The practice got the green light for the scheme, a 'gateway' to Ashwell Group's huge 'cb1' development, at the beginning of last week.
According to 5th Studio - which was featured in the AJ's 40 under 40 exhibition earlier this year - the project reworks a 19th-century industrial building with the addition of an entrance hall and tower.
The tower acts partly as a solar chimney and the building is naturally ventilated.
Ashwell's development centres around the city's Grade II-listed station. The developer plans to enhance the station's surrounding area with a new public square to 'improve pedestrian flow'.
It is expected that the new building - which will act as a marketing suite and sales office for Ashwell - will be in use by the end of 2006.