Recommended Tools for Laying Concrete
Pointing Trowel
Wood Float
Groover
Edger
Finishing Trowel
String or Line
Lumber and Nails
Saw
Hammer
Broom or Rubber Float
Water Hose
Mixing Tub and Hoe (if mixing your own concrete)
Bull Float (for larger concrete slabs)
Square Bottom Shovel or Kumalong
Measuring Tape
4 Ft Level
Sealer |
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Laying Concrete
Concrete construction is easy and rewarding. It will withstand many hard years of use with little or no maintenance while adding value to your home.
The best way to start your concrete project is to plan it in detail.
To determine the amount of concrete you will need for your project, stake and measure the area for approximate dimensions. Any concrete supply center will help you determine how much you will need if you supply them with the dimensions. For smaller jobs, you will most likely want to mix the concrete yourself. For larger jobs, buying ready-mixed concrete from a concrete supplier is far more practical and less time consuming. |
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Preparing the Area
The staked area must be prepared by removing all the sod and earth to a depth of at least 4 inches. For heavy load bearing surfaces such as driveways and garages, the concrete should be 4 to 6 inches thick with reinforcing rods or mesh. For other projects, reinforcing rods or mesh are not necessary, and 3 to 4 inches is usually adequate.
The bottom surface of your prepared area should be uniform and close to level. Any loose soil should then be compacted with a hand tamper. To assure proper curing, the area should be sprayed lightly with water. This will minimize moisture loss from the concrete. |
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Building Wooden Forms
Using 2” x 4” lumber and stakes, construct forms around the prepared area. Along the outside of the prepared area, drive stakes into the ground approximately 4' apart. Nail the 2'' x 4” boards to the stakes, keeping the tops of the stakes slightly below the height of the boards. On larger areas it is helpful to string a line to guide the placement of the stakes and boards. (FIG. #1.)
For curved areas, use 1/4'' plywood strips and place tine stakes closer together. If the area is larger, you will need to place 2" x 4" stringers to divide the larger area into equal smaller sections. It may be necessary to place expansion boards in between the smaller sections to compensate for contraction and expansion of concrete due to freezing and thawing. (FIG #1) Contact your local building supply center for more detail and availability of materials for this procedure.
Outdoor projects that adjoin a building should be sloped slightly so that water runs away from the building. Use a level to check the slope, making sure that the angle of the slope is uniform for the entire area. |
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Pouring the Concrete
Pour the concrete to the top of the 2" x 4" form boards. Using a square bottom shovel or a Bon Kumalong, push the concrete to the corners to assure they are filled. You may want to pour a little extra concrete into the center of the area to compensate for settling in low spots. Do not overwork the concrete, as it tends to separate the concrete mixture, bringing the water to the surface.
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Screeding
"Screeding" or leveling the concrete to the top of the boards is more easily accomplished with two people. You can use any 2" x 4" or a Bon Screed Board. Be sure it extends at least 6 to 12 inches beyond the 2" x 4" form boards. (FIG. # 2)
Starting at one end, work the 2x4 across the concrete in a see-saw fashion, making sure the screed board is resting on the form boards at all times. This will remove excess concrete from high spots and fill in any low spots. Concrete will pile up in front of the Screed Board, so you will need someone spreading this excess material with a shovel toward any low spots. If low spots still exist; add some more concrete and re-screed. |
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Floating
Once your concrete is leveled, you will want to float or scrape the surface to produce a finer, more finished texture. Holding your wood float level, move it in long arch-like sweeps lightly along the surface of the concrete. This process will push any larger sediment (rocks) below the surface and will bring a lighter, watery mixture called "cream" to the surface. Remember not to overwork the concrete. (FIG. #3)
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Edging
Following the floating procedure, run your pointing trowel along the edge of the filled area, against the form boards, to produce a narrow furrow that slightly separates the concrete from the boards. Place your edger along the form with its lip in the furrow, keeping it level with the concrete surface. Run the edger against the form boards the length of the prepared area. This process insures a rounder, smoother edge that will resist chipping. (FIG. # 4)
Grooving
Before the concrete becomes too hard, you will want to groove the surface to produce expansion joints. Grooves should be no wider than 10’ apart. On smaller jobs, they can
be spaced evenly apart from each other. To determine the best spacing length, use the width of your prepared area as a guide. To produce straight groove lines, place a wood strip along the surface that runs the entire width of your working surface. Holding the groover level, run it along the wood strip pressing just hard enough to insure that a distinct groove line becomes visible.
Troweling
Troweling will produce a smoother, finer finish to your concrete slab. Remember, the more times you trowel the surface, the smoother your finish will be.
If the surface you’re preparing is too wide to reach across, you will need to support yourself in the prepared surface with two 12" x 24" boards. (These can be easily made with scraps of lumber.) The slight indentation caused by these boards on the concrete surface will be smoothed out when you trowel over it as you work your way backwards from one end to the other. You will work with the wood float in one hand and the finishing trowel in your other. Kneeling
on the knee boards, lean forward and support yourself with the float. With the same arch-like sweeping motion you used when floating, run the trowel flat along the surface. (FIG. #5) Use slightly more pressure this time, and overlap the sweeping arches by approximately 1". Remember, start at one end and work toward yourself, moving backward as you go. For each additional troweling you will want to raise the leading edge of the trowel slightly in order to create a smoother finish.
For a non-slip surface, you may want to brush the surface of the concrete lightly with a broom, creating a rough, textured finish. (FIG. #6)
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Sealing
As a final touch, your concrete slab can be sealed against outside eroding forces.
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