The fire started in the early hours of this morning in the Lower Hillgate area of the town.
The site is a £2.4m residential and commercial scheme for housing association Guniness Northern Counties where the main contractor is local firm CSC Construction.
The job started in March and was due for completion in September to provide 13 flats and 300 square metres of commercial space.
A Guinness spokesman told the Enquirer the fire was now under control but the surrounding area had been evacuated following fears that a wall on the site was in danger of collapse.
A statement from the housing association said: “We would like to thank the Fire and Rescue service for their prompt and efficient response and although the incident has now been brought under control the ferocity of the fire has completely devastated the new homes and offices that were due for completion this September.
“Along with our partners at Stockport Council and CSC Construction, we are deeply dismayed at the news of this fire but grateful that no one was injured.
“We remain committed to the regeneration of this area of the town and will be meeting with Stockport Council as soon as we have fully assessed the situation to agree the way forward.”