Updated guide to hardwood floor installation: choose between solid and engineered boards, prepare a stable subfloor, control moisture, plan layout, leave expansion gaps, and use the right underlayment and fastening method.
Engineered hardwood can be installed over concrete if you control moisture. Test the slab (ASTM F2170/F1869), follow manufacturer's moisture limits and acclimation instructions, and choose the right installation and mitigation methods.
A floating wood floor is an engineered floor that locks together and rests over the subfloor rather than being fully nailed or glued down. Modern options include longstrip panels and engineered planks with click-lock systems; they are more dimensionally stable than solid hardwood and often suitable for basements and over concrete when installed per manufacturer instructions.