We have a hardwood living-dining room floor that was improperly installed (before we arrived), and squeaks and creaks something awful. We plan to rip out the old flooring and put in LVT (luxury vinyl tile) that locks together and looks similar to hardwood. (Example.) We used something like this in our previous house and were very happy with the results.
The subfloor has a bulge in the middle. We think that there is a structural beam there that used to have a dividing wall over it. We suppose the house (built in the 1940's, upstate New York) settled around the edges, leaving the silly bulge in the middle of the floor where there wasn't any sinking.
My first question is, do we need to level the subflooring before laying the new flooring? (I want to make sure we don't end up with a creaky floor again when we're all done.) If so, with what method? I have read about using roof shingles, and I've also heard about putting down little strips of different thicknesses and then putting down a new subflooring on top of that.
Second: the floor here is cold and frankly in some places feels rather drafty. Would an underlayment (such as TrafficMASTER Premium 3-in-1 Underlayment) help? The friend who is going to help us install the flooring says he has always used a single thickness of newspaper instead of a commercial underlayment, and that has worked great for him (!).
Note that we have a semi-finished basement under the main floor of the house. In principle we could put in some insulation batting in the "ceiling" of the basement, instead, if that's a better approach.
Alternatively, should we paint the subflooring with some sort of waterproofing? Not that there's a water or moisture problem, but I wonder if that would be a good approach. And/or caulk around the edges of the subflooring?
Lastly, how smooth does the subflooring need to be? Obviously I don't know what it looks like yet -- but once it's exposed, what should we be checking for, e.g. nails sticking out, rough surfaces, dust and bigger particles, etc.? Should we shop vac the whole thing?
Most of these same questions regarding the prep for the bedrooms, where we are going to put carpet (after pulling out the creaky hardwood flooring). The floors in the bedrooms feel particularly cold and drafty.