Aluminum
Introduced in the 1940's aluminum siding once enjoyed a fair share of the non-wood siding market. Soon after introduction it was offered in a variety of enameled colors. It was low maintenance, resistant to corrosion or deterioration, lightweight, durable, and needed minimal repainting. Aluminum siding's popularity declined after the introduction of vinyl siding, which is cheaper and unlike aluminum siding is not prone to denting. Today, some aluminum and steel sidings have a PVC color protective coating which improves durability offers greater color selection. These coatings increase the negative environmental impacts of the material by introducing PVCs into the product, and may affect recycling of the siding at the end of its life.