# Forum Home Renovation Concreting  Help repairing concreting work

## ddixon

So I've been reason these forums for quite a while and have learnt so much along the way. Thankfully I've generally always managed to get by without ever actually needing to ask any questions. But I definitely need some advice now...  
Had a slab poured for a shed recently - 14m x7m. I was pretty happy with the end result except the concreters got one of the u-brackets in the wrong spot. No problem though apparently as they said they'd come back, cut it out, reposition and re-concrete. Picture below is of the end result which I'm less than happy with. I've spoken with them and unfortunately paid cash on the day so am not sure I'm going to get much joy in getting them to fix it. So I'm going to tackle this myself.   
So my question is can I simply grind the concrete back a fair way and use something like mortar to smooth and cover up the area, I'd like it to be a similar colour and finish to the rest of the slab. If not, what would you suggest I do to fix the problem?? I'd also like to round off the edge which wasn't done and attempt to fill the cuts left behind.   
Thanks very much for your help in advance! Cheers

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## ringtail

Looks like it's been rained on ? How far is the steel embedded into the concrete ? Is the new concrete pinned to the rest of the slab ? To lay new concrete you will need 50 mm minimum depth or it will just crumble away. You could use a epoxy type leveling compound like lanko. The colour may be slightly different but it can used down to a feather edge thickness. Get a cup grinder wheel for the angle grinder and take the area down 3 - 5 mm first. That would be easiest I think. Round off the edge with the cup grinder too.

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## ddixon

Thanks very much ringtail. It did rain on the day they patched the spot and I was told they’d be pinning the old concrete to the new so hopefully that’s been done, guess time will tell! The steel is set approx. 70mm into the slab. 
The shed will actually serve two purposes, the end nearest the house will be a granny flat for visitors and we intend to grind and polish that end (which will require a whole separate set of questions I’m sure!). The end where the patch is will be a general workshop and storage area. I’m a bit of a perfectionist so the look of the patch really bothers me but I’d been thinking about painting the floor anyway, most likely with the water based White Knight concrete paint. I know it’s not the most durable thing going around but the price is right and I can reapply fairly simply in future if needed. 
Question is if I use an epoxy self leveller like lanko, will this affect the plan to paint the concrete with water based paving paint in the near future? 
Another question is, what can I use to fill the gaps in the side of the repaired area and around other brackets (see pics below)? Note the plans required the end u-brackets to be placed hard against the end of the slab which has resulted in a few more gaps… 
Thanks again

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## johnc

You may get an acceptable finish with the cup grinder just bringing it level although it would be more of an exposed aggregate finish. Otherwise what Ringtail said will fix the issue, colour will be different but in the end it is just a shed.

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## ringtail

Not sure if you can paint over lanko - can't see why not. Have a google. With the honeycombing on the side I would make a mix of mortar and then chuck a decent amount of bondcrete in the mix. Then keep adding mortar until its nice and workable without being sloppy. You only need a little batch. 
With the steel, what sort of brackets are they ? Normally a post stirrup has about 300 mm embedded ( into a post hole) for tie down of the structure.

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## ddixon

Thanks heaps, I'll hit the area with cup grinder and try the Lanko to see how it comes up over the weekend.  
The brackets are set about 170mm into the concrete and there's a bored 300m wide by 600m deep footing underneath each bracket. The 4 corner brackets are set about 250mm into the concrete.  
Cheers again, will post how it goes.

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