"It's a terrific location for a first-class office building,"says a broker familiar with the property on Jones Road. The sourcealso maintains that the development will be well-received bycompanies scrambling to find adequate quarters. "The marketplaceneeds the space," says the source. "In all areas, we are badlyundersupplied."

Nowhere is that more true than in Waltham, considered the mostdesirable office destination in the suburbs. With a 4.7% vacancyrate, according to Meredith & Grew, the 20-million-sf Route128/Mass Pike submarket has barely 900,000 sf available, andvirtually nothing contiguous over 50,000 sf. After beginning theyear with rental rates in the mid-$30 per sf range, Waltham is nowcommanding rents above $50 per sf.

Boston Properties Senior Vice President Claude Hoopes says thatbecause several projects under construction have already leased up,the effective vacancy rate for Waltham is between 2% to 3%. Whenthe Waltham Weston Corporate Center is completed in 15 months,Hoopes believes the six-story building will be well on its way tobeing fully committed."It's going to be one of the only games intown in that submarket over the next 24 months," he says. "It'sjust an incredibly tight market."Hoopes says Boston Properties hasthe capacity to construct another building at the development,adding that the firm had mulled increasing the initial phase tobetween 375,000 sf and 425,000 sf before opting to focus on onestructure for the time being. ADD Inc. of Cambridge is thearchitect.