Donald Insall Associates is an architecture practice founded in 1958 by conservation architect Donald Insall.

The firm specialises in adaptive reuse and conservation projects, including listed buildings and heritage sites such as Caernarfon Castle in Wales, the Tower of London and Trinity College, Cambridge.

It employs a team of 125, including directors, architects, consultants, heritage consultants and business operations staff.

Pictured above is a photograph showing a project recently completed by the studio.

Donald Insall Associates is featured in the Dezeen Jobs Top Companies 2026 list, highlighting studios that set new standards in workplace culture, inclusivity, wellbeing and professional growth. Find out more about the initiative here.