Aluminum vs. Foam Roofs

Characteristics

• Aluminum roofing is available in long sheets or as shingles that resemble traditional roofing materials. Aluminum is prone to denting if hailstones or other objects strike it, but some manufacturers make dent-resistant aluminum roofing. Foam roofs consist of polyurethane that’s sprayed onto a roof deck and dries as a solid surface. Unlike aluminum, polyurethane foam automatically conforms to a roof's shape. Foam roofs also are less vulnerable to leaks, since they're installed without seams that could allow water to seep through the roof deck.

Energy Efficiency

• Aluminum reflects heat, so it doesn’t draw heat into a home in summer, and it helps retain interior heat in winter. Metal roofing that’s painted white can reflect enough heat to cut a homeowner’s energy costs by 40 percent, according to the Metal Roofing Alliance. Foam roofing, however, may result in energy savings as high as 70 percent for homeowners, according to some manufacturers, although no independent roofing agency attests to this figure. Foam roofs are usually white, so they naturally reflect heat. Manufacturers indicate that foam roofs also are airtight, so they retain more interior heat in winter than aluminum roofs do.

Roof Weight

• The light weight of foam and aluminum makes both products suitable options for covering old roofing materials, since they add less weight to a roof deck than other products. In some cases, aluminum roofing is lighter than foam, because some aluminum products weigh just 50 pounds per 100 square feet. Foam roofs generally weigh about 60 pounds per 100 square feet.

Warranties

• Manufacturers’ warranties on metal roofing vary, but aluminum roofs may come with warranties that range from 20 to 50 years. Some companies assert that their foam roofing can last as long as the buildings they cover, because the solid surface of polyurethane foam strengthens a roof. However, the foam needs to be reapplied as often as every five years to maintain it properly.