Self leveling didn't adhere properly

[knightmck]

A while ago I lifted a tiled floor in my hall (concrete floor with a DPM) to lay a engineered wooden floor in its place. Obviously when the tiles were lifted not all the adhesive came with the tiles.
After taking the worst of it off I noticed that there were some high and low spots on the floor so decided to use self levelling compound to sort this out.
The floor was hovered well and a PVA sealer applied. The self levelling compound (just from a local DIY chain) was mixed according to instructions and appeared to work fine.
However after it was dried for a few days I noticed that some sections of it sounded hollow.
Any ideas as to why the self levelling didn't adhere properly?
When I used the PVA it was down for a few days before I used the self levelling...is this OK to do or should the self levelling be used while the PVA is still tacky?
Also the self levelling took a couple of days to dry out...so did the PVA create a barrier between the concrete floor and the self levelling preventing it from taking?

Thanks

 

[crazydaze]

Has the floor been moisture checked? As a basic guide, try taping a plastic bag to the floor for 24 hours and see if a dark shadow appears indicating moisture in the subfloor. If all appears dry and you are sure there is no damp, most screeds can be used with a primer rather than pva that should work with the screed and eliminate any potential issues with a bond failure. Check the F-Ball or Ardex websites for more advice etc.

 

[Richard C]

Why did you use PVA? Which SLC? Did the manufacturer recomend it?

Even so, it's almost ceretainly where youve gone wrong.