How to prepare concrete for laying floorboards

[knockerchoppington]

Hi
I'm about to install some 6mm insulation and floorboards over a concrete floor. There are a very few high points in the concrete (20cms wide max) that need leveling down by a maximum of 1cm. What are the ideal tools and methods for doing this?

Thanks in advance

 

[woodfloordesigns]

If the floor is out by 1 cm across an area of 20cms that is quite bad. It is possibly a job for a proffessional as floor grinding requires tools that are not available to hire as far as i am aware. Also that is quite a lot to be brought up with a leveling compound. The underlay that you are using will not take much of the uneveness (is that a word?)out . The surface to be laid on should be no more than 2mm out over a span of 1metre.

 

[mointainwalker]

Is this 6 mm for sound or thermal insualtion ?

 

[knockerchoppington]

Hi and thanks for the replies. The problem I have is that my builder overcompensated when adding some levelling compound in a particular area. What I'd like to know is suggestions for removing some of this so that I can reapply properly. I was thinking of using an angle grinder to score lines and a masonry chisel to chip out the bits. I know it's a bit bish bosh but as it's such a small area I feel this is what it demands

 

[mointainwalker]

I don't know how hard self-levelling compound is, but your angle-grinder (230 mm ?) idea should certainly work.

I uncovered some large rocks when laying my floor and needed to take about 30 mm off the top. I sliced a crossed pattern of grooves and then knocked the little squares out with my SDS and a chisel bit. Sheared reasonably cleanly.

Would guess you will kick up a lot of dust though. Need good ventilation and cover up/remove furniture

 

[knockerchoppington]

Is this 6 mm for sound or thermal insualtion ?

it's for thermal insulation

 

[mointainwalker]

You haven't given any details of where this room is in the house or its purpose, so this is just a general comment.

A layer of 6 mm of insulation is so little, that although it should make a tiny amount of difference, you are not going to notice it.

 

[woodfloordesigns]

If the high spots are latex and not sand/cement screed then your angle grinder should level small areas successfully. Try smoothing before removing. But I agree about the dust.

 

[knockerchoppington]

You haven't given any details of where this room is in the house or its purpose, so this is just a general comment.

A layer of 6 mm of insulation is so little, that although it should make a tiny amount of difference, you are not going to notice it.

It's going on the lower ground floor level of a maisonette. I can't afford to lay underfloor heating or lose any ceiling height so it's really just to help lay the boards and take a slight edge of the cold. I'm using Timbermate Excel