I was retained by the homeowner to come to his home and find out why his floor was making so much noise. The floor was a 3/8-inch engineered plank and mechanically fastened using 1 3/8-inch staples. This was a DIY project, and I have to admit the owner had done some pretty incredible work to his house. His fastener placement was well within standard, his end-joint spacing was greater than standard and there were no H joints. He went on to say he followed all installation guidelines to T. His floor should not have been making any noises.
During the inspection, I interviewed the owner and found out he purchased the flooring at a local box store, including the underlayment material. During his selection process the sales professional told him what nailer and staples to buy, as well as the underlayment material to use. He said during the process the sales professional kept asking him about his kids and the noise they make in the basement, and he suggested a premium sound pad. The sales professional said the upgraded pad will reduce the noise from the basement. During the inspection, the pad was measured at 2.5 mm. It was designed for a floating floor, not a nail-down floor. Of course, what the sales professional failed to disclose is that when a wood floor is mechanically fastened to the substrate, there cannot be any vertical deflection. If there is, the wood floor will make snapping/popping noises. Also, inserting a fastener through the pad will reduce the sound reduction capabilities by 90 percent or more.
When this information was disclosed to the homeowner during inspection, not surprisingly, he was very upset with the box store. I told him it wasn’t the hardwood’s fault from bad milling, or deflection in his subfloor, just a bad choice on underlayment material. He wanted to know what the fix was; he had read online a potential fix was screwing the floor from the basement. When I told him the only solution was to remove and re-install the floor, that made him very angry. He brought up his complaint to the box store, bringing up the point that this premium underlayment was triple in price but was not designed for a nail down application, but he found no resolution for his concern.
This should be a lesson for all installers and homeowners that any vertical displacement will cause noise in wood flooring, and the use of any compressive-type pad with a floor that isn’t designed to have one will create movement and noise.