If you have a concrete path, patio or garden wall that is generally in good repair but does have a few knocks and cracks, and you don’t want to go to the trouble or expense of replacing it, here are a variety of quick fixes for repairing concrete
Each product is for a different method of repairing concrete, and is explained separately. Before purchasing materials, check the various methods and images to find which is most appropriate for your repair
Before repairing concrete, make sure the cracks and surrounding surfaces are clean, dry and free of dust or debris. Oil, grease, paint, other stains or chemical cleaning products must be removed prior to using any of the materials, as they may affect the bonding or curing processes
1) For cracks up to 1/4inch (6mm) width (Horizontal surfaces only):
CONCRETE CRACK SEALANT
This is ideal for long skinny cracks, and involves very little labour.
The crack sealant is a latex-based liquid, concrete-coloured, and comes in an easy to apply bottle
Pour the sealant from the bottle, overfilling the crack slightly to allow for settling and shrinkage. Multiple layers can be built up in deep cracks, as the sealant levels.
Pouring too much into the crack is not a problem, as it will spread and self level on the concrete surface
Because the sealant is applied directly from the bottle, and is self-levelling, you don’t have to mess about smoothing it over with your finger or a knife
2) For shallow holes and dips less than 1/2inch (13mm) depth (Horizontal surfaces):
CONCRETE PATCHING MIX
Patching compounds come in various forms from dry powder you mix with water to ready mixed
If using dry powder, check it already contains hardener and bonding resin
Follow the manufacturer’s instructions and mix to a thick soup-like consistency
Pour into the hole. Wait for it to thicken and start setting then smooth with a wet trowel
3) Cracks up to 1/2inch (13mm) width (Walls & Floors):
CONCRETE REPAIR CAULK
Concrete repair caulk is latex-based and blended with sand. Unlike regular caulks, this means you can apply it in multiple layers, allowing each layer to dry inbetween. However, for deeper cracks it’s a good idea to use foam backer rods to fill the crack first. Push the rod into the crack with a screwdriver. Do not use caulk to fill expansion joints (see section 7)
Smooth with a trowel to match the surrounding surface immediately on completing filling the crack, as it will begin to form a skin within 20 minutes and will harden completely in 1 to 2 hours
4) Cracks over 1/2inch (13mm) width, and holes, edges, remodelling (Walls & Floors):
Mix quick-setting cement with water to a thick clay-like texture that you can push into cracks.
It’s a good idea to add an acrylic fortifier. This will help to strenthen the cement and increase bonding
Quick-setting cement can also be used for to rebuild chipped edges, corners and missing pieces of steps, slabs and walls, holding them in place with wooden boards until set if necessary. Brilliant for holding fence and pergola posts in place too
5) Cracks and holes in very wet areas and concrete water features:
Hydraulic cement is extremely quick-setting and can be used for repairing concrete while very wet, if water is pouring through, or even underwater!
Mix to a thick putty, closely following the manufacturers instructions, push into the fissure, wait 5 minutes, then slice off the excess with a trowel or knife
Hydraulic cement actually stops water so is ideal for sealing cracks and holes to stop leaks in any concrete construction, sealing holes around water pipes, and to repair concrete water features, fountains, ponds, pools, bird baths and planters etc
6) Cosmetic surgery for unsightly or repaired surfaces (Floors & steps):
Mix the resurfacer as per the manufacturer’s instructions, to a pouring consistency
Resurfacer starts to set in approx 20 minutes so you have to work fast
Spread the resurfacer out with a trowel to ensure the whole area is covered. Resurfacing compound is self-levelling so you don’t have to worry about it being too even.
After 5-10 minutes you can use a broom to sweep over the surface in one direction if you want to make it more anti-slip, this should be across the direction that foot traffic will take
After 15-20 minutes remove the rods from the expansion joints as you will need new ones when you reseal
The skim layer should be ok to walk on after 5-6 hours, but obviously the longer you leave it the better