Schluter® DITRA Uncoupling Membrane — 3'3" × 98'5" (323 SF) Large RollThe 323 sq ft DITRA roll is contractor sized for large tile jobs open floor plans, full first floors, or commercial spaces. One roll covers a substantial area with minimal seaming, and the cost per square foot is better than smaller rolls. Same 1 8" (3. 5mm) polyethylene uncoupling membrane as all DITRA products dovetail cavities lock into thin set from both sides, preventing tile cracks caused by subfloor movement 33" wide x 98. 5' long (323 sq ft)