I screeded (75mm) a floor about 10 days ago and removed the plastic
sheeting today. There are some areas that are crumbly and once the loose
material is removed a small crater is left behind, say 30-40mm diameter
and about 3 or 4 mm deep. The screed surrounding this appears sound.

Not sure what I did wrong, perhaps it got too dry or not compacted
enough in these areas?

Anyway, I am now looking for advice as to what to do about it. The floor
will be covered with laminate flooring, so in some ways it probably
doesn't matter too much. Could I fill the larger craters with more
screed or as it would be so thin should I be using something else?

Many thanks for any advice,
Jon...