Ask a question

The Bunnings Workshop community can help with your home improvement projects.

How to fix a large crack on a concrete slab?

Just Starting Out

How to fix a large crack on a concrete slab?



Bunnings Team Member
Bunnings Team Member

Re: How to fix a gap on a concrete floor? The location is under the cloth liner.

Welcome to the Bunnings Workshop community @tayeb. It's terrific to have you join us, and many thanks for your question about repairing concrete.

There appears to have been some subsidence in the area or a large tree root pushing up on the slab. Given that there is a height difference between the two sections of the broken slab, even if you were to fill the gap with something like expanding concrete of Sikaflex 11FC, that wouldn't really disguise the gap, but it might make it a little less noticeable.


The only real fix for the situation would be to enlist the services of a stabilisation company that would assess the slab and return it to level. The gap could then be filled. Be aware that this would likely be quite an expensive process.

Please let me know if you have any questions.


See something interesting? Give it the thumbs up!

Why join the Bunnings Workshop community?

Workshop is a friendly place to learn, get ideas and find inspiration for your home improvement projects