How flat do I need to be for vinyl?

[thomp1983]

Hi all,

Self levelled our utility room before we went on holiday.

Now we're back I've noticed there are a few ridges still, there not huge but do leave a roughly 1 to 2mm gap below if a spirit level is placed on them, I've tried to picture them as best I can looking across them at floor level

I've also took a couple of pictures of the vinyl were going to use, it's about 3.5mm thick.

Are these ridges going to show through the vinyl once it's walked on and I need to apply more self levelling between them/grind down the ridges or do you think it will be ok?

Thanks
Chris

 

[conny]

I once made the mistake of putting a small piece of thick lino over some Riven slabs in a small vestibule think it would be ok.
Within about 3 weeks you could feel/see the bumps and dips and eventually splits/holes developed so had to rip it up.
Thankfully it was an off-cut from the kitchen so money wasn't wasted, just my time.

I would fill in the hollows first. Let it set and check the level. If there are any remaining bumps, then lightly sand them down.

 

[dazlight]

sand the ridges down

 

[IJWS15]

What is the floor underneath the SLC?

Not by any chance timber planks that are still moving?

 

[thomp1983]

No it's concrete thta wasn't finished the best so has a few ridges through it

 

[dazlight]

Maybe give it another 5mm coat