Particle board subfloor - cover with additional plywood/osb for luxury vinyl plank flooring?

Question

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?

Answer 1

particle boards don’t tolerate well humidity so remove them if your place can get humid. They will fail and whatever you put of top of them won’t be properly supported.

For subfloor, both plywood and OSB will work fine. Many use OSB because it is much cheaper and the appearance is not a factor.

If you plan on stacking boards, always overlap the seams for more stability. Align the seam near the center of the board above.

If you put a board on top of the existing PB, make sure you take in consideration that you floor is now raised. For example, you might have to trim around door casing.

1/4 board is okay if there is another board under it. Certain not good enough if they are directly on top of the frame. They will flex.