Editor's note: This version corrects the size of the Town Hall vault.

Lyme - Construction that began in September on the Town Hall and library project remains on schedule and is slated for completion by the fall.

The $5.08 million project calls for doubling the Town Hall's size to 5,000 square feet, installing an upgraded vault, and building a new 6,800-square-foot library with space for archives and community programs.

The project reached its first benchmark with the completion of renovated Town Hall offices in an expanded addition, which town employees moved into two weeks ago, said Janis Witkins, a member of the Lyme Town Campus Center Building Committee. Construction workers are now beginning to transform the main Town Hall building, which once served as a church, from offices to a large meeting hall, she said.

A 400-square-foot vault - four times the size of the town's previous one - is also complete. The metal-and-concrete modular vault has heat-protective insulation that is more suitable for storing paper and electronic media than concrete vaults, she said. Used in other parts of New England, the steel-and-concrete vault will be "the first of its kind" in the state, Witkins said. The town's first selectman and library head had testified to change state regulations to allow towns to use the modular vaults, rather than exclusively mandate concrete vaults.

Construction workers are sheet-rocking the new library building and have installed plumbing and mechanically wired the building.

The town is hoping to open the new library, which will feature the town archives and a community meeting room, at the end of September, Witkins said.

The current library remains open during construction.

The project also received last week its first installment of a $380,000 pledge from the Lyme Public Library Inc., the library's fundraising arm. Town residents originally approved a $4.7 million spending cap for the project, contingent on the town raising at least $1 million from grants and private donations. Residents later voted to raise the spending cap to $5.08 million when rising construction costs pushed the project over budget.

First Selectman Ralph Eno thanked the Lyme Public Library Inc. and said without the donation, the town would have had to whittle down the project with value-engineering options or stall construction until it was able to raise more money.

k.drelich@theday.com