Old question but still confused....

[thickbed]

Just make sure the screed is dry enough to tile to and get the laitance removed before you do anything else

 

[thickbed]

Just make sure the screed is dry enough to tile to and get the laitance removed before you do anything else

 

[JimboD]

Arh yes, "laitance". I noticed the dusty film when the screed was first poured (didnt know the technical name) but over the past few months had assumed it had all come away with all the coming and goings, sweeping and hoovering. Will check tomorrow if its still there. Hopefully wont need to attack it with a rotary sander but knowing my luck....Better to check now though and sand if necessary, than have 5k of tiles lifting in a years time!

NB: The screed came from SouthernScreed and on their website they show a video of someone sweeping the laitance off with a broom!

So many steps - laitance removal - UFH cycle - moisture level - sealing - possible membrane - adhesive choice - tile sealing - expansion gaps etc etc etc. ALL of which many DIYers will have overlooked or got wrong

 

[Albert]

Just looked into membranes on Impish's suggestion. A few rolls of durabase seems the best bet but adds 3mm to the depth. Hmmm, need to do come careful measurements tomorrow as i think 3mm membrane +4mm adhesive + 12mm tile might be too high for then being able to run the tiles flush into the bifold door edging strip.

Thanks everyone for the speedy replies!

Ball and Mapei do 1mm mats

 

[JimboD]

1mm would help. Seems straight forward enough to install from Mapai YouTube video. Just adds more time and cost.

So given main room is 10x6m is the decoupling membrane essential when using 12mm limestone and UFH.

 

[Bill]

1mm would help. Seems straight forward enough to install from Mapai YouTube video. Just adds more time and cost.

So given main room is 10x6m is the decoupling membrane essential when using 12mm limestone and UFH.

natural stone and ufh = a crack mat.

bal, mapei, tilemaster & idrobuild tex all do a 1mm mat.

 

[JimboD]

thanks!

 

[Unused Account 1]

Not many big areas (screeds)are level so have to find the high point and come off that ,if you want it looking the nuts,you have to back butter porcelain anyhow ,whatever you decide ,screed the floor and put 6mm on back of the tile ,big area for diy,expensive if goes wrong

 

[Waluigi]

After all the crap you’ve been through and considering the issues you have with heights, I’d be putting LVT down especially as I’m sure you said you were going for planks.

Just my honest opinion......

 

[EdMac]

you have to back butter porcelain anyhow ,whatever you decide ,screed the floor and put 6mm on back of the tile

I've got 59cmx59cm porcelain tiles. Floor is flat enough, maybe the odd minor discrepancy here and there but nothing major. Tile shop said will be fine with a 20mm round notch trowel (has a depth of 15mm).

I was planning on back buttering the tiles with the flat edge of the trowel - are you suggesting to use a smaller notch trowel to add to back of tile or will I be OK with my buttering plan and is 6mm a general target or too much for my smaller tile?

If I have a total adhesive depth of c8 to 10mm and as near to 100% coverage as possible the odd minor floor discrepancy (2mm her and there) should not be an issue?

 

[Unused Account 1]

12mm on the floor 3 to 4mm on the back should do nicely ,if the floor is that flat

 

[Flintstone]

Your trying to run before you can walk here. What is the screed made of, have you got a hygrometer to test it and have you got floor sanding equipment? It's a none starter if you can't answer those with a yes. A membrane isn't an option if you fancy it, it's a must. Also 10mm trowel is too small, it's hard work trying to get coverage with that size trowel. Why are you getting a professional out if you are doing the job your self ?

 

[Just Rizzle]

the mapie anti fracture membrane is 1 mm thick and flat put down with a 3mm trowel 2mm build up if hight a problem or even tilemasters anti fracture matting

 

[Bond]

You say , main room is 60 square metres, UFH and 12mm limestone, without expansion joints or anti fracture matting, ( not a good plan at all ) .