DO IT YOURSELF CONCRETE
Working with Concrete
How much concrete should you order?
|Area in Square Feet (width x length)||10||25||50||100||200||300|
Making the Pour
Once the concrete is spread well over the area and into all corners and crevices, use a screed board to drag off the excess. This is a two-man operation and at best is hard work, especially on larger pours. The screed board should extend past the form edges at least 3 inches on either side. Beginning on one end of the form, place the screed board over the form boards and then, using a side-to-side motion and at the same time pulling the board, inch it across the form boards to the opposite end. Screeding levels the concrete with the tops of the form boards, pulling excess concrete off. Any low spots will be visible and should be immediately filled and the area rescreeded.
The next step is to float the surface. Small projects can be floated with a wooden or magnesium float. This helps fill any small voids and works the aggregate slightly below the surface. On larger pours a bull float is used. Push the float away from you across the surface with the front edge slightly raised to prevent the blade from digging in. Then pull the float back at an almost flat angle.
The Marshalltown Rota-Leveler bull float bracket allows for easy changing of the float level on the push and pull strokes. Floating smoothes the surface and works some water to the surface
Then use an edger around the top edge of the form. This creates a rounded edge that won’t chip off when the form is removed. The edger should be held fairly flat, but keep the front tilted up slightly when moving forward and the rear tilted up slightly when moving backward.
Jointing is the next step on projects such as sidewalks and driveways. This prevents cracking the slabs. Control joints are normally spaced at intervals equal to the width of the pour. It is recommended, however, not to exceed 10 feet in any direction without a joint. The joint should be cut at least one-fourth the depth of the slab. A jointer tool is used for this step. Place a straight-edge across the surface and run the jointer along the straight edge to create a nice straight line. As with the edger, hold the front up slightly when pushing forward. Control joints in large slabs can also be cut after the concrete cures, using a masonry blade in a circular saw or concrete saw.
Next, use a float to smooth and level the surface. This will also help remove any marks left by the edger or jointer. For rough or textured surfaces, use a wooden float. For projects requiring a smoother finish, use a magnesium or aluminum float. Hold the float flat on the surface and move it in an arc, overlapping the arcs as you proceed. Don’t overwork the surface.
The final finishing step is troweling. Small projects can be hand-troweled. Marshalltown recommends a 14-by-4 or 16-by-4 trowel for most finishing jobs. The first troweling should be done with the blade held flat down on the surface. Again use the trowel in an arc, overlapping each previous arc by about 1/2 inch. The surface should be well troweled several times to produce a hard, durable surface. Allow the concrete to set up slightly for the additional trowelings. The proper time is when the sheen of water disappears and a footprint leaves less than 1/4 inch of an indentation. These trowelings should be done fairly vigorously and with the trowel tilted up slightly, pressing down on the “rear” edge.
A power trowel is the best choice for large slabs. These units can be rented at tool-rental outlets. Troweling will provide a smooth, hard and slick surface. These surfaces are easy to clean, but can be slippery when wet. Lightly brooming the surface with a shop broom after troweling can provide a rougher, more non-slip surface.
Creating a “Brick” or “Country Stone” Project
Place the WalkMaker level on the ground. (You may prefer to remove the turf first.) Mix the color with the water and then add it to Quikrete fiber-reinforced concrete according to the instructions on the package. Do this in a mixing tub or wheelbarrow. Fill the mold cavities with concrete. Smooth the surface on all edges with a pointing trowel until even.
Immediately remove the mold and move it adjacent to the section just completed. Repeat the process until the project is completed. Keep the surface damp for about seven days to allow the concrete to cure properly. After the entire project has cured for one week, sweep Quikrete mortar or sand mix between the bricks or stones. Make sure the materials are well packed down in the crevices, and then hose the excess off.