This guide answers six of the most frequently asked questions about THERMAX™ Polyiso Insulation and STYROFOAM™ XPS Insulation. With increased focus on building resiliency and compliance with code requirements, these insights address storage, mold prevention, flame spread ratings, and more.

How Should THERMAX™ (ci) Exterior Insulation Be Stored?

Proper storage ensures insulation remains effective and undamaged:

  • Avoid direct sunlight exposure for more than 180 days.
  • Store above standing water and tarp the product to protect it from weather.
  • If wet, allow the boards to air dry before covering.
  • Secure loose boards to prevent wind displacement.
  • Follow local fire and building codes, such as NFPA 230 for fire protection of storage and NFPA 13 for sprinkler system installation.

Related Question: How long can THERMAX™, TUFF-R™, and Super TUFF-R™ Polyiso Insulation remain exposed before covering? Up to 180 days under proper conditions.

Does STYROFOAM™ Brand XPS Insulation Promote Mold Growth?

STYROFOAM™ XPS Insulation products are resistant to mold and mildew due to their moisture-resistant closed-cell structure.

  • Proper insulation thickness prevents condensation, the main driver of mold growth.
  • By reducing moisture infiltration and keeping walls warmer, these products minimize mold potential.
  • Mold formation can still occur in poor construction, so follow proper installation and maintenance practices.

What Are the Flame Spread Rating Requirements for Foam Insulation in Canada?

STYROFOAM™ XPS Insulation products are resistant to mold and mildew due to their moisture-resistant closed-cell structure.

  • Residential Construction: No flame spread rating requirements.
  • Commercial Construction: Flame spread ratings must be under 500, per CAN/ULC S102.2 (for thermoplastic materials) or CAN/ULC S102 (for thermoset materials).
    Use the Canadian Code Assessment Engine for specific code comparisons and compliance strategies.

What Are the Effective System R-Values for the THERMAX™ Wall System?

The effective R-value depends on the thickness of insulation and the type of veneer:

 

Thickness (in) Effective R-Value
0.625 10.8
1.0 13.2
1.55 16.8
2.0 19.7
Adding a stucco veneer with a brick rain screen increases the R-value by ~1.7. Other veneers like terra cotta or metal panels may not affect R-values.

What Are the Densities of STYROFOAM™ XPS Insulation Products?

STYROFOAM™ insulation meets ASTM C578 standards for minimum density:

 

Type Density (pcf) Example Products
Type X 1.30 CAVITYMATE™, Residential Sheathing (RS)
Type IV 1.55 CAVITYMATE™ Plus, SCOREBOARD™
Type VI 1.80 HIGHLOAD 40, ROOFMATE™
Type VII 2.20 HIGHLOAD 60, PLAZAMATE™
Type V 3.00 HIGHLOAD 100
Density alone is not the sole criterion for product selection; consider performance properties like compressive strength.

What Are the Weights of THERMAX™ Polyiso Insulation Products?

The weights for 1-inch thickness (per square foot) are as follows:

 

Product Weight (lb/ft²)
THERMAX™ Light Duty 0.197
THERMAX™ Heavy Duty 0.216
THERMAX™ White Board 0.187
THERMAX™ Sheathing 0.150
THERMAX™ Metal Building 0.195
For a 4′ x 8′ board, multiply the weight per square foot by 32.

What To Know

From proper storage and flame spread requirements to effective R-values and density details, rigid insulation systems like THERMAX™ and STYROFOAM™ XPS are versatile, durable, and compliant with building standards. For customized insights and project-specific guidance, contact our building science experts.