The BlockNet CMU single wythe flashing solution reliably protects CMU walls from water infiltration damage by enabling moisture to easily drain from the block cell interiors to the building exterior.

Water in the block cells flows down the inside of the face of the cells through the BlockNet vertical mesh component and onto the horizontal stainless steel drainage section, which channels water out of the wall through the integrated horizontal drainage mesh element and drainage tabs.


  • Stainless steel drainage section collects moisture and channels it to the exterior of the building through the integrated 90% open weave weep tabs
  • 7″ x 7″ vertical mesh elements install in CMU block cells above the drainage section to allow moisture to flow around mortar droppings to the weep tabs
  • A rear dam on the drainage sections channels water to the weep tabs and out of the building
  • May be used in reinforced or unreinforced 8″, 10″, and 12″ walls
  • May be used with unreinforced 6″ walls


  • The only concrete block flashing solution that is Ideal for repair, restoration and high security projects as well as new construction
  • Helps prevent moisture damage such as efflorescence, staining and freeze/thaw damage caused by moisture in the block cores
  • Applicable in all flashing locations, including base of wall, parapet walls, and above bond beams, wall openings and structural steel members
  • Installs quickly and easily with minimal training
  • Can be installed in a fully grouted wall without affecting the reinforcing
  • Helps prevent costly call-backs, repairs and legal issues
  • Lightweight and easy to handle, even on high scaffolding
  • Shows a continuous stainless steel drip edge for a clean, unobtrusive appearance
  • Does not interfere with properly placed re-bar, and can easily be cut with tin snips to fit around improperly placed rebar
  • Mesh components are 40% recycled polyester and stainless steel components are 100% recyclable to help with LEED certification
  • Removable weep tab ends prevent tabs from clogging when joints are struck, keep tabs flush with the wall and create a smooth appearance
  • Will not degrade, promote mold or fungus growth, or react with common building materials
According to Robert Nelson of Robert L. Nelson & Associates, a nationally recognized masonry materials testing laboratory located in Schaumburg, Illinois “I have tested hundreds of walls over the years and moisture, even wind driven rain, will consistently run down the inside of the exterior face shell of the block. Moisture rarely penetrates beyond an inch inside the core.”
blocknet wall base
BlockNet installation at wall base
blocknet lintel sill
BlockNet installation in single wythe lintel and sill
BlockNet Product Overview