Officials at a New Hampshire middle school have chosen concrete over pressure-treated timber piles to support a 1930 section of the school. Chad Weathers, project manager for Gilbane Building Co., said the timber option would cost $76,000, while shoring the piers with concrete would be $100,000. He said the difference in cost is negligible because the concrete option would allow the team to move forward with its schedule immediately, among other factors.