Manufacturer and distributor of doors and doorsets . Premdor UK operates as part of the Masonite global organisation and upholds the high standards and values set by Masonite. Premdor is a leading UK joinery manufacturer operating from its Barnsley, South Yorkshire head office with other sites in the UK. It is a division of Masonite, one of the world's largest joinery manufacturers. With one of the widest ranges of doors available in the UK, Premdor is renowned for its commitment to quality manufacturing and excellent customer service.