Dryvit's Backstop Flash and Fill is designed to fill sheathing joints up to 1/2 in. and is used to provide an effective water-resistant transition membrane. Backstop Flash & Fill provides continuity of the Dryvit Backstop NT air and water-resistive barrier across various substrate materials (refer to data sheets, DS455, Backstop NT and Backstop NT for use beneath claddings other than Dryvit's EIFS.