(12/15) The cost estimate for a joint town and county police building in Thurmont has skyrocketed since town officials proposed the project in August, and the building may turn out to be much larger and more expensive than what the town can afford.

While county staff had originally estimated a cost of $150,000 for the design of the building in August, they told town officials Tuesday that design costs would be closer to $235,000, Mayor Martin Burns said.

Town and county officials agreed to pay $75,000 each in design costs when they met in August.

The increased design cost estimate is based on an increase in the overall size estimate for the building from 11,000 to 15,000 square feet. The exact size for the building has yet to be determined.

In addition, the construction cost estimate for the building has gone up 20 percent since August, based in part on increased materials costs since Hurricane Katrina. This means the town could spend more than $3 million in construction costs alone, a figure that is much higher than what town officials had initially anticipated.

The board was split Tuesday on approving an expenditure of up to $13,000 to sit down with an architect to come up with a more exact size and cost for the building. Commissioners Glenn Muth and Ron Terpko voted against approval and Commissioners Bill Blakeslee and Wayne Hooper voted in favor of it. Burns broke the tie by voting in favor of the expenditure.

‘‘Somehow this has gotten out of hand,” Muth said. ‘‘Now we’ve got a project we don’t need and can’t afford.”

Town officials are considering using the design of another police building, such as the one in Taneytown, and expanding on the blueprint to save on design fees for their own building, rather than partnering with the county.

Burns made it clear that the town would move forward with building a new town police building, with or without the county as a partner, ‘‘for the reason that the public stated emphatically that they wanted a police building,” he said.