Engineered wooden floor on rough screeded concrete

[vargen]

Hi all

I've taken up old, worn out chipboard and 20mm polystyrene sheets to expose a very rough, shallow and uneven screed over pre-cast concrete planks in an upper floor ex-council flat. The screed must have been an unsupervised Friday afternoon operation and I'm undecided whether to use leveller before laying the floor or to risk it.

The plan is to re-lay the polystyrene sheets for thermal insulation with Duralay Silentfloor Gold underlay for impact sound reduction (transmission in the flats is diabolical) under the floated engineered timber.

I assume I should lay the polystyrene on the screed with the underlay above it, but maybe it should be vice versa.....?

Any advice on this vexing question will be greatly appreciated.

 

[ree]

SLC will bring the screed surface into a reasonable flat plane.

Mfr's Inst's must be followed with the floated engineered flooring - read the packaging and call the Mfr's tech dept.

Others on here will have more knowledge than me about the underlay business for this finished floor.