Concrete is a hard-wearing and durable material with many applications, but it has some drawbacks – namely the fact that its very hardness and rigidity makes it vulnerable to cracks in the outside environment, whether it’s because of changes in temperature, ground movement, or excessive loads.
It is important to repair any cracks you notice as quickly as possible, or you run the risk of a small job turning into something more challenging. This is especially true in cold and wet weather, as water can freeze in the crack, causing it to expand even further.
The location and type of crack will affect how the repair is carried out. For example, a crack in the floor will require careful cleaning of the surrounding area, ensuring that there is no grease or oil around the area, but the most important thing, as any handyman will tell you, is the fact that preparation is the key to a successful concrete crack repair.
When you notice the crack, the first step is to protect it from water with a sealant. A flexible sealant from the hardware shop is the best solution, as it will allow the concrete to shift without worsening the crack.
Simply apply the sealant, using your finger to smooth it.
Using a hammer and chisel, carefully work away at the crack to take away any loose bits of concrete to a minimum of one-quarter of an inch. The sides of the crack should be parallel or bevelled in the manner of an upside-down ‘V’. This process is known as ‘keying’ and the aim is to make the base of the hole wider than the surface as this will help the bonding process with the existing concrete.
Use a brush to remove any rubble, dust and concrete crumbs. You could use a vacuum with a brush attachment for a large job.
Open the concrete patch bottle according to the instructions and apply it to the crack. Use a trowel or palette knife to ensure that the patch is filled effectively and to smooth out any cracks. This stage is a bit like icing a cake with royal icing.
Tip: If you are working on a vertical wall or the edge of a swimming pool, use a bucket or spread out plastic sheeting to catch any rogue bits of concrete from falling where you don’t want them to.
Leave overnight or for the length of time recommended by the manufacturer. Then check it again to see if it needs another layer of patch.
Finally, seal the patch with a water-based polyurethane sealant. This will prevent the concrete from absorbing water and stains in the future, making it stronger and less likely to crack again. It should dry quickly so you could apply a second or even third coat after only a few hours.
For more information about concrete repairs, or professional construction and demolition services, do not hesitate to contact the team at Drilltec. We are a Luton-based company operating across the UK and are leading experts in diamond drilling, offering a range of services using the latest technology and equipment.