Concrete Reasons To Repair Cracks And Holes In Your Patio
Busting concrete. Digging trenches. Laying new forms. Screeding and curing cement. Pouring cement is hard work, especially if you have to replace your concrete patio because of cracks or holes. But can't those defects be repaired any other way?
Patching cracks in concrete is one of the most common masonry repair jobs. The key is to first determine what is causing the crack to begin with. If it's caused by a structural problem, fix it first; otherwise, the crack will only get worse.
For shallow cracks or holes in concrete, use a baby sledge hammer and a cold or brick chisel to break out the old and crumbling edges from the crack. Chisel the crack or hole to about a one inch depth - if it isn't already. The sides of the crack should be vertical; the hollow will form a sort of key for the patching material. The trick is to create a new area that's wide and deep enough so you don't have to feather out the new cement to a thin edge. Thin edges break.
A word of caution: always wear safety goggles and heavy gloves when chipping concrete.
After chipping the concrete, use a broom, followed by flushing the surface with clean water, to remove all the dust and debris from the crack or hole. Sweep away any standing water with a broom, but be sure to keep the area damp. For larger surface holes and cracks, roughen the hole first with a cold chisel to help hold the patch in place.
Now you're ready to do the patchwork. Fill the crack or hole with the cement mixture, using the straight edge of a board to level it. Then let the job set for about 30 minutes and finish the surface with a trowel so it matches the surrounding concrete. (Most rental centers rent a wide assortment of concrete finishing tools.) If the patch is in a vertical surface, make the concrete mix thicker.
Note: You can buy special bonding materials that can be brushed onto the area and mixed with the cement to help keep the patch in place.
Sometimes holes in newly placed concrete walls will develop due to improper tamping or because aggregates in the mixture have lodged in center spots. For these holes, repair following the same instructions as you would repair a crack. If, however, when cleaning out the hole, the hole becomes larger and larger (as they sometimes tend to do) use reinforcing pins, rods, carriage bolts or lag screws to help hold the concrete patch in the break. Pins must be one-half inch and lower than the finish surface. Drill holes for the pins with a power drill.