For added comfort, wear knee pads. These will prevent pain and bruising when you kneel down on the concrete. If you don’t have knee pads, you can also lay a padded mat in your work area.
If you make a mistake and chisel off too much, don’t worry. You can patch those holes the same way you’re patching the main crack. Don’t chisel just for the sake of it. If the edges are already squared and straight, then skip this step.
Don’t worry if there is dust or smaller debris left behind. This step is only to remove large pieces that a vacuum can’t pick up.
If you don’t have a shop vac, don’t use a normal vacuum cleaner. Concrete shards could damage it. Instead, use a fine brush to sweep up dust and smaller debris as well as you can.
Generally, you don’t have to wait for the water to evaporate before applying the bonding agent. However, read the instructions on the product you use. If it tells you to apply the agent to dry concrete, then wait for the water to dry.
Bottles of bonding agent are available at hardware stores. Ask an employee for product recommendations if there are multiple to choose from. The product you use may give specific directions on the amount to use and drying time. Follow the instructions provided.
If the mortar is too watery, it won’t bond well. Add more dry mortar to make it thicker if you have to. The amount you use depends on the size of the hole you have to fill. Most packages have directions on how much to use for different sizes. The recipe and mixing time may vary for different products. Always follow the instructions on the product you use. Always wear gloves, safety glasses, and a mask when mixing mortar. [8] X Expert Source Gerber Ortiz-VegaMasonry Specialist Expert Interview. 10 March 2020.
Be sure to press the mortar against the edges of the damaged area as well. You need a strong bond throughout the entire crack.
Repeat this motion if the mortar is still not level. If the hole is round, then don’t worry about working lengthwise. Just pull the trowel across the surface to even it out. Note that the mortar won’t be completely flush with the surface of the concrete yet. This step just levels out the top.
You might need to repeat this several times. Continue working around the mortar until it’s all even with the concrete.
Don’t let anything you use to cover the mortar touch it directly. A sheet, for example, could get stuck on the mortar. If you’ve repaired an indoor floor, then this probably isn’t an issue unless a window focuses the sun right on the repair. Keep the window closed until the mortar dries.
Check your product instructions to see if there is a different drying time. If this floor was in your garage, wait a week before driving over it with your car.
