Building Inspection Results.

Inspections of a number of Galvalume sheet roofs, which have been performing in a wide range of environmental conditions, confirm the excellent corrosion resistance of the product and its suitability for these applications. Typical examples of long-term durability are shown in the accompanying photographs. Though weathered by the 15 to 16 years of outdoor exposure, no rust is evident on the roof panel surfaces, cut edges or formed areas or at overlapping joints.

Ideal for Standing Seam Roof Applications.

The demonstrated outdoor performance of Galvalume sheet makes it the ideal choice for standing seam roof applications. Compared to a single-ply or built-up roof the advantages are very real--both in performance and cost savings over the life of the roof.

For example, the Galvalume sheet roofing (about 1.5 lb/sq ft) is lighter than either a built-up or single-ply system (up to 15 lb/sq ft). The lighter deadload can result in reduced support structure weight and foundation costs.

A Galvalume sheet standing seam roof system requires very little slope for good drainage (1/4 in. in 12 in. minimal)--it�s perfectly suited to low-roof profiles. And it can be installed year round, so there are no construction delays. That means earlier occupancy for the owners.

Also, a Galvalume standing seam roof isn�t plagued by the thermal shock, ponding water and inevitable leakage that occur with built-up roofing.

And equally important are its low life cycle costs. A recent computer study conducted by the Roofing Communications Network found that the standing seam roof enjoyed the longest life expectancy and the lowest life cycle costs of any of the built-up and single-ply roof systems with which it was compared.

Good Resistance to Standing Water

As in all well-designed roofs, standing water (ponding) on Galvalume sheet surfaces should be avoided by providing free drainage from the roofing panels. In multi-slope roofs, where ponding may be impossible to avoid, a valley gutter or other drainage device should be used. If ponding does occur (a critical consideration for low-slope roofs), cyclic immersion tests confirm that Galvalume sheet endures several times longer than either galvanized G90 or aluminum-coated, type 2 sheet before the onset of rust. Inspections of roofs up to 15 years old also confirm this fact.

Excellent Energy Efficiency.

Galvalume sheet�s metallic surface provides excellent reflectivity. Additional, a Galvalume sheet standing seam roof enables the use of a generous amount of insulation. Together, these two factors result in a long-life, cost-effective, energy--efficient roofing system.

Excellent Formability.

Galvalume sheet can be formed about as readily as continuously annealed galvanized sheet steel. Lock forming and roll forming are readily accomplished. A lubricant should be applied and chromium-plated rolls used to minimize coating metal pick-up on roll-forming dies. Solvent-based lubricants, which do not leave residues, are suggested.