I had an 4 foot section of rim Joist installed to replaced rotten ones. This house has two sandwiched together. the new ones seem to be 1/8" taller than the old one. Is this common. Is it that the new ones now days are cut different or from manufacture. I would have never thought to measure. I assumed a 2x10 was a 2x10. Should they have ripped it or will it shrink over time when it dries more. This creates a problem. Now 12 " x 3' section of sub floor that was replaced is up 1/8 " above existing floor. should I cut sub floor now to lay just on the joist? is this a common method because this is how someone installed it last time when it rotted 20 years ago. Thanks.

 

Dimensional lumber will commonly vary 1/4". Especially when you get over 2x8's. If its too big rip it down or trim it with a hand (power) planer.

 

Did you buy kiln dried wood or is it pressure treated?

 

Dimensional lumber has never been dimensional since the 1900's, here is more information that you probably wanted to know!

Harvard Design Magazine: Nominal Versus Actual: A History of the 2x4

 

It is not pressure treated.

 

Since it's not PT the wood should be dry and not expected to shrink. I'd shave/rip 1/8" off of that joist.