Sub floor preparation is the key first step for a successful hardwood floor installation. There were some raised seams that needed sanded down so we don't have peaks in the newly installed floors. We then used the buffer to clean up the dirt, paint spray and other junk from the floor. Then we sealed it using #BonaR540 sealer to protect the floor from humidity swings in the basement. Only then were we ready to install the 8 inch wide engineered white oak flooring. When flooring is 4 inches and wider, we glue and nail the floor down using Bona's 850T wood flooring adhesive, regardless if it is engineered or solid hardwood. That way the boards are fully fastened to the subfloor and we've minimized the risk of them becoming squeaky over time. We'll be back in a little while to sand and finish this floor.