Legal Question in Construction Law in Illinois

Replace the expired engineer with a new or refurbished engineer.

"Is it legal" is a vague question. I would rephrase it to "What are the consequences of using an expired stamp?"

The primary concern, of course, is whether the drawings show a safe construction. If not, relatively few people care whether the stamp is up to date.

Using an out of date stamp may be a sign that the engineer's license is expired (or that s/he just used the wrong stamp). Check with the licensing authority to make sure the license is actually expired before taking any extreme action.

If the engineer is working without a license, it could affect insurance coverage, permit approvals, constitute a breach of contract, and otherwise interfere with the smooth operation of the project.

Re: Engineer Stamping

The answer that in no case is this legal. In essence an engineers stamp says that the person who stamped the drawings either supervised or performed the engineering work as listed in the drawings.

If the license was revoked this can have serious consequences. A structural certification as an SE has extremely significant consequences.