Type VIII Technical Data
Since 1988, Benchmark Foam has operated on a simple promise: to set the standard for quality and service in our industry. Our Type VIII Expanded Polystyrene (EPS) is a testament to this promise, offering a balanced profile of thermal performance and mechanical strength for demanding insulation applications. This cost-effective, durable and energy-efficient solution is engineered for projects that require reliable performance under pressure, making it an excellent choice for perimeter insulation, retaining structures and various geotechnical uses.
We construct our products to meet rigorous industry standards like ASTM C578, but our dedication to quality means we consistently push beyond these benchmarks. Type VIII EPS provides a dependable combination of insulation power and structural integrity, giving you a firm foundation for your most important projects.
Detailed Properties of Type 8 EPS
The following table outlines the complete physical properties of our Type VIII EPS, providing the definitive data you need for your specifications and designs.
This thermal resistance helps create energy-efficient building envelopes and contributes to lower heating and cooling costs and improved comfort in both residential and commercial structures.
| Nominal Density ASTM C303 | lb/ft3 | 1.5 | |
| Density, min. ASTM C303 | lb/ft3 | 1.35 | |
| R-Value1 Thermal resistance per 1.0 in thickness ASTM C518 | 25°F | °F·ft2·h/Btu | 4.76 |
| 40°F | °F·ft2·h/Btu | 4.55 | |
| 75°F | °F·ft2·h/Btu | 4.17 | |
| k-Value1 Thermal conductivity ASTM C518 | 25°F | Btu·in/°F·ft2·h | 0.217 |
| 40°F | Btu·in/°F·ft2·h | 0.227 | |
| 75°F | Btu·in/°F·ft2·h | 0.250 | |
| Compressive Strength @ 10% deformation, min. ASTM D1621 | psi | 15 | |
| Flexural Strength, min. ASTM C203, Procedure B | psi | 35 | |
| Water Vapor Permeance of 1.0 in. thickness, max., perm ASTM E96 | 3.5 | ||
| Water Absorption by total immersion, max., volume % ASTM C272 | <2.0 | ||
| Oxygen Index, min., volume % ASTM D2863 | 24 | ||
| Maximum recommended long-term exposure temperature | 167°F | ||
| Flame Spread ASTM E84 | <20 | ||
| Smoke Development ASTM E84 | 300 | ||
Understanding the Numbers
Strength for Structural Applications
The mechanical strength of EPS is directly linked to its density. Type VIII EPS is designed to handle significant loads, making it a superb choice for installations under concrete slabs and in foundation systems. This resilience allows the material to provide a stable, firm base that resists deformation over the lifetime of the structure, helping to minimize settling and maintain integrity. Its flexural strength further ensures it can withstand bending forces during and after installation.
Effective Moisture Management
Like all grades of EPS, Type VIII features a closed-cell structure that provides strong moisture resistance, which helps prevent mold growth and preserves a healthy building environment. While EPS is not a vapor barrier, its structure allows it to “breathe,” which can help prevent moisture accumulation within wall assemblies. This breathability eliminates the need for costly venting that other insulation materials might require.
Downloadable data sheet
The Reliable Choice for Demanding Projects
Choosing Benchmark Foam’s Type VIII EPS means selecting a material that brings together proven thermal performance, enhanced load-bearing capacity and dependable moisture resistance. Its balanced property profile makes it a versatile and intelligent solution for your structurally demanding applications.
We are serious about our customers, our products and our promises. Our team diligently strives to surpass our own standards every day and a quick, helpful response is our guarantee.
Ready to build with confidence? Contact Benchmark Foam today to discuss how Type VIII EPS can provide the proven performance your next project requires.