Setting Out Biscuits screed (dry) SBR??...

[Deleted member 53943]

Evening folks.
I’ll get straight to the point. Been to look at a job. Dining area / kitchen. Roughly 45m2
The contractor previous have installed underfloor heating and screeded it with a biscuit mix dry (7-1). The floor to me wants self levelling before anyone starts, it’s not bad for level but very bitty. Sweeping a brush creates a dust.. the client has said not to SBR it but if they want me to tile I’m insisting it’s done. Anyone every come across this and have any other ideas?.. (spray an SBR?)
Any help appreciated
H

 

[judge]

Hover the screed and prime sbr/water 1-4 ratio.give it a second prime if it still absorbs .if it's really crumbly (bitty) it's probably been mixed too dry .why doesn't the customer want you to prime the screed ???

 

[Deleted member 53943]

Hover the screed and prime sbr/water 1-4 ratio.give it a second prime if it still absorbs .if it's really crumbly (bitty) it's probably been mixed too dry .why doesn't the customer want you to prime the screed ???

morning,
The customer (she) told me it had already been done and sealed via building contractor’s but I’m going to insist if she wants me to do it. I’m going to SBR the floor prior to any works done. Don’t want any problems down the line. I just wanted to see if anyone had come across this biscuit screed before. 99% of my work if concrete or tile backer board prior to tiles.

 

[judge]

From what I've just read up on biscuit screeds you can't tile directly to them.theyre not strong enough.is this on a suspended floor ?

 

[Deleted member 53943]

No mate it’s a solid floor, i put the post up to see if anyone had come across a biscuit screed mix, the floor it self is sound enough (levels wise). Alarm bells just started to ring when she said not to SBR the floor prior to me self levelling it.

 

[judge]

Ask the customer to give you a reason as to why the floor shouldn't need sbr seal(prime).
7-1 is a really week mix and from what I've read they aren't disigned for tiling.4-1 is normal sand/cement.

 

[Dumbo]

To be honest if had the customer dictating to me how to do the job i would just leave it as it will end in tears
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Also you are getting a warning on how the customer is going to be on the rest of the job

 

[Ajax123]

Walk away. 7:1 uncompacted biscuit screed will fall to bits with heating. The tiles WILL fail.

 

[Cris]

7-1 screed mix is very poor base to tile on. use a membrane or walkaway coz tiles will deffo fail