Flooring tiles made of porcelain are denser than ceramic tiles. This quality makes them less absorbent and a good option for outdoor use in climates with cold weather. Porcelain tiles with at least a PEI rating of 4 are scratch-resistant and a good option for outdoor use. Porcelain tiles with a PEI rating of 4 are commonly used in commercial applications, while those with a 5 rating are commonly used in high traffic areas such as shopping malls.