Old Government Buildings box-frame and sash window restoration project

31/08/2020
A recent workshop provided an opportunity for heritage supporters to help with a restoration project at the Old Government Buildings in Wellington and to learn some of the traditional skills needed to repair and restore the sash windows.

One of the participants was David Kiddey, a former New Zealand Historic Places Trust (NZHPT) Board member, and a past chair of the Wellington Branch of NZHPT. David now lives in Dunedin. 

Mike Deavin, a semi-retired qualified ecclesiastical joiner, who manages the OGB restoration project, led the workshop and provided the hands on training and supervision. The key objective was to learn how to change the sash cords and incorporate the new sash cord to the existing cast iron weight, most of which weigh around 22lb (10kg) each. The new sash cords are a strong synthetic nylon. The original cords were made from hemp fibres, but none of these are known to be in use at OGB or other historic buildings.

The most difficult part of the work was removing the outer beading (known as staff bead) and the inner beading (known as parting bead). Once these were carefully removed the box-frame pockets concealing the weights could be accessed. After changing the cords and replacing sash and the beads, a coat of candle wax was applied to the inside edge of the frame to assist the up and down motion of the sash window.

The project involves work on over 800 sashes. A family joinery business in Lower Hutt still has the skills to replicate the original sash using the original totara hardwood as the replacement joinery.

The workshop was deemed a success and Mike and the team will be arranging further workshops.