The advice you were given was 100% correct happy you found a proper tradesman to do your job correctly you would be surprised at how many jobs I attend where corners have been cut because of incorrect advice
Bostic do a good dpm sets in 4 hrs
uzin and artex do suitable screeds both water based or latex based both relatively inexpensive
But you will need a trades man to do the screed correctly the dpm is potentially a diy product as long as you mix as per the instructions and quickly apply with a...
Hi I am a floorlayer with 40yrs experience
I would suggest applying a liquid dpm over the existing asphalt and filled area then applying and 3mm screed cost you should then have a floor suitable for any type of flooring and will eliminate any damp