HARVARD — The materials used in construction rarely come up for discussion when the subject is driveways.

The Planning Board this week heard from the engineers representing a local resident who wanted to modify a driveway permit to account for a change in the material used during construction.

The board met with Calvin Goldsmith, of GPR Engineering, for a modification of a driveway site plan for the Kavanagh property on 339 Stow Road. Goldsmith was there because the board’s engineering consultant had sent a letter indicating that the driveway’s base had not been made from materials specified in the permit and thus could not be certified.

Goldsmith told the board that the subcontractor hired to lay the driveway foundation had used a mixture of reclaimed pavement and concrete, and that while that was different than normal, it is an accepted practice by Mass Highway.

Materials of concern to the board included brick and organic materials such, as wood. Such materials could pose a safety concern for emergency vehicle access, by causing the driveway to fail. Goldsmith pointed out that this particular driveway was flat and in an open area, which mitigated those concerns.

Board member Peter Brooks commented that he was not concerned with the material because the board had received adequate documentation that it was acceptable. He did question whether the Planning Board had the authority to make the change or if a variance was required from the Zoning Board of Appeals.

“In our mind, the difference between the material is a de minimus difference,” Goldsmith said. “It serves the same purpose, it is stable and it is not going to compact anymore.” He indicated that going for a variance would be a stretch, because the material meets the Mass Highway guidelines, as required by the bylaw.

The board voted to approve the modification subject to receiving a certified letter from GPR, stating that there is no deleterious material in the driveway base. — Richard Breyer