We are wanting to put in Oak flooring, but I have been told I will have issues. Our home is 5 years old and the builder used 2x4 truss joists. The floor does have some bounce in it in various areas, but my neighbors have Oak fllors that the builder installed with no issues.
your topic says 24" and your post says 2x4,i assume its 24" on center,but not with 2x4's. it depends how thick the plywood is across those joists.thicker is better, also the direction of the hardwood(accross the joists,not along them)look for an air return vent and see how thick your plywood is,also check your neighbors.but to be safe add a layer of plywood 1/2 to 3/4 to the existing floor...good luck
The floor joists are made with 2x4s, but are contructed like a roof truss with cross members, etc. My neighbor has the same and they are 24" oc. There is 3/4 in OSB underneath. Sounds kinda strange I know, this one builder here in the Denver Metro area uses this kind of floor joist/truss. One floor installer said it is no problem, while others frown. One floor guy is quoting $4/ft for #2 HW, it looks nice, but I think we will go with #1.
3/4" osb is the very minimum subfloor for a naildown hardwood,here's what i would do.ask each bidder if they will guarantee the job with the subfloor as is..once you have selected a floor ,call the mgf.to ask what they will guarantee/and what they recomend.. fyi...at one time(just a few years ago) no mgf would guarantee a floor installed over osb...plywood only.....good luck