It’s all about the preparation with a new build. .  The moisture content of the substrate (normally Plywood, OSB, 2*1 or concrete) must be below 5%.  This is normally tested with a Moisture Meter.  If the substrate is above 5% there is a likelihood that moisture will cause cupping to the floor boards over time and so must be let to dry naturally or have a damp proof membrane applied.

Wood is a hygroscopic material which means that it is affected by moisture throughout its life.  The solid floor must acclimatise (get use to) to the conditions in your home.  This normally takes about 2 weeks but check with the Wood Supplier and always follow the Manufacturer’s instructions.  Acclimation depends on the region where you live, grade and environment, from rainwater management to the water table level. If the subfloor’s moisture content is higher than the flooring’s moisture content by 4percent or more, cupping may occur. Your building contractor can simply leave the heat on within the house over a period of weeks and this can speed up the drying process (be aware that running the heat will cost money which the contractor is liable for till you take ownership, so it is advisable to confirm how long the heat will be on for each day)

Any contractor worth their salt should carry the full Moisture Sensor Kit so they can measure the moisture in the air (called the Relative Humidity), the moisture in the wood and the moisture in the substrate.  Only by knowing all these factors can you determine if the site is ready to accept your wood flooring. When everything is right you are ready to go.