SubFloor Repair?

[DIY_Guy79]

I'm replacing the tile in my kitchen. Found an area of the sub floor near the sink that is rotted & weak due to a leak at some point. It needs to be replaced. Its roughly a 2ft by 6ft area that needs replaced. The area runs directly in front of the counter, but perpendicular to how the original sub floor is laid.

My question is, is there any potential issues with only replacing the rotted area as the rest of the floor is fine? Or is it for whatever reason, more advisable to replace the entire piece and lay it in the same direction it came out?

If I replace the entire pieces, I'll need to basically replace the entire kitchen floor as the area runs perpendicular across multiple pieces. If I just replace the area, its much simpler and of course, cost effective.

Also, how much gap should be left between joints for expansion? And should caulking or anything be used to seal joints or just leave unsealed?

 

[quickfarms]

Are you removing the entire floor down to the joists?

 

[The Cobbler]

replace only the section that is bad. if using plywood, the grain should be perpendicular to the joists for strength. OSB the same thing. screw some blocking in if needed to tie the old & new together . try to run the edge seams parallel to the the joists , on the joist (cut the original subfloor back to half on the joist) no need to worry about leaving a gap, just don't wedge it in there, a loose snug is fine. no need to seal the joints

 

[dogdog]

Not sure how big is the entire kitchen...

I used T&G for it when I rip the 800-ish sqft out... you'll have to cut the pieces so that that joints that is not T&G meets at a stud/joist. The T&G part goes perpendicular ... not sure about OSB...