Tech Info required - Tile Advice

[On one]

Apologies for the scant information that I have at the moment,but I need a bit of technical information before going to have a site visit with a customer tomorrow morning.
The customer has an kitchen floor which is half concrete and the other half will be a suspended timber joist/chipboard floor(when completed)
Obviously the chipboard will have to be overboarded and an expansion joint placed over the different substrate joint,but should I overboard the whole kitchen floor(is it possible to drill,plug and screw Hardi into concrete?)
The tiles are going to be 20mm multi sized Limestone

 

[Alan.P]

Yes you can fit Hardi to concrete, why don't you factor in for Plywood instead of chipboard and add hardi over the lot ? Allow for an expansion joint where the two meet, how big is the floor.

 

[White Room]

Screwing Hardie to the screed floor is not somethink I've tried, what about self leveling....

 

[Andy Tiler]

Can't see y not? But if it were me I'd screed up the concrete side with Tilemaster levelflex! It's ready for tiling after a couple of hours!!

 

[On one]

Yes you can fit Hardi to concrete, why don't you factor in for Plywood instead of chipboard and add hardi over the lot ? Allow for an expansion joint where the two meet, how big is the floor.

Not sure, not seen it yet.

 

[charlie1]

As for the 20 mm multi sized limestone, I assume the expansion joint wont be straight forward??

 

[On one]

Can't see y not? But if it were me I'd screed up the concrete side with Tilemaster levelflex! It's ready for tiling after a couple of hours!! 

Don't know if the existing concrete floor needs SLC yet. My main query was do I need to bridge the different substrates with Hardi or can I overboard the chipboard floor and butt the Hardi up against the concrete floor with the expansion joint over the top?

 

[On one]

As for the 20 mm multi sized limestone, I assume the expansion joint wont be straight forward??

They can like it or lump it,it's got to have a one!

 

[Andy Tiler]

Don't know if the existing concrete floor needs SLC yet. My main query was do I need to bridge the different substrates with Hardi or can I overboard the chipboard floor and butt the Hardi up against the concrete floor with the expansion joint over the top?

Yes butt the hardi up to the concrete and put your joint on top! Don't bridge it!!

 

[On one]

Yes butt the hardi up to the concrete and put your joint on top! Don't bridge it!! 

 

[judge]

even if you hardi over the lot you still have two substrates underneath which will move seperately.I cant see the hardi solving the movement issue imo

 

[charlie1]

even if you hardi over the lot you still have two substrates underneath which will move seperately.I cant see the hardi solving the movement issue imo

Expansion joint will allow two substrates to move separately

 

[Perry]

Why would you want to plug and screw the hardi ?

 

[On one]

Why would you want to plug and screw the hardi ?

Just to stabilise the different substrates, not to do away with the expansion joint.

 

[Perry]

Just to stabilise the different substrates, not to do away with the expansion joint.

I have never used it but I would thought one would stick it with tile adhesive to a solid floor. even on a wooden floor ?