18mm cement board UHF - Tile Advice

[Flintstone]

Can somebody answer me if the boards are gypsum or not?

 

[wayne]

I tiled one over a year ago with flexi addy straight onto the boards after priming. Been back recently and the job is still spot on.

 

[Dumbo]

Can somebody answer me if the boards are gypsum or not?

I was told they are gypsum . But something called spent gypsum so wouldn't react . I may of misunderstood what I was told though .

 

[shongu]

I've looked into it and its material called dry screed. The main component is calcium sulfate which is gypsum. So priming is key. Water absobsion is 30% without priming.

 

[Old Mod]

Yes these systems are loose lay, they’re supposed to level floor first and then glue board edges together as they’re laid, creating one large sheet.
Done correctly, they don’t move, the weight is colossal.
Prime the entire area thoroughly, applying at least two coats perpendicular to each other, use a grit based primer on plastic areas. (Prime & grip or similar)
Charge the system to 5-6 bar cold and latex with 5mm covering above pipes.
This causes pipe expansion, so when the system is discharged they contract leaving enough room for the pies to expand and contract when in use.
Minimising the risk of movement.
Anti fracture mat, it’s stone, it needs one.
A 1mm mat would be sufficient, no need for Ditra, although it will offer a higher level of protection.
Tile
and correct ufh commission, is paramount.

 

[Time's Ran Out]

You see you do learn things on here!