OSB Subfloor Causes Oak Floor To Pop


Two years ago we had 3/4″ oak floors installed in our new home. The oak floor was installed over OSB rough flooring. This floor is supported by a truss floor, which has some give to it. The problem is that the floor pops when you walk over it. Is there any way to eliminate this popping?



Dear Dwight

It is very likely that the OSB is the problem. This material is just about the worst performing subfloor yet made. Often during construction the OSB will get rained on and swell along some or all of it’s edges. Once the roof is on and the subfloor dries out, it doesn’t settle down entirely. The builders make an attempt to nail down and sand down the edges, and this might be fine until a hardwood floor is mistakenly installed on this rather inferior nailing surface.

Then two things can happen, either the hardwood floor nails or the subfloor nails loosen in this material and start this popping. Or in rarer circumstances the OSB fibbers that have been water damaged start to break and create most likely what you are hearing. The good news is that if the later is the case, the damaged fibers will in some time all break and the floor will quiet down on it’s own. But I’m not sure what the floor nails are gripping into by then, sawdust?

By all means have the builder take a look at the problem, and be sure to keep track of when the problem started. Most new houses in North America are covered by a new home warranty, and this sort of thing may be covered.

There are a couple of solutions. The best is to remove all the hardwood and OSB and replace the OSB with 3/4″ plywood glued (with a urethane adhesive) and nailed (with 3″ spiral nails) to the joists. Do this for the whole house if at all practical. At least do that in the problem areas.

If it is just going to be only a patch job you will of course only be able to use the same plywood thickness as the OSB. In either case you will have to replace all or do a major repair on the hardwood. If it’s prefinished (you didn’t say) make sure it matches the old floor. But if it’s sand on site, make sure that the whole floor is resanded to blend this job in better. You may need to be compensated for having the floor resanded, as this removes about 1/6 the useful life of the floor.

You may try a product called Squeak Enders at http://www.squeakender.com. This may provide a temporary solution to some the worst areas, but you have to have access to the underside of the floor. Let me know if cannot get under the floor, and I will teach you a re-nailing technique from the top, once I know what kind (site sanded or prefinished) wood floor you have.