The aluminium door and window specialist had outgrown its Birch St premises, in Harbour Basin, where it had been for about a decade, having gone from several staff to about 30, managing director Mark Baker said.
It took several years to find the right spot before a site in Odlins Pl in Mosgiel, at the end of the Taieri Airfield, was settled on and Calder Stewart was under way with the build.
On Saturday, staff would visit the site for a barbecue and to get the feel of what was being built, Mr Baker said.
The 1500sq m factory was just about double the existing premises, while there would be an additional 350sq m of office space and a show room.
It was scheduled for completion at the end of the year.
The firm’s core market consists of residential — new homes, alterations and replacement joinery — along with some light commercial.
