Whether you use a patio as a place to relax, for recreation or for entertainment, it can be a valuable addition to your home. Don’t restrict your thinking to a plain troweled-smooth gray concrete patio. This is the kind most concrete contractors in Salt Lake City will put in for about 1 dollar a square foot. Consider, instead, pebble concrete, bricks, concrete tiles or flagstone. If you’re going to do the job, you may as well do it with grace. Many patios are made one-fifth the area of the house. A 1500-square-foot house would get a patio of about 300 square feet, or 15 x 20 feet square. How- ever, a patio as small as 12×12 feet can be arranged for pleasant outdoor living. A large patio can be extended to include a porch or pool deck. When you decide where to put the patio, consider access to the house, view, sun, breeze, privacy and drainage.
Contrary to what many think, a cast-in-place concrete patio need not be built on a crushed stone or sand subbase. In most cases you can build it right on the ground. The only places you need granular materials under a concrete patio are soft, mucky spots or those with poorly drained soils.
A patio should be sloped away from the house inch per foot in order to drain. Avoid getting low spots or “bird baths” that catch water.
To build a concrete patio, dig out all sod and black dirt in the area of the patio and several inches beyond. The extra digging will make room for your forms. Remove all plants, bricks, wood, large rocks and other debris. Level the subgrade and compact it with a tamper. You can make the tamper of a 5 or 6-foot 2×4 or 4×4 by nailing on a 6×6-inch piece of plywood.
Lay out 2×4 forms and nail them securely to 1×2 or 2×2 stakes driven into the ground at 4-foot maximum intervals. The use of a level and stringline will help you get the forms at the right level and slope. If you use redwood, cedar or creosote soaked fir or pine form lumber, the forms can be left in place. They help section it off and add interest to the completed patio. Grids of 3 to 5 feet in size are convenient. The maximum should be 10×10 feet. Leave openings in the patio where you want them for sandbox, planter, pool, etc. Simply form around the opening, placing it next to a control joint. There’s no need to limit yourself to straight patio edges. Long-radius curves can be formed with 1×4 lumber instead of 2×4’s. Short-radius curves can be formed with 4×4-inch plywood or hardboard strips. Cut plywood so the grain runs vertically when in place. This makes it easier to bend.
The old trick of laying out a garden hose to outline smooth curves is still a good one. Bend the form around firmly driven inside stakes placed according to the hose. Then drive outside stakes and nail the form to them. The form will hold its shape after the inside stakes are Pulled.
Along curves the form stakes should be placed every 2 feet. Put a lx4 form stake at every joint in the forms. Position a 2×2 stake at the joint between a curved and straight section to hold the forms in alignment at that point (see drawing). Place isolation joints at every existing slab and wall. If the special ½x4-inch asphalt-impregnated joint material isn’t available, you can use a pair of ½x4 pieces of beveled siding. Remove the siding after the concrete has set and fill the joint with liquid asphalt to keep water out. Once the forms have been set, use a template to help smooth the subgrade to the uniform 3-inch depth. Soak clay soil a few days before placing concrete on it. There should be no standing water.
To find the amount of concrete needed for a 4-inch-thick patio cast using 2×4 forms, see the table. For a patio 12×25 feet, for example, first multiply the dimensions and find the square feet to be paved: 12×25=300 square feet. According to the table you’d need 3.3 cubic yards. Order 32 cubic yards if you use ready mix, or order enough materials to make that much mix-it-yourself concrete.
Air-entrained mix should be used. Place, finish and cure as described previously. Outside edges of the patio should be run with an edger. So should the intermediate edges along forms that are being left in. If the forms don’t do it, the patio should be jointed into 10×10-foot or smaller sections using a jointing tool. No wire mesh or reinforcing steel is needed in a simple patio slab. If the forms aren’t to be left in, they can be stripped, scraped clean and the lumber reused. Avoid trying to saw used form lumber with anything but a carbide- tipped blade. The small amount of concrete left on the wood’s surface will tear heck out of your saw blade. If you’d like to go the easy route you can begin by calling professional concrete contractors in the Salt Lake City area.
Bricks, make good looking patios, too. The bricks should be hard-burned ones. Use the easy mortarless method. Brick pavers vary in thickness from 12 to about 2 inches, depending on the manufacturer. Face sizes are about 4×8 inches, though usually a little less. The important thing is that they be twice as long as they are wide to take full advantage of pattern possibilities. Regular bricks without holes aren’t very suitable for mortarless paving. They are dimensioned to accommodate mortar joints and don’t fit up well into many bonds without mortar.
Dig out an area about 4 inches deep as the first step in making a brick patio. It should be smooth and as even as you can get it, yet should slope away from the house 1/8 to 1/4 inch per foot. Fill any low spots with well tamped earth. Frame two adjoining edges of the patio with bricks set on edge in rows. Place these in a trench dug 2 inches deeper than the rest of the excavation. Spread 1 inch of sand and smooth it out. Roll out a layer of 15-pound asphalt roofing felt over the sand. This helps to keep the sand level and discourages plant growth through your patio. No Guarantees.
Begin laying paver bricks at the corner where the edging has been placed. See some of the possibilities for patterns in the illustrations. When the whole patio has been paved, edge its other two sides with bricks set on edge.
A low-cost concrete curb can serve as an alternate edging for a brick patio. So can a well-staked wood form. Each is left in place. Even well established turf can serve as an edging.