Has all my Laitance been removed?? - Tile Advice

[Ashah12]

So my liquid anyhydrate screed was laid in December, the laitance was removed mechanically by a sanding machine with diamond cutter 5 days later. I'm on the verge of getting the floor tiled in the next week or so. I commissioned the ufh a few weeks ago. Now I'm getting cold feet thinking the laitance hasn't fully been removed. I've attached pics for all you pros to see and hopefully reassure me that everything is fine and I'm overthinking. The floor does need a good sweep and vac but my question is do I need to get the guy back to sand it again?? It cost me £200 to get it sanded in the first instance.

 

[Dave]

Yep , looks fine.

 

[Ashah12]

Yep , looks fine.

Thanks mate! I made the mistake of not hoovering all the removed laitance immediately and left it so I was worried the laitance had bonded back to the screed. Is that possible?

 

[Dave]

Thanks mate! I made the mistake of not hoovering all the removed laitance immediately and left it so I was worried the laitance had bonded back to the screed. Is that possible?

Nah. Just hoover it up. What method are you using to tile it ?

 

[Ashah12]

Nah. Just hoover it up. What method are you using to tile it ?

Ideally I would like to use anhyfix to fix the ditra mat but finding it hard to source the product. Ontop of the ditra itll be setaflex to fit the tile. If I cant get hold of the anhyfix what would the next best method?
You're help and advice is very appreciated.

 

[Dave]

Ideally I would like to use anhyfix to fix the ditra mat but finding it hard to source the product. Ontop of the ditra itll be setaflex to fit the tile. If I cant get hold of the anhyfix what would the next best method?
You're help and advice is very appreciated.

Might be wrong but not sure anhyfix is suitable for ditra. Best check with schluter. It’s not an adhesive I’ve used.

 

[Ashah12]

Might be wrong but not sure anhyfix is suitable for ditra. Best check with schluter. It’s not an adhesive I’ve used.

What would be your preferred method? What adhesive would you use with Ditra matting and porcelain tiles? And what primer?

Thanks

 

[Dave]

What would be your preferred method? What adhesive would you use with Ditra matting and porcelain tiles? And what primer?

Thanks

I’ve done quite a lot of them now. I prime with acrylic primer 4 to 5 coats following directions for anhydrite screed. Fix matting with spf rapid and same for tiles. I use weber products. The screed must be dry and fully commissioned.

 

[Ashah12]

I’ve done quite a lot of them now. I prime with acrylic primer 4 to 5 coats following directions for anhydrite screed. Fix matting with spf rapid and same for tiles. I use weber products. The screed must be dry and fully commissioned.

4 to 5 coats?? What dilution ratio do you use per coat? I'm getting alot of conflicting information in regards to the type of adhesive used with anyhydrate screed. Some say cement based adhesive is a no no as can it can have issues with bonding to the screed and anhyfix (gypsum based) is the way to go and some say there's nothing wrong with a cement based adhesive. I just dont want to make a very expensive mistake.

 

[Dave]

4 to 5 coats?? What dilution ratio do you use per coat? I'm getting alot of conflicting information in regards to the type of adhesive used with anyhydrate screed. Some say cement based adhesive is a no no as can it can have issues with bonding to the screed and anhyfix (gypsum based) is the way to go and some say there's nothing wrong with a cement based adhesive. I just dont want to make a very expensive mistake.

I use a 4:1 ratio and not had a single issue with bonding . Yes gypsum adhesive can be used to adhere the tiles but like i said , not sure schluter uk advise to use it with Ditra.

 

[Ashah12]

I use a 4:1 ratio and not had a single issue with bonding . Yes gypsum adhesive can be used to adhere the tiles but like i said , not sure schluter uk advise to use it with Ditra.

Is that 4 parts water to 1 part primer or the other way around? And do you use the same ratio for every coat? Thanks

 

[Dave]

Is that 4 parts water to 1 part primer or the other way around? And do you use the same ratio for every coat? Thanks

Yes. 4 water to 1 acrylic primer or whatever the primer says. Sone have different ratio. 4:1 is one i use PR360.

 

[Ashah12]

Yes. 4 water to 1 acrylic primer or whatever the primer says. Sone have different ratio. 4:1 is one i use PR360.

Thanks mate!

 

[Ashah12]

Yes. 4 water to 1 acrylic primer or whatever the primer says. Sone have different ratio. 4:1 is one i use PR360.

Thanks mate

 

[Ashah12]

Just to update I've hoovered the whole floor and I've noticed theres areas of lighter patches. Could this be laitance stuck to floor or is this normal?