backerboard

plural backerboards · alternative backer board

1. A board used behind or under other material, often as support.
   1. countableuncountablebusinessBoards 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

      3 more examples

      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

      There are all sorts of different tile backer board products out there. Some are cement-based, some are gypsum-based, and others have a mix of ingredients.

      2007 February 25, Tim Carter, “For backer board, cement worth effort”, in The Record, Bergen County, NJ, page R4

      Dear Tim: What you call backerboard might be something entirely different from what I call backerboard. I'm quite concerned that you don't really have a waterproof backerboard since you said it crumbled. Technically, you have a board that is backing up tile, so I guess you can call it backerboard.

      2015 February 15, Tim Carter, “If it's gypsum, it's not good backerboard for tile”, in Telegraph-Herald, Dubuque, Iowa, page E8

   2. countableuncountableartsA 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. countableuncountableSheets 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