July 30th, 2013
A solid hardwood floor can be successfully installed in most situations, whether over existing floorboards or over solid floors such as concrete or mastic asphalt. Where there are more extreme conditions, such as in conservatories / sun rooms, unheated rooms, bathrooms, or in areas with underfloor heating, a wood floor can be installed, but there will be special considerations, which I would discuss with the customer.
Installation of the new floor directly over joists is not recommended, as the standard spacing of joists in houses is too large for a satisfactory result. It is much better to install the floor onto existing floorboards, or to install a base of 18 mm exterior ply.
Where the sub-floor is concrete or mastic asphalt, a base of 18 mm ply can be fixed down, onto which the new floor can be secret nailed, or special adhesives can be used to fix the new floor in place.
Concrete floors in new-build houses will take many months to dry out completely (a rule of thumb is one month for each inch thickness of the slab), but to save delays the concrete can be sealed with a surface damp proof barrier, to enable installation to proceed.