The wise city builds its garage upon a rock.
But sometimes that costs more.
On top of the $7.2 million Lawrence is spending on a downtown parking garage, add another $150,000 to make sure the structure doesn't fall down.
The money is needed to make sure the piers that hold the garage up are sitting on solid rock instead of shifting soil. Engineers expected to use a limestone layer beneath the 900 block of New Hampshire as a base, but that turned out to be unreliable.
"What they thought was going to be solid, wasn't," Assistant City Manager Dave Corliss said. "So they're going to have to drill a little bit deeper."
Construction on the new 514-space parking garage, part of the Downtown 2000 redevelopment, began in late October. The project resulted in the removal of nearly 200 private and public downtown parking spaces just in time for the Christmas shopping season.
Dale Glenn, president of GLPM Architects, said in a memorandum that engineers discovered in early December that the limestone layer is "badly weathered, and varied in thickness enough to cause concern."
Construction officials estimate the cost of drilling deeper to be about $122,000. City commissioners Tuesday are expected to approve a $150,000 expansion in bond authority to cover the expenses, with some breathing room added.
Brutally cold weather has slowed the project some, Corliss said, and the need for more digging could extend the time of construction. Completion is expected by October.
"It's better to have a subsurface change order now than when it's built," Corliss said. "No owner likes change orders ... but they are not unexpected."