In masonry cavity walls, mortar collection above the flashing and weep hole levels is vital for proper masonry wall performance and to prevent water damage. In today’s walls, it’s common to see a 2” cavity reduced to the minimum requirement of 1” with the inclusion of insulation, so the need for better ventilation is essential to keep the wall dry and trouble-free. MortarNet WallDefender suspends mortar droppings above the flashing and weeps, so they stay clear and unobstructed. Its NEW design using a structural strand polymer mesh allows moisture to flow to the weeps and significantly greater airflow within the cavity to promote drying.


  • Dual levels
  • Trapezoidal shape
  • Structural strand polymer mesh
  • Made from 40% post-consumer recycled content
walldefender base
MortarNet WallDefender cavity wall drainage mesh available in ⅜", 1", 1½" and 2"


  • Compressible to allow for variations in cavity width
  • A cost competitive alternative to MortarNet™ with Insect Barrier
  • Breaks up and suspends mortar droppings above the flashing on two levels so weeps stay open
  • Structural strand polymer mesh construction provides hundreds of pathways for moisture to exit the cavity
  • Is very permeable to air, water and water vapor due to the low fiber density of the non-woven structure
  • Helps prevent efflorescence and damage from freeze-thaw cycles
  • Easy to transport, handle and cut, even on scaffolding
  • Installs easily on brick ties in multi-story cavity walls
  • Will not degrade, oxidize, or react with common building materials
  • Clean and non-toxic
  • Recycled content helps with LEED certification
  • Helps eliminate callbacks to repair moisture damage
  • Provides masons and building owners with a greater peace of mind

Weep holes must be used with MortarNet WallDefender to allow effective moisture drainage and wall drying.  Click on WeepVent or CellVent to see how they can help keep weep holes open and prevent insects from entering the cavity through the weeps.


walldefender window head
MortarNet WallDefender installed in window head