How to repair concrete slab for tiling?

nieldy

We had a water leak recently and the plumbers needed to smash into quite a few tiles and through the concrete slab in our back veranda area. We have got new tiles ready for the tiler to lay, but first need to re-concrete the two holes made (see photos below). As you can see, one is pretty big, and the side will also need to be concreted flush. The other is fairly small.

I'm trying to work out if this is something fairly easy that I can do myself, or if I get someone to fix it. I've only ever concreted the base of a letterbox before, so I'm pretty inexperienced. The new tiles are quite expensive, and I don't want to risk making a mistake with the foundation if it's not an easy job.

Could someone give me any guidance on:
* How hard is this DIY job (and how easy is it to mess it up)
* If I do it myself, any tips for the process (i.e. do I need to remove loose rocks first, should I backfill some of the large area first, etc.)
* Roughly how much quantity of concrete does it look like I might need (based on image)

Cheers,


Stephen

EricL

Hello @nieldy

Thank you for sharing your question about your concrete slab repair. I feel that this project is just at the edge of D.I.Y territory. Filling the gap with concrete is the easy part, getting the surface to be perfectly level with the former level of the concrete base is tricky. It has to be perfectly level so that when you install the tiles along with the tile adhesive it will need to perfectly line up with the existing tiles. Because it is right next to your aluminium sliding door frame any errors in levelling will be glaringly obvious as you will see it matched up against the straight edge of the aluminium frame. The same conditions apply to the smaller hole as well.

However, if you were to give this a go, the basic steps to repair would be to remove all the loose stones and sand in the gap. A primer will need to be applied to the broken concrete surface. I recommend installing a guideline to indicate the level of the concrete base. Once everything is prepared the concrete can then be put in. The concrete will then need to be levelled and finished with various concrete tools.

I vote getting a professional to do this repair or a handy person with experience with concrete repair.

Let me call on our experienced members @Nailbag, @Dave-1 and @DIY4Knuckleheds for their recommendations.

If you need further assistance, please let us know.

Eric