USE OF SHINGLES FOR ROOFS

Press, Volume XCI, Issue 27633, 14 April 1955, Page 11

USE OF SHINGLES FOR ROOFS

REPLY TO FIRE BOARD TESTS SEVEN YEARS AGO RECALLED The decision, of the Christchurch Fire Board to oppose the use of shingles for roofing and references by the Chief Fire Officer (Mr L. R. Osmond) to the fire danger created by shingles were challenged yesterday by Mr H. S. Cook, manager of a Christchurch timber company. “It is a pity that the Chief Fire Officer has no later information than the Great Fire of London to refer to,” said Mr Cook. “This occurred in 1666 and history books show that houses were then thatched with straw and reeds, which would of course blow about.

, “Possibly because of import restrictions at that time, Canadian cedar shingles were not then available. Cedar is a fire-resistant timber, the shingles are nailed down and cannot possibly blow about.” Mr Cook asked if Mr Osmond could quote a single case in Christchurch were fire had been caused through a shingle roof or spread from brands blowing about. In 1948 a fire test of western red cedar roofing shingles had been watched by representatives of fire underwriters, architects, the Housing and Public Works Departments and the City Council, Mr Cook said. A model roof section, using shingles 16 inches long to give a triple overlap in every part, was tested with a blowlamp working at full pressure. After the test the City Council approved the use of western red cedar shingles for roofing, but decided that no otjier timber would be permitted. The housing and town-planning committee reported to the council that there was little fire risk. It said that when a shovel full of burning coal was placed on the roof section it hardly marked the top shingle. British Report

Mr Cook produced a report on the performance of red cedar shingles in Britain prepared by Mr I. J. O’Hea, F.C.1.5., in which he said Canadian edge grain western red cedar shingles could be accepted with complete confidence as a permanent roofing. On the question of fire risk, Mr O’Hea stated that 98 per cent, of fires began inside a house and if the fire reached the loft and the rafters whatever was on the roof would collapse. Cedar shingles tended to stifle and kill instead of kindle a fire and the fact that they were light reduced the damage from roof collapse. “But what about the risk of firebrands of any kind being carried through the air and landing on a cedar shingle roof?” he continued. “I hope to be able to prove convincingly that it is almost physically impossible to set fire to an edge grain red cedar shingle roof from the outside by any possible firebrand which might land on it.”

Western red cedar was a slowburning wood, he continued. If a single shingle was placed on a fire it would burn eventually, but built into a roof it was a different matter. The roof became in effect one solid homogeneous piece of timber and it was almost impossible to ignite it from the outer surface. He then described a test with a blow-lamp similar to that conducted in Christchurch.