Home E Products E Surface Preparation E Crack Isolation Membranes E SIM-40 40 mil. Crack Isolation Membrane

  • 225 sq.ft. per roll, 20 rolls per pallet

PROFLEX® MAXXIM SIM-40 is a 40 mil composite underlayment consisting of a rubberized membrane laminated to a high strength reinforcing fabric on the face and a release sheet on the adhesive side. PROFLEX® MAXXIM SIM-40 is specially designed to be used under approved thinsets, mortars, and adhesives for interior and exterior applications of ceramic tile, stone, and brick, and for interior applications of wood flooring to eliminate the transmission of cracks. Other applications also may be suitable. Contact Technical Support for further information. To eliminate cracks in finished floor work, the product should be applied to the entire substrate prior to the installation of the finished flooring.


  • Easy and fast to install with standard tools
  • Ready for tiling immediately after installation
  • Crack and joint isolation up to 3/8″
  • Moisture Vapor Protection up to 5# per 1000 sq.ft/24 hr *CaCl2 Test (see installation instructions)
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