The main task of the Stained Glass Workshop is to restore stained glass windows of Nidaros Cathedral, which were primarily created by Gabriel Kielland between 1908 and 1935.

Stained glass windows of Nidaros Cathedral are continuously restored and maintained. Most of the stained glass windows of the cathedral were drawn by Gabriel Kielland and created by him and his assistants between 1908 and 1934. Various issues with the windows involve frequent restoration. This is due to material fatigue and weakening of the lead profiles, insufficiently fired paint causing paint peeling, ice formations and, unfortunately, rare occasions of vandalism.

Craftspeople at the stained glass workshop perform all aspects of stained glass window restoration. This includes everything from removing stained glass from the window openings to creating new lead profiles, repairing broken glass, painting new glass pieces and re-applying lead when necessary, as well as re-installing stained glass pieces in their original positions. The workshop continues to develop by testing new methods and updating their restoration ethics, while also working with traditional stained glass craftsmanship methods.

The workshop also accepts consultation and restoration assignments for other churches, institutions and private clients. There are a limited number of craftspeople who restore stained glass windows and lead glass in Norway, with even fewer workshops that accept tasks involving painting new glass pieces for the restoration of a stained glass window. NCRW's restoration glass workshop also prepares status reports with recommendations for remedial work.