Polish concrete?

[Rickard_o]

I have a piece of concrete in the apartment that I will be building on.

I will be drilling into the concrete. Inserting plugs. Then wood will come on top and finally a screw through the wood and into the concrete.

I will need to make the surface of the concrete as even and straight as possible but still strong enough to be drilled into without cracking and crumbling.

As it stands now, it is a surface with some smaller holes and a difference in surface up to 3mm.

What is best to use to even out the surface and still keep it strong?

It is an elongated concrete strip with a width of 160mm and a length of about 4 meters.

 

[_bystrom_]

Repair mortar, like Ardex A45/A31, depending on the surface. A45 fills better but is a bit coarse. A31 is the opposite, fine but fills less. Sets quickly and usually does not crack. Pre-water the concrete thoroughly.

 

[Rickard_o]

Where should I ideally turn for repair purposes? Is it available at Bauhaus or do I need to go to a specialty store?

Is there some type of filler that also works?

Can Ardex be sanded?

Is a type of putty knife sufficient to apply the compound?

 

[_bystrom_]

Available at hardware stores. If they don't have Ardex, ask for something similar. A45 and A31 can be sanded, but it's tough. Preferably use real sandpaper in size 36 or coarser. At work, we use sanding discs for floor sanders even for hand sanding.
The consistency becomes like putty, and you use/apply it just like regular putty.

Otherwise, there is also fine gypsum putty, e.g., 828 (I believe the brand is Ardex there too). Finer surface, easier to sand. Also in powder form that you mix yourself.

 

[Rickard_o]

Sounds like a simple solution.

Probably easiest to go with a larger putty knife and a one-meter spirit level and a good deal of eyeballing Then it will probably turn out just fine.