How to repair a concrete floor

Wednesday December 5 2018


By Dorcus Murungi

Did you know that instead of hiring a builder to repair your concrete floor when it gets cracks you can do it yourself? You should however, remember that when working with cement-based products, always wear eye protection and waterproof gloves. Here is how you can do it yourself:

According to Richard Kigongo, an engineer at Digon Construction Limited, it is important for one to determine the scope of the problem. This he says you can do by using a ruler to determine the length and width of the area to be repaired if the condition does not define itself.

“This may include bumps, depressions, or ridges, small areas of shallow surface irregularities may be concealed with a floor levelling compound, rather than chipping out and replacing the actual concrete. Chip the surface of the concrete to remove any high material, and to create a rough surface for the repair cement mixture to bond in well. Clean the surface of the damaged area by removing any loose material such as dirt, oil, or grease and unsound concrete,” he says.

Grace Wanedeya, a civil engineer, explains that unsound concrete can be removed by using a hammer and chisel or with masonry grinding disk and a portable drill for small jobs, a chipping hammer will be all you need. However, she notes that larger repairs are much easier with an electric chipping hammer or even a jack hammer.
“Clean the dust and debris from the area you have fragmented. This will allow the new material to have a solid surface to adhere to,” she notes.

Wanedeya says after cleaning, one can mix the cement and material you will use to fill in the area you have chipped out.
“Mix the dry ingredients first, using a proportion of Cement (type I or II) to 2 1/2 parts clean masonry sand, add a polymerized liquid bonding agent to the dry sand or cement mixture, using enough to thoroughly wet the material and bring it to a stiff, plastic consistency,” she says.

Kigongo adds that it is necessary to wet the area where the patch is to be applied with clean, fresh water. And then you place the mixture into, or on the patch location, and work it into the space forcefully with the trowel to force out any air bubbles.
After that Kigongo advises that one should level the surface of the wet cement with the trowel, leaving it slightly higher than the adjacent edges, to allow for settling and shrinkage.

Then the person repairing should trowel the area with a steel finishing trowel when the patch material has become stiff. She explains that this will flatten and smoothen the surface, and cause cement paste to rise to the surface.
When all that is done Kigongo advises that a home owner should give the area another hour or two so that it sets up, or becomes hard, then finish wiping it.

“At this point, you may need to splash a little water on the surface to slow the drying, as well as making the finishing process somewhat easier,” she says.