Leveling tiled concrete floor

[0Floz0]

Hi,

I've had a read through the sticky but don't feel like leveling compound is my best option, or at least, its certainly not the cheapest.

I've got a conservatory floor with a concrete slab that is tiled on top. You can feel underfoot the levels are all over the place. We had to take a digger through it when doing the garden and it dropped down slightly but it was never great before.

I've put screws into the floor to assess the actual variance. There is a high spot in one corner and a low spot in the diagonally opposite corner. The max variance is 52mm. Though most of the variance elsewhere is about 20-30mm. If I were to do it in self leveling compound it'd be at least £400 in compound. I'm wary of putting more weight on it as that is what caused the drop. Are there any other options?

I was thinking maybe 25mm jablite on one side then where the variance is much smaller I could just do the leveling compound on that bit? Worried the jablite may be too thin at 25mm to be walking on. To reduce the high spots I was thinking of removing some tiles. That’ll be 14mm off or so in the high spot.

The plan for the finish is 12mm laminate. This will have 3mm sonic gold underlay.

Cheers

 

[dazlight]

What floor covering you going for ?

 

[0Floz0]

What floor covering you going for ?

Sorry. Just updated the initial post. Was tired when I posted yesterday. It’ll be 12mm laminate with 3mm underlay.

 

[dazlight]

Can you not take the tiles up if height is a problem ?

 

[0Floz0]

Can you not take the tiles up if height is a problem ?

I can for the really high spots but thats only going to give me 9mm for the tile and maybe another 3-4mm for the adhesive.

Its a rectangular room, about 2.7m x 5.1m. I've put 12 screws in 3 columns going across the room. Starting with the highest spot being 0mm as screw is straight into the floor (top right in below table). I've then got the measurements for each area of the floor. As you can see its pretty varied. The 3 columns is the shorter side and the 4 rows give you the longer side (5.1m). I'm hoping that makes sense.

20​	9​	0​
38​	30​	22​
32​	29​	25​
52​	36​	30​

Is it worth getting a concrete grinder and stripping tiles off. Then assume the area with 52 will need building up with some SLC or a sand/cement screed? I'm just wary of the transition between the bare concrete and the tiles.

 

[dazlight]

You used a laser for that ? But yes I’d be grinding down to get them closer before any compound

 

[0Floz0]

You used a laser for that ? But yes I’d be grinding down to get them closer before any compound

Checked it with a laser, but basically did the screw distances so I could run a 6ft level between them, then adjusted the screws to get them level (using the 0 as the initial reference point) and then measured the height of the screw from the floor for the deviation.

Are there alternatives? I guess if it was wood I'd run some tapered battens across, screw those into the concrete and then put osb boards over it? That'd leave gaps with no ventilation though...

How would you do it?

 

[dazlight]

I split the room in to section of 3 or 4. Then use plywood strips to get my levels then put the screed in each section over a week. A lot of time to get it right.

 

[0Floz0]

I split the room in to section of 3 or 4. Then use plywood strips to get my levels then put the screed in each section over a week. A lot of time to get it right.

How do you use the plywood strips to get your levels?

I think im going to take out the high spots. Rather than a grinder I think I’ll cut into it with a big cutting disc. Then knock bits out between the cut lines. Then will build up the really low spot and SLC the whole floor.