Does a new wood floor really need to be sealed these days? If I missed the sealer coat and have a customer who is counting what is the adverse affects of 4 coats of poly?
Thank you

Oil based poly-urethane will seal the wood on the first coat. Water based poly-urethane will seal the wood, but sometimes it will glue the strips together,where a sealer will allow the boards to separate without having the white line syndrome that can come from the finish bridging between strips.