Bonding Floor Screed to concrete

[parksy]

I am laying a screed on a concrete slab in good condition (laid about a year ago). The slab has been PVA'd to seal and keep dust down. Is this an acceptable surface to screed onto or do I need a primer or bonding agent?
Thanks

 

[noseall]

we usually prime with a cement slurry which is broomed onto the surface of the concrete.

 

[parksy]

Hi Noseall

Can I get the same effect with a thin 50/50 sand/cement slurry - brushed well into the concrete?

Chris

 

[noseall]

yup.

apply the screed whilst the slurry is still wet. this may mean wetting the whole floor with ordinary water then applying the slurry in stages.

 

[parksy]

That's really useful. Thanks for your help again mate!