Porcelain to anhydrite screed whats your favorite method? - Tile Advice

[carfarmer]

Hi i'm self building my own barn conversion and have a anhydrite screed and underfloor heating.
Screed was laid 8 months ago and latence removed about 5 months ago, the heating cycled during the winter but off now as its 'summer'.
I dont have any way of testing if its dryed out but have had a dehumidifyer reading 65rh for the las month while plastering the walls.

The largest area is openplan layout 8meters x 6meters
Porceline tiles 900x225 to be laid in herrin bone (the wifes idea to keep me on my toes).
Note: the screed runs through the whole house 160sqM without any expansion joints and i want to tile the lot.

I assumed i would be laying the 8mm tiles on 4mm of TM anhydfix adhesive and have set the door frames to leave a 10mm gap below the doors, as this is the spec for the MVHR system, to the finish floor height.
Then someone said i should put in expansion joints and use anti crack membrane.

A few of you have differing opinions though, including matting and cement based on top which would increase the thickness of the finish height. I know i can trim the doors down by 6mm but the front door could be an issue?

Where if any should i put expansion joints in the tiles.

Thanks for your insights

Martin

 

[Ajax123]

You should technically be putting movement joints in door thresholds, between independently controlled heating zones and to split the tile face into 40m2 bays with maximum 8m bay length... uncoupling not necessary for porcelain. I'd probably run a sander over it lightly to get rid if plaster snots etc and stuck tiles down with anhyfix as suggested.

 

[carfarmer]

You should technically be putting movement joints in door thresholds, between independently controlled heating zones and to split the tile face into 40m2 bays with maximum 8m bay length... uncoupling not necessary for porcelain. I'd probably run a sander over it lightly to get rid if plaster snots etc and stuck tiles down with anhyfix as suggested.

Thats reasuring thanks Ajax123,

Ive been scraping up the snots with a 10" drywall blade and then hoovering, they seem to pull off cleanly with the advantage of wearing the new blade in.

The bathrooms/wetrooms are sand/cement mix so they have an expansion joint, but realise now maybe joints should have been put in the screeding too.

Should the screeder mentioned this? as i sadly no longer have much faith in my architect

Does an expansion joint in the tiles have to be staight or can it follow the herrin bone pattern?
You can laugh i dont mind, i tend to think outside the box so its normal.

 

[Ajax123]

Thats reasuring thanks Ajax123,

Ive been scraping up the snots with a 10" drywall blade and then hoovering, they seem to pull off cleanly with the advantage of wearing the new blade in.

The bathrooms/wetrooms are sand/cement mix so they have an expansion joint, but realise now maybe joints should have been put in the screeding too.

Should the screeder mentioned this? as i sadly no longer have much faith in my architect

Does an expansion joint in the tiles have to be staight or can it follow the herrin bone pattern?
You can laugh i dont mind, i tend to think outside the box so its normal.

Technically speaking joint should follow a straight line. The screeder will have put the screed in according to the designers spec I'd assume so really it should be the architect that designs any joint pattern. I haven't come across herringbone shaped joints but assuming each side of the joint is the same length the restraint would be cancelled out and it would act as if utsxaxstraight line.

 

[carfarmer]

Technically speaking joint should follow a straight line. The screeder will have put the screed in according to the designers spec I'd assume so really it should be the architect that designs any joint pattern. I haven't come across herringbone shaped joints but assuming each side of the joint is the same length the restraint would be cancelled out and it would act as if utsxaxstraight line.

Nothing on architects plans and screeder didnt nention anything.
I will see how it works out hopefully get some pictures while working on it.