subfloor prep
 

i recently had to replace a section of subfloor 4x6'. Problem is i used 3 2x4' sheets of plywood to do this with the 4' laying across the joist. I will be putting down 3/4 hardwood and now im concerned the 3 extra seams i created will cause problems in the future. i didn't have a full sheet of ply and i was kind of in a rush. All seams have 1/8 gap and flex a little. Any input would be appreciated.

The gap is good especially with OSB. As for the flex the perimeter between joist bays should of been flat blocked and nailed or screwed. I prefer screws especially when wood is to be laid.

However I worked for a oldtimer that used his form boards for the subfloor and didn't block. After the hardwood was laid it was a solid floor.