Want to turn that bare corner in the yard into a small patio? Or redo a patio that is cracked and settling? Well, concrete is a great variable to work with.
DEMOLITION (if applicable):
If you have an existing concrete structure, it is imperative to break up the concrete and remove it. Never pour concrete over existing concrete.
In the installations of a new 4-inch thick slab, excavate the slab area about 7 inches deeper than the desired finished height. Now backfill the area with 3 inches of gravel or other suitable sub base. Use a plate compactor to compact the area. This gravel will create a solid foundation for the concrete to be installed over.
Next step is to use a 2×4 form board to create a frame or border for the proposed concrete. When installing the form boards fasten corners with nails and stakes. The forms need to be doubled measured to insure heights and grades are accurate. Allow ¼ inch of slope for every 12 feet of run for drainage. Patios, sidewalks and driveways should slope away evenly from structure. Prior to installation of concrete, after forms are constructed metal mesh is installed to add structural integrity to the concrete.
Next step is to pour the concrete. Be sure when filling the form, the concrete mounds 2-3 inches above the form before leveling. Use a shovel or hoe to help move the concrete to ensure the entire form is filled. Then take a screen; this can be made of aluminum or wood, move it back and forth across the surface in a saw like motion. This will allow you to remove excess concrete from the slab. Add concrete to any low areas and repeat the last process. Now take a jitterbug, a masonry tool use to pack the aggregate in the concrete mix down and bring the paste to the top for finishing. Next, take the bull trowel and smooth out the concrete surface evenly.
Now the finishing process can begin, at this time you can apply salt for a salt finish, or for a bush finish, take a stiff bristle brush and lighting broom the concrete. Brush in the same direction as you move across the entire slab. Joints and breaks need to be cut into the slab at this time as well. Joint and breaks are made using a jointing tool to allow for expanding and contracting. Using a grooved jointer tool and a straight edge to cut a minimum of a ¼ inch joint every 8-10 feet in the slab. You can also use an edging tool and this time to shape the edges of the slab.
After the slab is finished being edged and jointed you can remove the forms. The concrete should be watered with a fine mist for the next 3-5 days for the curing process. In hotter areas, this process will need to occur more frequently so that the slab does not cure too fast. The curing process can be eliminated if the slab is treated with and acrylic curer or sealed immediately after.