The projected cost of expanding the overcrowded Salt Lake County jail has ballooned to $550,000 - nearly four times the original $150,000 estimate - and frustrated county commissioners want to know why.

Although a $400,000 federal jail grant is making up the difference, sparing the county any cost overrun, commissioners want to know why the federal dollars did not replace the county's $150,000 jail expansion budget."What we're wondering is, did the project simply expand to take up the funding that was available?" Commissioner M. Tom Shimizu asked a team of sheriff's officers led by Lt. Dan Ipson.

Although the county plans to build a new minimum security jail in South Salt Lake by late next year, the expansion is needed as a stopgap to relieve serious overcrowding at the downtown jail, commissioners decided.

The 20-year-old jail was originally built to hold 350 inmates and has been expanded over the years to an official capacity of 550. But in March it held an average of 677 prisoners daily, with a one-day peak of 707.

The county has leased space at the jail vacated by the Salt Lake City Police Department's move into a new headquarters and plans to expand jail capacity by 20 percent, or 114 inmates.

Commissioners budgeted $150,000 as requested by the sheriff's office for the expansion, described by county architect Tom Triptow as a "paint and redecorate" project. But jail administrators later decided the project was inadequate.

"When we got into it, we decided (redecorating) just didn't provide what we needed to take care of those people," Ipson told commissioners.

The sheriff's office then became aware of available federal money for jails and applied for a grant. The department received $400,000 from the federal marshal's office as part of an agreement to temporarily house federal prisoners in transit to federal facilities.

The additional funding changed the scope of the expansion. It will provide a new heating and cooling system for the expansion, a larger visiting area, upgraded kitchen facilities and increased security measures, Ipson said.

But the growth of costs has frustrated commissioners, who say they gave Sheriff N.D. "Pete" Hayward the money he wanted for jail expansion. They feel the federal grant should have saved the county the $150,000 budgeted for the project.

"The $150,000 figure for this project came from the sheriff's office, not from the commission," commissioner Bart Barker told Ipson. "You sought $400,000 without commission approval, but the county portion was not reduced. I'm glad the project cost coincidentally came to the exact amount of money you had."