Gravity Cavity™

Economical Rainscreen Drainage Plane

GC 1816, GC 1832
Product made with a minimum 94% post industrial recycled plastic Made with a minimum 94% Post-Industrial Recycled Plastic

Gravity Cavity™ rainscreen drainage plane (drainage mat) is the economy alternative to our Sure Cavity® drainage plane (drainage mat) product.  It works because it maintains a separation between the materials used for the veneer and the structural back-up wall to drain incidental moisture and dry out the building enclosure.  Gravity Cavity™ drains and dries better than mesh-based drainage matrix products because its 1/8” deep channels enable moisture that enters the building envelope to travel quickly straight down and out the bottom of the wall, and it won’t compress behind siding.

Features & Benefits

  • True channels conduct moisture to the bottom of walls faster than other rainscreen drainage mat products
  • High impact polystyrene ensures durability and prevents compression, waviness, and nail drive-through experienced with fiber-based mesh products
  • Saves installation time (half the time of furring strips and backer board)
  • 96% pre-consumer recycled content
  • The adhered fabric blocks mortar or stucco from filling the drainage channels and acts as a bug screen at the bottom

Protection from Incidental Moisture behind

  • Stucco
  • Thin Stone & Thin Brick
  • Fiber Cement & Cedar Siding
  • Brick
  • Natural Stone

Gravity Cavity™ Installation

  • Roll out Gravity Cavity™ rainscreen drainage plane/drainage mat over the WRB on the backup wall with spunbond fabric facing the weather. Back wrap 4″ fabric on bottom course to act as bug screen.
  • Temporarily attach Gravity Cavity™ rainscreen drainage plane/drainage mat with hammer stapler on wood backup walls or dabs of adhesive on masonry.
  • Roll out second and succeeding courses of Gravity Cavity™.  Overlap only the fabric.  Plastic butts directly to top of course beneath it.
  • Install veneer – attachment of veneer material will sandwich the Gravity Cavity™ drainage mat permanently in place in thin veneer applications.

Ordering & Shipping

Contact MTI at 1-800-879-3348 for specific cost to your destination.

Gravity Cavity Specifications

GC 1816 and GC 1832 are 0.024″(0.6mm) thick, high impact polystyrene sheets. They are formed with corrugations and a spunbond polypropylene fabric on one side with a 4″ (102mm) skirt on one edge.

Product Number
GC 1816
GC 1832
Square Feet per Roll
Roll Length (Feet)
Roll Width (Inches)
Channel Depth
Rolls per Pallet
Square Feet per Pallet
Pallet Size

Documents, Specs, Details & More

L & R Weep Screed™

 LR 3501 

Wall Opening Weeps™

 WOW 9095