CHRISTCHURCH

Dorothy explains the method of adding colour to this piece of heritage-style pressed ‘sparkle glass’.

A window into the world of heritage glass

WORDS: Rosemary Baird IMAGES: Heritage New Zealand Pouhere Taonga

When you walk past a heritage building your eyes are likely drawn to the architectural features such as pillars, balustrades, window frames and rooflines. Not so for heritage glass expert Dorothy Ratcliff.

When she walks by a heritage building the first thing she notices is the glass inside the windows. Is it pressed, flashed, drawn, or rolled? Is it flat, or are there ripples and bubbles inside the glass? Recently, several Heritage New Zealand Pouhere Taonga staff were introduced to the world of heritage glass by Director of The Glass Room, Richard Wiki, and his colleague, heritage glass expert, Dorothy Ratcliff.

The Glass Room won the ‘Commercial under $100k’ category of the 2022 New Zealand Window and Glass Awards for Dorothy’s work in restoring the windows and clock face of Christchurch’s Cathedral Square Post Office building. The company is a noted supplier of coloured and patterned glass for use in New Zealand’s older home and public buildings. Dorothy has worked in heritage glass for 30 years, including time at the London Museum and Victoria and Albert Museum. A lot of her work involves reforming or producing glass to match older heritage glass. “The older ‘drawn glass’ was made in a roller and is slightly distorted with air bubbles, or waves that give the glass surfaces a rippling effect,” Dorothy explains. “People might not notice it at first but if I walk past an old building and there is modern glass next to original glass it stands out to me. The whole building looks wrong.” The Glass Room uses all kinds of techniques to match heritage glass. They import heritage glass (newly produced but made in the old-fashioned way). They can then colour this glass by sandwiching layers of colour in between the heritage glass, thus producing modern safety glass which is permanently laminated together. They have their own rollers and kilns,

A small sample of the library of etched glass screens.

where they can refire and soften glass to get an aged look. And they have special techniques to retrofit double glazed heritage glass and triple glazed stained glass. Another prize-winning project was reproducing some of the glass windows at Beath’s Building, which were shattered in the Canterbury Earthquakes of 2010–12. The original windows were drawn glass, but this glass production technique has now been abandoned. After months of testing, Dorothy produced ‘post-circa 1940 heat treated clear window glass’ that replicated the inaccuracies of the old glass but conformed to modern glazing standards.

The Glass Room also does repairs and matches for tram windows, curved cabinet glass, villa doors and more. “We are the only company in New Zealand and Australia that has this level of commitment to producing these types of heritage glass,” says Richard. Dorothy and Richard’s passion for the history and craft of heritage glass is evident. Richard has for years been buying old glass screen prints from companies who have abandoned these old techniques. These are used to reproduce frosted designs on glass, where acid is applied to a screen over glass, and eats away at the glass leaving a permanent frosted pattern. “I’ve bought them from around the country as old glass companies sell up,” says Richard. “It’s a bit like a library of designs. We do etched glass for people all over New Zealand, to match existing patterns. If we don’t have a pattern in stock, we can also print directly on glass which gives a similar result.” Dorothy has been salvaging heritage glass for 30 years. “I’ve saved and stored a lot of glass over the years. We’ve reused quite a lot of it since the earthquakes, and I like to keep a big stock of it so we can put the genuine thing back in. I don’t throw anything out because it’s somebody’s artwork,” she says. For Heritage New Zealand Pouhere Taonga staff it is important to know and understand how various heritage construction professionals work. Fiona Wykes, Area Manager for Canterbury/ West Coast says, “while we cannot recommend individual tradespeople, we do have a list of approved suppliers. More importantly, knowing what is possible helps us give advice on restoration to heritage owners.” Richard agrees that education is essential. “Often people find us too late. They go to a general glazier, who will not have the opportunity to access these types of heritage glass. We are keen to educate the community who support the retention of New Zealand’s historical buildings, so that they understand there are modern solutions to retrofitting and matching heritage glass.” n

Some of the salvaged heritage glass.