A finished floor will only be as good as the subfloor that it is laid on.
The ideal substrate should be smooth, level and even. New subfloors should be prepared in line with British Standards 8201, 8204 and 5385 and technically there should be no more than a 3mm vertical deviation over 2m in any direction.
The subfloor should be checked for moisture too. If moisture is present then wooden floors will expand and warp and stone tiles can pop - so testing is essential. If moisture is present, there are ways to apply a barrier so that the moisture isn't transferred into the flooring.
Heated floors, in particular, create a challenge for flooring and so it is really important that installation is carried out correctly. In particular, installing over heated anhydrite screeds requires careful handling. New screeds need to cure and dry and in general the curing rate of a screed is 1mm per day for the first 40mm and thereafter 0.5mm per day. So a typical 60mm screed will take approximately 80 days to cure. Because of the many different types of screed available, specific advice on the curing and drying times should be sought from your screed and underfloor heating supplier.
At Strathearn, we have years of experience installing our natural stone and timber flooring, especially onto in-screed underfloor heating. We have invested time and money in ensuring that our teams have the most up-to-date knowledge and equipment. We are dogmatic when it comes to ensuring the subfloor conditions are right and ready before we install - we care about your beautiful floors as much as you do and so compromise just won't do.