General Guidelines and Specifications for an Evaluated AAC Plastering System

 

 

1.0          General Guidelines for Mineral Type finishes

 

1.1               Compressive strength: As a rule of thumb, compressive strength should not exceed two times the compressive strength of AAC (<1000 psi). This requirement is necessary as system to reduce the differential movement between the coating and the substrate and cracking of the plaster. (Ext./Int.)

 

1.2               Modulus of Elasticity – Low value similar to AAC’s MOE is required to reduce stresses due to movement in the wall / floor systems. (Ext./Int.)

 

1.3               Aesthetic features – Like other finishing system, aesthetic and texture features are typically required / available for AACl approved exterior and interior systems. (Mainly Ext.)

 

1.4               Cost of system – an essential benefit for the complete AAC wall system. The exterior finish is designed to be applied as a one-coat system (3/8” – 7/16”) compared to multi-layers system stucco or EIFS. (Ext./Int. @ 3/16” – 1/4” depending on wall type)

 

1.5               Workability – Most approved exterior and interior plastering systems possess features such as light-weight, relatively low waste during application, excellent coverage per unit weight, and other workability enhancing additives. (Ext./Int.)

 

1.6               Durability – Most approved finishing systems are designed to have higher crack resistance and excellent bonding to AAC. (Ext./Int.)

 

1.7               Excellent resistance to moisture penetration. (Ext.)

 

1.8               Breathable Systems – Like all mineral-based coatings, vapor diffusion is higher than acrylic products. Hence, no condensation or moisture damages in the wall system. (Ext./Int.)

 

1.9               Required Specification / Documents

 

Property	Test Procedure
Compressive Strength	ASTM C109
Density	ASTM C188
Modulus of Elasticity	ASTM C580 (ACI 523.3R Formula)
Water Retention	ASTM C91
Vapor permeability	ASTM E96
Water Penetration	ASTM E514 or ASTM C413
Application sheet	Required
Product description	Required
Material Cost	Required

 

2.0           General Guidelines for Acrylic Coating / Paint

 

2.1               Aesthetic features – Like other finishing system, aesthetic and texture features are typically required / available for AACl approved exterior and interior systems.

 

2.2               Cost of system – an essential benefit for the complete AAC wall system.

 

2.3               Workability – Most approved exterior and interior plastering systems possess features such as relatively low waste during application and coverage

 

2.4               Durability

 

2.5               Excellent resistance to moisture penetration.

 

2.6               Breathable Systems with high vapor permeability

 

2.7               Required Specification / Documents

 

 

Property	Test Procedure
Vapor permeability	ASTM E96 (Min. 5)
Water Penetration	ASTM D1735 ASTM E331 Or equivalent with pass / fail criteria and quantified flow rate
Bonding and flexibility Properties	Required (psi)
Application sheet	Required
Product description	Required
Material Cost	Required

  SafeCrete provides a full line of mineral-based (Olde World) and acrylic stucco.