggy. Hot cloudy summer days are a waste if you and the kids are stuck indoors. Of course, you can use patio blocks, poured concrete, or stone to make your patio, but wood seems like a softer, warmer material to work with. You can add an in-ground wooden patio for less than a deck would cost and extend the number of days you can grill or just sit outside and enjoy the summer months.
You will need a fairly flat area to build your patio in the same way as if it were concrete or stone. Minor manual leveling can be done, but if you need to use heavy machinery, the area is probably better suited for a raised platform than a patio. You will need to have a building level and tape measure to set some elevations for the tops of the floor joists as you install them. If you are planning a large number of garden projects, you may want to consider purchasing a builders level instead of renting. A day or two of extra rental fees because you forgot to return it may pay for the tier itself.
Set 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 your head.
Starting at any corner of the patio, take elevation shots at all four corners. For this example, we will assume your first shot is 5′-0″ on your tape. Looking through the sight glass, the crosshairs from left to right are exactly 5′-0″ or sixty inches. Now read the other three corners. We get 4′-10″, 5′-3″ and 5′-2″ readings. This means the patio area is fairly flat and by adding or subtracting the shot measurements from the original 5′-0″ we see that there is only a maximum of three inches of height difference at 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 yard to make sure there are no real high spots or low spots causing major handwork to level out.
Our sample lumber yard will be ten feet by ten feet in size. If possible, you want to use one-piece floor joists as they will result in less framing work and you only need to set the grade of grading at both ends of the joist. Once the ends are in place, you can fill in the middle to support the joist or dig down a bit to allow the joist to sit on the level pads at both ends. Remember that we are not digging up the entire yard. Just dig down enough to let the joists sit at the level of a trench maybe three inches wide. Once all the joists are level and the perimeter joists are installed, you will fill in all the loose soil against the joists themselves. Nothing to wear! If you were a bit neat with your work by placing all of the excavated material within the patio area, the only evidence of excavation will be the small groove you created around the edges of the patio for the perimeter beams. These areas will fill up with grass very quickly.
An at-grade patio requires that all lumber be pressure-treated or another type of lumber 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. Make sure you are very clear that it is a patio and not a terrace. There are no foundations, columns or support beams and it is not connected to a structure. In areas that have frost and sub-zero temperatures, the inspector wants to make sure no damage is caused by freeze-thaw cycles. Since the patio is freestanding, there will be no damage to structures. There are some areas that, due to local zoning regulations, require permits for almost everything you do on your property, so it’s always best to ask first.
Minimum floor joist size should be 2′ x 6″ PT but I prefer 2″ x 8″ PT for the extra stiffness the wider boards provide. If you can get the smaller lumber at a deep discount or maybe used or free, it may be worth the extra time to install a series of wooden blocks to stiffen the deck.
If your patio is going to be commonly used for a barbecue grill and a few chairs and a table, the joist spacing may be sixteen (16) inches on center. If you expect heavy loads, opt for twelve-inch centers. Distribute all joists in their respective areas, including rim or end joists. It is best to create the outer box or rim joists first and level them. Nail or screw all perimeter joints. Screws are preferred as you will not be able to add fasteners after the joists are buried and the deck is in place. Using your two-foot framing square, make sure the box is as perfectly square as possible. Measure from corner to corner to make sure these measurements are exactly the same. If they are, the box is square. Now, using the level and the tape measure, take measurements at all four corners and make sure they are all exactly the same. You may have to dig a bit or add some soil under the joists, but make sure if you’re adding material under the joists, the soil packs down firmly. You don’t want the deck to settle later.
Now that the perimeter box is level and square, you can start adding the rest of the floor joists. The use of Teco brackets or other types of beam supports is not really necessary as the patio is at ground level and the beams will rest their full length on the ground. If you have them and want to use them, that’s fine. Continue framing and constantly check that the entire assembly has remained level and square. Once the framing is done, refill all the beams with all the available materials you removed at the beginning. Remove really big rocks unless you can bury them well below the bottom of the deck boards.
I know you want to start installing the deck boards now, but first we’re going to run some landscape wiring under the deck. Find out where you want to add low-voltage lighting, even if it’s in the future, and run the wires now. Later on it will be almost impossible to get under the deck and you will use much less cable to go from corner to corner under the rafters instead of around the outside of the patio. I installed four 4″ x 4″ three foot posts in the corners and ran the wire through the posts for future lights keeping the ends where I planned to put the low voltage transformer.
If you installed the floor joists on sixteen inch centers, you must use 2″ thick materials (nominal 1 5/8″) for the deck boards. If you used twelve inch centers, you can also use 5/4″ thick deck boards.
Using twelve-inch joist centers also allows you to install your boards on the bias and create interesting designs on the boards themselves. Placing some areas of the board diagonally from others can create many different layouts. I strongly suggest that you use galvanized deck screws to install deck boards. Screws won’t loosen over time like nails. The 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 rim joist about an inch. This provides a nice shadow line and no bowing will be noticeable in the joist below. Be sure to leave enough board on the opposite side of the deck so that the last board also hangs over the same amount. Do this on all four sides. Don’t cheat on the number of screws you use. If you are working alone, even with the best quality screw gun, this job can be very tiring. Take a break or two or come back the next day to finish. If you have a helper, pre-drilling the screw holes saves tons of stress on your arms and will help prevent splitting your boards.
Curved areas can be built with a little extra framing to support the deck and look fantastic when finished. If you are creating a walkway to the patio, the same framing methods are used as for the patio. The frame underneath is straight and square, but by cutting the deck into a curve you can create some really eye-pleasing effects. My second patio, but next to the first, is seven inches lower and twice as big. After heavy rains when others are waiting for their grass to dry, we can go out and sit or cook and have a dry place to enjoy minutes later.