backerboard

Noun

backerboard (countable and uncountable, plural backerboards)

1. Boards used as underlayment for tile, plaster, or other materials.
   • A tile setter mounts colorful American-Olean ceramic tile on a new gypsum backerboard in a motel bathroom...1962, “A building product for any need”, in National Gypsum Company Annual Report, page 4
   • Ceramic tile has a well-deserved reputation as a durable material, but neither tile, nor cement backerboard, nor latex thinset or grout, can be relied upon to provide waterproofing protection.2000 November 21, Michael Byrne, “Liability and Waterproofing in Ceramic Installations”, in Floor Covering Installer
2. A sacrificial board placed behind or under a board being drilled or sawn, so as to prevent blowouts. (Usually scrap ends reused for such purpose.)
3. Sheets of cardboard or similar material used to preserve or display books, magazines, art prints, etc.
   • Campos likes this shop not only because it's just a few blocks from his Glendale home but because of the little extras that Brown throws in, like wrapping each comic book with a backer board in a plastic protective sleeve.2006 May 6, Angela Rabago-Mussi, “Drawn to comics gets your spidey senses tingling”, in Arizona Republic, Phoenix, Arizona, page 10