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Sunday, February 20, 2011

Specifications of a metal roof

Specifications of metal roofing
- Light Weight

- Portability

- Durability. The lowest end metal roofing (thin gauge with acrylic or polyester paints) commonly called AG (agricultural) or Utility panels will last 20–30 years which is roughly 2 times the lifespan of an average asphalt roof. Most metal roofing products today come with warranties from 25 to 50 years. Sheet materials like stainless steel, copper, zinc and aluminum are inherently durable; the oxidization of the base material forms a protective patina. Some modern steel roof sheeting materials are coated with an alloy of zinc and aluminum to give it some of the durability of each of those materials at a lower cost and higher strength than either. Copper and Zinc details have historically been proved to last upwards of 100 years with little or no maintenance. The average life-span of asphalt shingles today (since 2001) is 6–9 years [citation needed], while residential and commercial grade metal roofing usually lasts from 50-100+ years, depending on the type. The coatings and fixings on steel roof sheeting can be designed for different environments including industrial and marine locations.

Metal Roofing
- Metal roofs are often used to cover large buildings because of their high strength to weight ratio. The roof of the new Wembley Stadium is an example. It consists of approximately 40,000 sq ft (3,700 m2) steel sheeting.

- Fire and spark resistant.

- Hail resistant.

- Wind resistant.

- Snow shedding: Painted metal roofs are usually snow-shedding. Snow can usually collect when it is fresh and lighter weight. As soon as the ambient temperature rises a couple degrees, the snow usually just slides off. For this reason metal roofing is ideal for homes in northern or mountain regions.

- Metal is readily recyclable. Aluminum and copper roofing products are available with over 95% recycled content. Most metals can be recycled over and over without losing any valuable properties. Recycling is very efficient. As an example: recycled Aluminum only requires 5% of the energy to produce as does new Aluminum.

- Design flexibility: Some Steel roofing products can be installed over open framing, or on a solid substrate.
- Large sprung curves.
- Rolled bull-nose shapes.

- Energy efficiency. Coatings with high reflectivity like Kynar with "cool roof" pigments commonly save 20-30% on air-conditioning costs due to reflecting away much of the sun's heat. Increases the thermal efficiency of buildings in high temperature areas with its cool-roof paints and high emissivity.

- Labor efficient

- Most metal roofing products require very little or no maintenance.

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