"Levelling" a concrete floor

A couple of years ago we had an extension built. The screeding in one of the new rooms (5.5m x 3m) wasn't very good so I got the builder back to improve it with some "self-levelling" screed. I just checked it before laying some flooring and there are several areas that are 5-6mm low/high - too late to get the builder back so I need to sort it myself.
I realise that "self-levelling" screed is a misnomer and I've never enjoyed using the stuff before on small areas. Is there a "standard" way to tackle a job like this where there's no reference?
It looks like the high-spots were created when they latex'ed it; is it possible to sand-down the high spots?
Dave
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NoSpam wrote:

Me neither.

Best I can suggest is too lay a grid of strings, or battens, over the top and simply do it slowly bit by bit by eye and measurement.
Use levels laid on the grids to get the level precise.

Should be. Or simply chip it up and re-level.

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The Natural Philosopher wrote:

As it happens I have a similar problem on the near horizon - I have a floor where the screed for one half was laid at a later date to the other, and there's a fairly slight but discernable ridge at the junction, which will inevitably show through the intended vinyl floor covering.
If this was dry plaster on a wall, then I'd be getting out my orbital sander - but what's the tool to use for a concrete floor? Something on an angle grinder, maybe?
Thanks David
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A concrete planer will make your surface planar and plainer
http://www.hss.com/g/6401/Concrete_Planer_C_w_Blade.html
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Andy Hall wrote:

>

Thanks, but it'll make may wallet a bit more planar and plainer too, at 80 quid minimum hire! Since the room is a galley kitchen where the (transverse) "ridge" is less than a meter long, I think I may explore alternatives! Is there anything better than a brick/stone cutting disk I could use on the angle grinder to just 'tickle' the ridge a bit?
David
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Lobster wrote:

self-levelling floor screed? i used it in my house. worked fine.
dave cowell, germany
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You didn't mention the length of the problem.....
It might be possible to do it with an angle grinder and suitable blade.
What about solving the problem a different way and using a sheet of ply?
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Lobster wrote:

Latex screed can be sanded with an abrasive disc. Concrete probably not
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is
have a

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floor
orbital
Something on

not
The hire places will hire you a 'concrete grinder' that flatens floors
AWEM
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