Polymer Modified System – (PM) (no longer permitted on Moisture Sensitive Substrates without WRB; however, still permitted on concrete and masonry substrates)
The polymer modified system components include:
- Extruded Polystyrene
- Mechanically Attached Mesh – (not shown)
- Heavy Weight Mesh – A More Open Weave Mesh vs Standard PB Mesh
- Plastic or Metal Trim Accessories – (not shown)
- 1/4″ – 3/8″ Base Coat
Polymer Modified System – (PM)
- Substrate
- System manufacturer approved rigid insulation
- Mechanical fasteners – 1/3 are used to attach the XEPS, the other 2/3 are used to attach the mesh
- 1/4″ – 3/8″ PM stucco
- Fiberglass reinforcing mesh (See 3. Above for fastener requirements.)
This drawing shows how a polymer-modified system is attached with mechanical fasteners.
PM over Framed Wall
This drawing shows how a polymer-modified system is attached to a framed wall.
PM over Masonry
This drawing shows how a polymer-modified system is attached to a masonry wall.
Key Points – (PM)
- Follow similar design patterns as a stucco system to control cracking and expansion. Reinforcing is fastened through the mesh or lath.
- Materials used in a class PM EIFS assembly are typically more per square foot than a standard class PB EIFS.
- Labor cost associated with class PM EIFS are higher than PB EIFS.
- Provides high insulation and excellent surface damage resistance.
- Requires an above average skilled EIFS craftsman