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Zinc roof

ROOF CORROSION AND HOW TO AVOID IT

ALU – ZINC STEEL MAKES GERARD ROOF TILES LAST LONGER COMPARED TO GALVANIZED STEEL

Genuine Gerard® stone coated roofing tiles are only made using the highest grade Alu-Zinc steel. This ensures a longer life, particularly in coastal locations.
Normal steel will begin to corrode and rust as soon as it is exposed to the atmosphere. An untreated steel roof could only last for one year, depending of course on the weather conditions and proximity to the coast. For a storage or agricultural shed, this might be ok, but for a quality house, it’s obviously not a realistic option.

Galvanised steel is steel with zinc added to it. The zinc is sacrificial and is designed to corrode and rust while the steel remains in good condition. This gives the steel an extra lifespan over untreated steel, so a galvanised steel roof might last 3 or more years before replacement is required. This may be acceptable for some homes and in the long run roofing sheets are usually made with galvanised steel.

Alu-zinc steel is like galvanised steel with aluminium also added to it. It’s a bit more complicated than that as the exact measurements of aluminium and zinc that are added to the steel have a huge effect on its lifespan, but more about that later.

Like zinc, the aluminium is designed to be sacrificial. In basic terms, the aluminium protects the zinc, and the zinc protects the steel. This avoids the white corrosion that occurs with galvanised steel and increases the lifespan of the roof.

At Gerard®, we use an exact mixture of al-zinc that is scientifically calculated to protect the steel in normal atmospheric conditions for 50 years. This is a scientific, mathematical fact. As a customer, it’s important to know your facts, because a manufacturer that uses 1/3rd less alu-zinc will reduce the lifespan of their steel by half. And reducing the alu-zinc content by half will reduce the lifespan of the steel by 2/3rds. Unfortunately, the alu-zinc is invisible to you, so you can’t tell by looking at the tile how much alu-zinc it contains.
This is why you need to source your genuine stone coated Gerard roof from a trusted and reputable partner at Wichtech.