Hardie Board, WonderBoard and Durock are all classified as cement boards. These sheet goods are made with a mixture of Portland cement and sand instead of the powdery gypsum that’s used in drywall.

The advent of cement backer board has made it possible for do-it-yourselfers to lay tile like a pro. The reason: For most installations, it eliminates the need to set tile in a thick bed of mortar.

The sand deserts in the oil-rich Gulf countries present a practical paradox: though surrounded by almost boundless swathes of desert sand, much of it is not suitable for farming due to lack of water.