A friend of mine just purchased a 1 story house and we spent the weekend tearing out the old crappy carpet / vinyl flooring. The subfloor underneath it is particle board rather than plywood/OSB. The subfloor seems to be in good condition and goes over a crawl space, with the only issue being furniture, etc "shaking" a bit when walking around. The home inspector said putting an additional layer of sub-flooring over top should help solidify everything. We plan on installing luxury vinyl plank flooring.
-Is it worth putting an additional sub-floor on top?
-What would be better for this application - plywood or osb?
-Would 1/4" be sufficient or what would the recommended thickness be?
-Should we follow the same seam pattern on the existing particle board subfloor or overlap the seams?