Concrete floor preparation for vinyl/laminate

Hello, I would say it’s most likely that the concrete floor would still have another layer to be laid on top, in the form of a sharp sand and cement screed. These are normally laid after the roof has been put on. In my experience this job has been carried out by a plastering contractor, with level markings put around the walls of the room so that the floor can be laid level. These floors should be left for at least four weeks to dry out fully and should be a good level base for carpet or laminate flooring. If you were to lay laminate floor straight onto a screed floor, all you would need to do is lay a suitable underlay onto the screed floor, then the laminate flooring would be laid on top. If you were laying vinyl tiles onto a screed floor you would need to prime the floor with a liquid primer then apply a layer of latex levelling compound to take out any minor imperfections, providing a very flat surface for the vinyl tiles to be glued on to. If you have uneven floors such as concrete/screed, latex levelling compounds are used to take out any imperfections providing a flat surface for floor coverings. I hope this helps.

the concrete MUST have the laitence ground off, then a Rh% test must be completed before anyone gives you any advice the Rh has to be below 75% for vinyl or laminate and I highly doubt you are close to that, natural drying is roughly 1mm per day up to 50mm and double the time for a thicker screed. Your flooring professional should do the moisture testing (the builders should have ground the screed but I doubt it so expect to pay for that service) a test involves drilling a hole in the concrete and inserting a sleeve to collect residual humidity levels and takes a minimum of 72 hours to complete, again expect to have a small charge for their time and material usage. For vinyl you will always require some prep work because the screed must be incredibly flat any imperfections will shadow through, laminate has a tolerance of 2mm over a 1m length so will probably require at minimum a floorlayers screed, builders screeds are 90% of the time too rough for installation without professional levelling.