Is this acceptable? - Tile Advice

[Jimmy2081]

We are in the process of tiling our kitchen. The kitchen is half floor boards which have been overboarded with 6mm cement boards

The tiles are 120x20 rectified plank tiles

The other half is a concrete floor

Total area 3.35m width by 6.87m length

Electric underfloor heating is also being installed throughout.

We've noticed the tiler in some areas of the floor primarily on the concrete side has used up to 30mm of tile adhesive!

We questioned this and were advised it is due to the floor not being level hence why less adhesive has been used on the cement board section but more adhesive is required to bring it level on the concrete side

Is this acceptable? If not what would be the correct method to address an uneven floor?

Our concern is that given 30mm adhesive has been used will the underfloor heating still heat the floor?

 

[shaney2000000]

Is the adhesive direct onto the wires.? usually would bring both floors
up to the same level then ufh fitted then a thin layer of levelling compound to cover wires then tile
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An even floor would usually be levelled with levelling compound before electr underfloor heating going down.

 

[J Sid]

Not normally practice or something I would do but something a lot of respectable companies do.
What adhesive was used and was an expansion joint put in at the intersection of two sub floors?

 

[Jimmy2081]

Is the adhesive direct onto the wires.? usually would bring both floors
up to the same level then ufh fitted then a thin layer of levelling compound to cover wires then tile
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An even floor would usually be levelled with levelling compound before electr underfloor heating going down.

The underfloor heating mat has been laid directly on the floor with adhesive on top using a 12mm notched trowel and he has also used adhesive directly on the tile using the trowel
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Not normally practice or something I would do but something a lot of respectable companies do.
What adhesive was used and was an expansion joint put in at the intersection of two sub floors?

Bal rapid flex one tile adhesive

The tiling started today, not much progress has been made as he was getting the levels right.

He hasn't mentioned anything with regards to an expansion joint
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Given the depth of the adhesive being 30mm will this affect the performance of the electric underfloor heating in any way?

 

[J K Tiling Cornwall]

30mm does seem to be one hell of a bed depth. Surely the tiler will be making more work for themselves trying to bed up to this level, doubt BAL would recommend it either. Would have been far better to have made up most of the difference with self levelling compound.

 

[Andy Allen]

any insulation boards ..??

 

[Jimmy2081]

We've got another tiler in who has started to level the floor. However we have some serious concerns with the appearance of the screend after 24 hours in some areas the floor has not dried and the fibres of the product have come up above the surface!

I have contacted Mapei and sent them over the pics attached who have advised it appears to that too much water has been added to the mix!

They cannot advise whether this has compromised the integrity of the screed

The product used was mapei renovation screed 3240

Does the screed look ok or does it need to be removed and started again?