Work is due to start on Newhaven Library on Monday June 2.
East Sussex County Council said contractors would be on site next week.
At this stage there is no official opening date for the library.
The first stage will be preparation of the roof and the ground floor for the library.
The £1.6m facility was meant to be ready at the end of 2013. Newhaven Library in the High Street will hold a wider range of community events and activities.
It will occupy the building which formerly housed clothing retailer M&Co.
A community hub will be based in the facility too.