Hello everyone,

Need some advice/guidance,

I have a new construction in progress. The floor system is comprised of 2x4 web engineered joist and 3/4 inch sub-floor. The joist are set on 22" centers. I am planning on installing 3/4 inch hickory hardwoods. Problem is, for it to look aesthetically pleasing, I would need to run the hardwoods parallel to the joist. So I am getting some varying advise from blocking the joist to adding 1/2" plywood.

My concern with the blocking is three fold. 1 - with the joist being the 2x4 web design the blocking would have to lay flat and I question the strength value that that would bring, 2 - being 22 inch on center joist, the blocks would be longer in this application, again leading me to wonder if there would be much strength value added with the blocking, and 3 - it's ALOT of blocking.

With the plywood, I am sure it will stiffen some, but I still am concerned again with the spacing of the joist that some rolling may occur with the hardwoods.

Anyone haveh suggestions or advise on how best to proceed in a manner that I can keep the hardwoods orientated in the direction that I want? I would appreciate to hear it.

Thanks in advance.

George

I think a full trowel of floor adhesive under the half inch plywood, then fasteners with a 6" edge and 8 inch field schedule will be as strong as you need. Another option is to use inch and an eighth inch T&G plywood.
This would be a good question for a structural engineer.