EIFS with Drainage Wall Assembly (from interior to exterior):
Interior Wall Structure
– Wood or metal studs with cavity insulation as needed.
Exterior Sheathing
– Gypsum, OSB, or plywood sheathing.
WRB / Air Barrier
– Fluid-applied or sheet membrane air and moisture barrier. (Required for drainage EIFS.)
Adhesive or Mechanical Attachment
– Adhesive (cementitious or polymer-based) or fasteners to secure foam board.
Insulation Board
– Typically expanded polystyrene (EPS), 1"–4" thick. (XPS or mineral wool may be used for higher performance or fire resistance.)
Reinforcing Mesh
– Alkali-resistant fiberglass mesh embedded in base coat.
Base Coat
– Cementitious or polymer-based base coat applied over the mesh.
Finish Coat
– Textured acrylic or synthetic finish coat, available in various colors and patterns.​For EIFS with Drainage (preferred in most modern installations):
Grooved EPS board or a wrinkled WRB layer helps form the drainage plane.
Starter track with weep holes at the base for water egress.
Backwrapping is required at all terminations to protect the EPS and maintain a seal.​Important EIFS System Notes:
EIFS is not a "3-coat stucco" — it's a distinct system with integrated insulation and synthetic finishes.
Must comply with ASTM E2568 (Standard Specification for EIFS).
Ensure all flashing and sealants are properly installed at terminations and penetrations.