Riddle of the Lyttelton tunnel tiles

WHAT'S GOING ON?: Lyttelton people have been wondering why the once pristine Lyttelton tunnel tiles, as shown, are now looking poorly.
WHAT'S GOING ON?: Lyttelton people have been wondering why the once pristine Lyttelton tunnel tiles, as shown, are now looking poorly.

Lyttelton folk wonder why their tunnel tiles look so shabby. So do two ex-Temuka brothers.

Drive through the Lyttelton Road Tunnel and you may notice deterioration in the white tiles along the sides.

Lyttelton people have been wondering why the once pristine tiles are looking poorly. Letter writers to The Press have asked what is going on. Avonhead resident Ron Palmer took a look and what he saw concerned him.

Palmer declares a personal interest in the tiles. His father, Len, was foreman of Temuka firm NZ Insulators Ltd that manufactured them. Palmer's brother, Bill, was the company's tool and diemaker who engineered the dies that shaped them.

Len died of a heart attack soon after the tiles contract was completed and six weeks before the tunnel was officially opened. Overseeing the job had been hard on him, Palmer says. The stress might have caused his death. Bill lives in retirement in Timaru.

NZ Insulators was a big company and a mainstay of South Canterbury industry with a staff of about 200. It started the four-year manufacture of the tiles in 1960 with a press it had imported from England for the purpose.

Palmer, a teenager at the time, remembers Temuka as an industrial town. Workmen on bicycles clogged streets leading to the factory just before the 8am starting whistle sounded. At 5pm the whistle sounded again and the men poured out and cycled home. It was a long day and some cycled long distances. Palmer's uncle Wal had returned from serving in World War II and lived alone in Orari, 16km north. He pedalled his old bike both ways every day, often into a nor-wester on the uphill grade all the way home.

The tiles were made of vitrified porcelain, which was judged best for cleanliness, lack of eye-glaring reflection and low maintenance. The process involved baking twice at intense heat and glazing to leave a glass-like finish on the tiles. The result was an almost impervious surface, allowing less than 0.5 per- cent of water absorption. This satisfied the demand for tiles suitable to line a tunnel nearly 2km-long and carrying more than 10,000 vehicles a day.

The standard of manufacture was exacting, Palmer says. Every tile was individually checked in a special metal frame.

A force was applied to the centre of the tile and lights at each corner lit up to indicate if the tile was sufficiently level and even. The required 1.25 million tiles passed the test, were transported to Christchurch and fitted in the tunnel. However, even more tiles were rejected. Palmer says workers labelled the pile of rejected tiles "Mt Egmont".

Exhaustive testing was done in choosing the most suitable adhesive to fasten the tiles to the curved walls of the tunnel.

Palmer says the family telephone would ring at all hours as night staff found problems with the plant. His father would drive back to work and supervise repairs.

Sometimes, as the heat in the oil-fired kiln died down, workers had to crawl inside to realign the "saggers" and restack the trolleys.

The figures (in imperial measurements of the day) indicate the size of the project: 1,250,000 tiles, each 6 inches-square, covered 7-acres of wall along 1.2 miles on each side of the tunnel. The cost, including yellow tiles imported from Britain for the tunnel roof, was [PndStlg]287,000. This was about 10 per-cent of the total cost of the tunnel, not including the motorway that was built to link it with Ferry Road.

Palmer says his father was proud of the Temuka company's success in winning the contract and its performance in completing it. However, it had its challenges and he was "glad to see the project reaching its conclusion".

"He appreciated receiving an invitation to the opening of the tunnel on January 16, 1964, and was keen to attend."

His sudden death at 57 snatched that away from him. He never saw the completed Lyttelton-Christchurch road tunnel, Palmer says.

He adds, with regret, that the imported press and the metal dies Bill engineered were scrapped after completion of the project.

When Bill visited his younger brother at Avonhead over the years, they would take a drive to Lyttelton and admire the gleaming white tiles in the tunnel. When they heard of the damage recently, Bill asked him to take another look.

"The tiles looked pretty grotty," Palmer says. Some cracking was visible and black smears indicated possible water seepage. He thinks this might have been caused by earthquakes. He has heard it said that hydrochloric acid being used for cleaning was the culprit but Bill assures him the tiles are resistant to acid.

The tiles may not look their best for the tunnel's 50th birthday on February 27 but they were a sparkling tribute to a small South Canterbury town's industry when Governor-General Sir Bernard Fergusson performed the official opening.

The Press