Trim Boards & Sheets Siding Accessories Products > Trim Boards & Sheets > Siding Accessories Boral Backer Board 3/8″ x 15″ x 48″; covers 105 square ft. Boral Backer Board quantity Add to Quote SKU: BACKERBOARD Category: Siding Accessories Related products BearSkin Joint Flashing Add to Quote 1 x 3 Hardie Prefinish Batten Strips Add to Quote