How to fill gap between external wall and concrete?

[Rohitash]

I am noticing a gap between external wall and concrete floor, has increased from a centimetre to about an inch in last 12 months, rain water sneak in, insects crawling, pl  suggest as how to fix.

[JacobZ]

Hi @Rohitash,

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

Is it possible to get some photos of the issue? This will help our members narrow down an answer that will work in your specific circumstance.

If the gap is similar to the one in How to fill gap between side concrete and slab, you could follow my advice to stuff Ableflex into the gap and cover with Sikaflex Pro+.

You might like to check out How To Silicone a Gap for a guide on how to apply the sealant.

Let me know if you need a hand uploading images, I am more than happy to help.

Jacob

[Rohitash]

Gap between wall and floor concrete increasing slowlyGap between wall and floor concrete

[EricL]

Hello @Rohitash 

Thank you for posting those photos of your concrete walkway and your wall. Let me tag my team-mate @JacobZ to make him aware of the photos. Unfortunately, I'm afraid the gap is now too big to be repaired with Sikaflex. Although some parts might be able to be covered up the large portions are just too big.

I believe rainwater has entered through the gap or elsewhere and has run under the slab causing it to sink and move away from the wall. This water ingress must be addressed first as any repairs carried out will prove useless. 

It might be possible to fill the gap with new concrete, however, that means that the slab will remain on a slant. Plus, there is no guarantee that the slab will remain stable with this type of fix. 

I'm currently not aware of a D.I.Y product that can uniformly lift the slab back into place. I suggest engaging the services of a concrete slab repair specialist, The specialists will be able to lift the slab using polyurethane or a similar product. 

If you have any other questions we can help with, please let us know.

Eric