LEAD PAINTS NOT SUITABLE FOR ALUMINIUM ROOFS

Bay of Plenty Beacon, Volume 13, Issue 35, 20 December 1948, Page 5

LEAD PAINTS NOT SUITABLE FOR ALUMINIUM ROOFS

. Aluminium roofing was being used in New Zealand to the extent of the available supply, said an ■official of the Housing Construction Department. . Since the war aluminium has Tbeen used , fairly extensively in 'Great Britain. Painting new alumiinium is not as easy > as painting galvanised iron. It is first necessary -to remove the greasy substance -which the manufacturers apply to -the surface for protection during •delivery. A “pickling” solution washed over * the surface is recommended to remove the glaze, but exposure to -the air over a period of six months ■or more may produce the same result. It is important that the laps ;are painted before the sheets are fixed whether the roof is to be -painted or not. Lead paints have been found unsuitable, owing to •their action on the metal, so zinc chromate paints are now generally used. As lead-headed nails are unsatisfactory in direct contact with the aluminium, bitumen fabric washers have been used. Aluminium nails •are used in England, but owing to -their short supply and the hardness of most native timbers they may not be extensively employed in this •country. Great care is necessary in the ■choice of flashings. Lead, now in -common use, is unsatisfactory, and aluminium has been found best for •this purpose. Mortar splashings from bricklayers’ chimney building operations must be carefully removed, as the corrosive effect would be ruinous to the roof. Aluminium roofing has been found to be dearer than corrugated asbestos, but owing to the lack of asbestos and other materials it is anticipated that wider use will be made of the metal in the future.