Q: I am working on laying new 3/8″ engineered wood flooring over a wood subfloor. I also have ceramic tile floors which will meet with the new wood floor and which are just under 3/4″ higher than the existing subfloor. I am planning on adding another 1/4″ (or maybe 3/8″ if necessary) layer of plywood subfloor in order to help bring the wood level with the tile. At this point I have two questions: First, someone told me that when laying an additional layer of plywood subfloor that (at least in the case of vinyl) you should glue it rather than nail it since the nails can work up and out. Is that true for engineered wood floor also? Second, which kind of underlayment is best with a 3/8″ engineered wood floor, the foam or the cork? My concern here is that while the foam may initially bring the wood up to the level of the tile it might eventually compress, while the 3mm cork would be less likely to compress to the point of being noticeable. The specific installation instructions do not make a recommendation.
Thanks for you help.
Sandra Romero
A: Nails can loosen over time. When nails loosen in your subfloor, more movement occurs and this is what causes most of the noise in a floor you might hear in a home. Usually to remedy this problem you would use a flooring screw to screw the plywood into the floor joists. This being said I would use screws rather than nails to add additional plywood to your subfloor. You could use an adhesive, but screws will be an easier and cheaper solution which should provide the exact same result.
In regards to underlayment I personally prefer cork because of its many natural benefits, density being one of the major factors. Foam underlayments, even the premium ones, have a bit more spring to them and thus will give your floor a bit more movement than something as dense as cork. In the end if you want the best feel under foot and will hold up the best over time would be cork.
