How To Repair Sidewalk
Concrete removal and replacement is the traditional method for sidewalk repair when the damage is so extensive that alternative methods are not enough to make the necessary repairs. Today there are a wide variety of sidewalk repair technologies available that, when implemented correctly, can result in major savings of both time and money.
In some instances if the sidewalk concrete is in good condition and there is only a vertical misalignment along the seam between slabs (See Stub Toe and Longitudinal Slope in Sidewalk Inspection Criteria) it may be possible to correct the problem by one of the following methods.
A sidewalk permit is only required for the replacement of sidewalks. The permit can be obtained through the Building and Zoning Department. You may only hire a contractor registered, licensed and bonded with the City of Oregon to replace your sidewalks. A list of licensed sidewalk contractors can be obtained through the https://oregonohio.org/departments/building-zoning/.
Contact the Department of Public Service at (419) 698-7047 to determine if your sidewalk could be repaired by any of these methods or for additional information related to these items.
1. Concrete Raising (Slabjacking)
- Concrete raising is a repair method that lifts concrete sidewalk slabs back to their original position by pressure injecting cement or non cement material under the sidewalk. Holes are drilled through the slab and grout is injected to raise the concrete slab or to fill the voids under them. Although it is less costly than replacement, it is only effective on sunken sidewalks. There are many contractors that specialize in performing this type of work.
- This is a good alternative when the sidewalk concrete is in satisfactory condition with no cracks or structural defects. One draw back to this method is the greater the slab needs to be adjusted the greater the possibility of the slab settling in the future.
2. Concrete Grinding:
- Concrete grinding is a relatively new technology used to remove trip hazards in concrete walkways by reducing slight protrusions on a concrete surface by removing a thin layer of concrete. After grinding, the surface is left even on both sides with a gradual slope instead of a dangerous edge.
- Concrete grinding is a good alternative if the lip (stub toe) between concrete slabs is between 1/2″ to 1″.
- Grind off the hazard so that the walk has a gradual slope or transition.
- For a ½-inch lip (stub toe), grind back 6 inches. For a (maximum) 1 inch lip (stub toe), grind back 12 inches
3. Repairing Cracks, Gaps or Pits in your Sidewalks
- Cracks in sidewalks must be enlarged before they can be satisfactorily repaired. Enlarge the crack along its entire length with a cold chisel and hammer.
- Make the crack wider at the bottom than at the top. This is known as undercutting. It helps to bond the new concrete with the older concrete.
Undercut the crack to a minimum depth of 1″. The depth of the undercutting depends on the size and depth of the crack to be repaired.
- After the crack has been thoroughly undercut, remove all loose material and brush the area with a wire brush.
- Use a garden hose or a tire pump to blow or wash away the dust in the crack.
- fig3-1The new concrete patch will hold better if a concrete adhesive is used first. There are many types of concrete adhesives. Acrylic resin-a milky fluid-is one common type. Brush the adhesive into the undercut area and allow it to dry until it becomes tacky.
- If you do not use a cement adhesive, thoroughly brush and soak the area to be patched. Moistening the area prevents the old concrete from absorbing all the moisture in the concrete patch. Although it should be moist, no water should be standing on the area where the patch is to be applied.
- For small patching jobs, use a pre-mixed concrete patch. If you use ready-mix concrete patch, all you need to add is water.
- If you mix your own concrete patch, use one part Portland cement to two-and-a-half parts of fine, clean sand. Heavier concrete patch jobs call for one part of Portland cement to two parts of sand to three parts of gravel.
- Tamp the concrete patch mix tightly into the undercut area. Be sure to fill all areas completely.
- fig3When the mixture begins to set, smooth it down with either a metal trowel or a wooden float. Use a metal trowel for a smooth finish. For a rough surface, use a wood float for the finishing job.
- After the patch is completed, allow it to dry for about two hours. Then cover the patched area completely with plastic sheeting or boards.
- Keep the area covered for about five days. Lift the cover once each day to wet down the repaired area, permitting the new concrete to cure correctly.