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How to level a Concrete Floor

When preparing to lay a new floor, you must make sure the surface underneath is level to ensure that defects don’t show through. Having an uneven subfloor can cause uneven wearing and potentially damage your new flooring. So, how do you fix it? Here at Leader Floors, our experts are on hand to help you create a level concrete floor that you can then lay your flooring on top of and have ease of mind that it will stay in premium condition. 

If your concrete flooring doesn’t require repair, you can make sure that it is level by using a latex self-levelling compound. Make sure to repair any minor cracks or holes and then pour the compound onto the floor and trowel it until it’s smooth. If trowel marks are visible after a couple of minutes, make sure to smooth the compound again. Follow our quick and easy steps to levelling your concrete floor in the neatest way possible.

Step 1: Prepare to repair

Prepare to repair 

Before you start, it is important to sweep any debris or dust that could have built up. Once you have a clean subfloor, you can start to dampen any cracks or holes by brushing them with water. This prevents the filler from drying out too quickly and cracking.

Step 2: Repairing minor damage

Repairing minor damage 

You may find that there are larger cracks and holes in the floor. To combat any large cracks or holes, these should be filled with a mix of sand and cement mortar. Treat smaller cracks or holes with the self-levelling compound, then smooth with a trowel before leaving it to harden.  

Once the floor has set, you can prepare it for the full application of the compound by pouring a little water onto the floor and brushing it out to dampen the surface. Make sure that the area is damp, not flooded.

Step 3: Applying the compound

Applying the compound 

Mix the compound, then begin pouring it, starting in the corner furthest from the door. Spread it around the floor to a thickness of around 3mm with a plasterer’s trowel. Make sure that you’re working quickly but carefully, as the compound should set in around 15 minutes. After a few hours, you should be able to walk on the floor safely.

Frequently Asked Questions

How much does it cost to have a concrete floor levelled?

The cost of a concrete floor levelling project depends on the size of the project. The cost of materials should be around £17-20 for a 20kg bag of latex floor levelling compound. You may find that you need multiple bags to cover the surface of your room. A plasterer's trowel can cost anything between £11-18 depending on the brand and quality. 

If you are levelling the floor yourself, you need only to pay yourself in cups of tea or biscuits. However, if you plan on hiring a professional to complete the project, you should expect to pay around £10-12 per square metre. 

How thick can you use self-levelling concrete?

You should spread around 3mm worth of self-levelling compound on the floor to make it level. This will take into account any uneven bumps or cracks that may already be a part of the floor surface. 

Can you pour self-levelling concrete over existing concrete?

Yes, it is possible to level an existing concrete floor with a new layer of concrete. However, you must ensure that the existing concrete floor is prepared before pouring your new layer of concrete. If you fail to do so, the old layer could prevent the new one from bonding correctly. Adding a new level of concrete will increase the strength and longevity of a concrete floor. 

Can you use mortar to level out a floor?

No, mortars cannot be used to level out a floor. Once the thickness exceeds the recommended thickness by the manufacturer it can become unstable which will cause issues with any flooring that is laid on top. Even if the mortar is laid in layers, you shouldn’t use it as a levelling product as when the mortar cures it merges with the previous level and will become unstable.