A £24 million regeneration of County Hall in Trowbridge will be within budget and on time, Wiltshire Council bosses have said as the project’s first phase edges closer to completion.

Trowbridge Library, currently based opposite County Hall, will close at the end of August and a new library with 1,000 sq ft of floor space will be unveiled inside County Hall.

It will be boosted by a vast new courtyard at the heart of County Hall which has been covered by a glass roof and will become a café and meeting point for hundreds of council workers and members of the public.

Coun John Thomson, deputy leader of the council, said: “I am pleased to say that it will not only be on time but it will also be under budget.

“This is one of the biggest investments in Trowbridge in recent years and what we want to do is really open up County Hall to the public as much as possible, so people will be able to come in and go to the library, then enjoy a coffee or a spot of lunch.

“It will also be a nicer setting for council workers to come down from the office when meeting the public. It will encourage them to mix in a more social and relaxing atmosphere.”

The space will be available for hire for conferences and wedding receptions – and a register desk will be installed in one corner to make way for the closure of the Trowbridge Register Office.

Phase one of the project will be completed by September, then phase two will run until the same time next year.

Until now public council meetings have had to be held elsewhere in the county because of a lack of disabled access to the council chamber. That problem will be a thing of the past when the work is completed.

Project manager Mark Butt, from Wiltshire Council, said: “We also want this to be one of the greenest public buildings in the country.

“The building will collect rainwater and its design will mean that it will use 40 per cent less energy.

“It is always a fine balance between trying to design a building which incorporates well with the older part of County Hall and being as green as possible.”

An open plan design will feature throughout the entire building while the glass roof, which was installed recently, has been likened to that of the Eden Project in Cornwall. The reconfiguration of the building means there will be around 20,000 sq m of office space.