I am a residential designer, but do not have much experience with Wood Foundations. My client would like a wood foundation with an I beam for support in the center. The engineer that previously drew up the plans over spec'd using a W10x22 I-beam with add'tl rebar.
Can I keep the same I-beam or should I go smaller? Can a wood foundation handle an I-beam AND have the house moved onto it? Normally 2x6's are used, should I go to 2x8 or 2x10 to handle the load? Anyone out there with info that may help?

How do you know the original beam was over-spec'd?

What do you mean, "have the house moved onto it"?

Don't understand "with add'l rebar"...where would the rebar be?

What do you mean by "to handle the load"?

It appears that you are in 'way over your head here as a designer, and one should not expect structural design from a forum such as this. A W10x22 is a fairly light steel beam, so I suspect the original engineer knew what he was doing.

The house currently has no foundation, therefore the house will be moved onto the new foundation, once it's complete.
I have not brought the engineers drawings for review, but apparently the rebar has been over spec'd by about $5000. They spec'd a W10x22 I-beam. Should I stay with that beam size? How about the beam connection to the wood foundation? The existing drawings show grout, but I do not think that will work in this case.

Still don't understand..where is the rebar in a wood foundation? And WHO says it is over-spec'd? How can we possibly know whether the steel beam is oversize or undersize or just right?

How can you expect us to do structural design with no information, for free? If you are unable to do it, your ethical obligation to your client and the community is to retain the services of someone who can do it.