Is there any major problem with running my floor boards parallel with the floor trusses? I'd really prefer that they run that way but if I'm going to run into problems I won't.

Thanks,
Shay

Need a lot more info, : type of "trusses", distance between them, type of sub-floor, any underlayment, type of floor being installed.

Hmm.. standard floor trusses, not sure what the differences are with trusses, 24" O.C. Subfloor is OSB. Flooring is 4 3/4" Teak and underlayment is felt/tar paper.

This project is definitely not a candidate for parallel installation.
I wouldnt do it with more than 12 inch on centre, and a plywood subfloor.

So, out of curiosity, what could happen if you do parallel?

I can pretty much assure you that even now, there are low spots between those trusses in the subfloor. Ideally, if you need to install parallel to the trusses ,you'll need to fill in the low places in the existing subfloor ( I do not recommend patching compounds ) with 3 tab roofing shingles. Than when everything is flat and even, install 1/2 plywood over it, either screwing or stapling very well. Double check for flatness again. Failure to do these steps will most likely result in a floor that is uneven, prone to separating between boards, excessive flexing and noisy.

In addition to the irregularity that you most likely have in the flatness, as Gary says; there is also another longer term concern that I have. The OSB is very flexible on a 24 inch joist centre, so as you are walking on your new floor there will be a lot of flexing of the finished floor between the joists if laid parallel, which will ultimately loosen your nails and create a lot of squeaks. Whose idea was it anyway, to invent that OSB? Should be shot and p....on.

I put on an addition 2 years ago and all the 2nd floor floors are plywood in case I wanted to do wood floors. Unfortunately, that's not where the new floor is going.

So, I gave the wife the bad news and we'll go perpendicular to the trusses in the living room and kitchen. Thanks for the advice everyone.

-Shay