Using SLC to bring existing floor height to the height of extension floor. - Tile Advice

[AP tiler]

Hi All.
Im a tiler based in Cheltenham and new to the forum.
Im tiling about 86m2 of planks next week and need to level the floor before hand(long weekend job). The problem that I have is that in the existing part of the house, the floor is about 20/25mm lower than the extension concrete floor. I'm using leveller to bring the whole downstairs to the same height. Does anyone have any idea on how the accuratley bring the existing floor height up to the extension floor height to make it flat accurately? Iv'e attached a picture of the floor plan. The blue areas are the extension parts of the floor and the yellow, the exisisting.
Thanks in advance,
Alex.

 

[Old Mod]

Find the highest point of the new concrete floor and measure 1m up from there and mark a datum on the walls around the the new areas.
Then using a laser or water level, transfer that datum around the whole ground floor.
You can then use that datum in the other rooms to bring them up to 1m below your datum.

 

[AP tiler]

Hi, Thanks for the response.
Ahh good idea, I guess then do several pours and check the height against the datum each time the pour has dried?
Cheers.

 

[Old Mod]

Hi, Thanks for the response.
Ahh good idea, I guess then do several pours and check the height against the datum each time the pour has dried?
Cheers.

Exactly that.
You can measure off your datum and put markers on the floor so you know how high to come approx.
Stick joiner packers on floor with a glue gun or silicone to give you a gauge to go to.

 

[AP tiler]

Perfect
Great idea mate thanks for the help, will be trying this meathod out. really appreciate it.

 

[Old Mod]

No problem mate, that’s why we’re here, we all help each other.

 

[Time's Ran Out]

Some more than others

 

[Albert]

86m at 25mm = £££££ i think i would be tempted to lay
backer board of some sort first

 

[GoneGuy]

Same as @Albert, would be a bit cheaper/quicker

 

[AP tiler]

25mm is the worst part, parts are much lower. its going over retro fit wet underfloor heating mats, hence the use of leveller.

 

[Bill]

25mm is the worst part, parts are much lower. its going over retro fit wet underfloor heating mats, hence the use of leveller.

So are you not putting insulation boards on top of the floor first?

 

[Flintstone]

What’s the underfloor heating system that your proposing to level over ?

 

[Old Mod]

So are you not putting insulation boards on top of the floor first?

What’s the underfloor heating system that your proposing to level over ?

Do you not think he may mean polypipe or similar?
As it’s a retro fit wet ufh system?

 

[Bill]

Do you not think he may mean polypipe or similar?
As it’s a retro fit wet ufh system?

I thought retro fit mats meant after the solid floor was in?

 

[Old Mod]

I thought retro fit mats meant after the solid floor was in?

The way I interrupt the situation is that the original house is 25mm lower because there’s ufh in the new screed and a retro fit system will be fitted to the existing and then levelled over to bring it up to one level.
Personally I’ll always level over any polypipe style ufh anyway, so I suppose that’s how I’d want to interrupt it.