Sbr bonding slurry ratios help

Bowlzi

New Member
Hi, i need to buy enough sbr and cement for a slurry under a very thin sand cement screed so it is bonded. 18m2. Its replacing an old now removed screed.
Whats the ratio and quantity needed.
Thanks
Tried searching but search engine will not search on sbr for some reason.
 

malc

TPF Special Forces
Is that 5ltr to a 25kg bag cement? 1:1
I wasn't sure that would cover 18m2?
Just confirming i have understood correctly.
Thanks

NO. do not mix portland cement with sbr. the cement will dry before the screed and adhesion will fail.

flood the oversite, apply neat sbr a couple of min. just before you tip the screed on to the oversite.
sbr needs to be added to the screed mix.
brush the screed mix into the prep oversite. the sbr needs to be wet to accept the screed .
 

Bowlzi

New Member
NO. do not mix portland cement with sbr. the cement will dry before the screed and adhesion will fail.

flood the oversite, apply neat sbr a couple of min. just before you tip the screed on to the oversite.
sbr needs to be added to the screed mix.
brush the screed mix into the prep oversite. the sbr needs to be wet to accept the screed .
Thanks. Back of sika and febond say 1:1 or 2 sbr to opc. And creamy mix. They do state as you say not to let it dry ( 20mins max) before laying screed on top. assume working in smaller areas?
Thanks
 

malc

TPF Special Forces
Thanks. Back of sika and febond say 1:1 or 2 sbr to opc. And creamy mix. They do state as you say not to let it dry ( 20mins max) before laying screed on top. assume working in smaller areas?
Thanks

what it states on the back of the pots is an old spec. that method has been out of date in uk for around 25 years.
have a few mixes of screed ready with sbr added to the mix.
brush the sbr onto the oversite, and spread the screed mix thinly, onto the oversite. you have then built up a key, and you can start to lay your screed.
 
D

Deleted member 32554

Guest
Disclaimer, don't do floors , but layed 1" s/c topper to pretty up a rough barn poured concrete floor only brushing wet cement slurry as you go , why SBR ,
 

malc

TPF Special Forces
Disclaimer, don't do floors , but layed 1" s/c topper to pretty up a rough barn poured concrete floor only brushing wet cement slurry as you go , why SBR ,

a 1" screed was standard practice for years, as was a cement grout. a floor screed is expensive if it fails. this method was found to fail so it has been improved.

you can lay a screed down to about 15mm with a sbr additive, and cureing it with water and a cover of polythene for a week. if it dries to quickly the edges of a thin screed will turn up, like a slice of bread if you laid it out in the sun.
 

The Hobo

Well-Known Member
a 1" screed was standard practice for years, as was a cement grout. a floor screed is expensive if it fails. this method was found to fail so it has been improved.

you can lay a screed down to about 15mm with a sbr additive, and cureing it with water and a cover of polythene for a week. if it dries to quickly the edges of a thin screed will turn up, like a slice of bread if you laid it out in the sun.
does nobody do asphalt floors any more I still remember the lorrys with the stuff boiling away the smell was great
 

malc

TPF Special Forces
does nobody do asphalt floors any more I still remember the lorrys with the stuff boiling away the smell was great

asphalt floors were only thin and they would accept traffic after a couple of hours , but it is all insulation and under floor heating now.
 
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