Child Item

How to level a concrete floor?

Hey Bunnings fam, I’m doing a kitchen renovation and have noticed there’s a crack in the slab and it drops 15mm over a 2 to 2.5m span. In the pic it drops away from the levels on the ground to the far corner.

Will the self levelling cement fill up a 15mm difference in height..? And how many bags would you think I need..! Or do I have to go down another route to fix this..🤔

Find more posts tagged with

Tools and Materials

Repairing

Renovation

Flooring

Accepted answers

All comments

JacobZ

Hi @DxMxGxD,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I'd suggest using Lanko 20kg 173 Floor Leveller. This can be used in layers up to 25mm thick so there's no issue there. One bag will cover approximately 12 square meters at 1mm thick.

Using your measurements and the level as a scale, I would suggest the most you would need to be safe is 15 bags.

They can always be returned if unused, so it might be worth assuming you'll need more and returning it if you don't end up needing it.

Let me know if you have any further questions.

Jacob

DxMxGxD

Thx Jacob for the reply, I went and bought a crossline laser from Bunnings and have figured out the exact measurements of the floor slope (see pic).

In my revised measurements I’m thinking I’ll only need 10 bags at most, but would like your opinion on this as I’m not mathematically correct at the best of times..🤦🏼‍♂️

I’ve seen a few vids of people fixing height markers to the floor so you can see how much of the floor leveller to put in, which I thought is a fantastic idea..!

And I’ve heard that adding an extra 500ml of water to each batch

will obviously make it more runny and self level easier, but just add extra time in drying process. Do you think this is a viable idea or it might compromise the product once dry..?

JacobZ

Hi @DxMxGxD,

Looking at your heights it's hard to get a perfect idea of what you'll require but 10 bags should be more than enough. Just remember that you can always return bags that are unused so don't mix it all in one go, start with 2-3 and add more if required.

The crossline laser is going to be fantastic for this purpose and will help you transfer lines on to your walls to set your height for the finished floor level.

You can do this by working out how high the horizontal line is in comparison to the base of the laser. For example, the horizontal line on my laser level is 115mm above its base.

Once you're aware of this measurement, set the laser on the highest point of the concrete floor. The horizontal line on the wall will give you a level mark that you can measure down from to put a finished floor height. This will definitely make the job of working out when you've used enough leveller. Make sure you ease up to this point, it is easy to add material, it's not so easy to remove it.

I wouldn't advise exceeding the liquid ratio that the manufacturer has indicated. It may work, but it's best to follow their mixing ratios as that is what their research and development teams have used to define the technical specifications of the product. You're probably going to find that the amount of water they've advised will make it runnier than you think. Self-levelling compounds are almost liquid when they are mixed, this is how they can level themselves without much assistance.

Let me know if you have any further questions along the way, I'd be happy to assist further if required.

Jacob

Child Item