Yes, certain types of styrofoam, specifically high-density Expanded Polystyrene (EPS) foam, can be effectively used as a base or sub-surface material under pavers. This application is particularly common in specific construction scenarios where its unique properties offer significant advantages.
Understanding "Styrofoam" in Construction
While "Styrofoam" is a widely recognized brand name for extruded polystyrene (XPS) foam, in construction, the term often broadly refers to both XPS and Expanded Polystyrene (EPS) foam. For structural applications under pavers, high-density EPS foam (often referred to as geofoam) is the more common and suitable choice due to its manufacturing process which allows for a wider range of densities and compressive strengths.
Key Considerations for Using High-Density EPS Foam Under Pavers
The suitability of EPS foam depends heavily on its specifications and the specific application.
Compressive Strength is Crucial
For any material used beneath pavers, especially under concentrated loads, its ability to withstand compression without deforming is paramount. High-density EPS foam is engineered to provide substantial compressive strength. For instance, materials with a compressive strength of 60 psi (pounds per square inch) are recommended for use under paver pedestals. This is because pedestals create concentrated point loading, requiring a robust material to prevent settlement or damage to the underlying structure. This type of foam can be used to raise the sub-surface below various paver types, including concrete and wood roof pavers.
Benefits of High-Density EPS Foam
When used appropriately, high-density EPS foam offers several advantages:
- Lightweight: Its light weight significantly reduces the load on structures, which is particularly beneficial for elevated applications like roof decks or balconies. This can lead to cost savings in structural design.
- High Compressive Strength: Engineered to withstand significant loads, preventing settling or deformation under the weight of pavers and foot traffic.
- Moisture Resistance: EPS foam is largely resistant to moisture absorption, which helps maintain its structural integrity and insulating properties over time.
- Insulation: Provides thermal insulation, which can be an added benefit for roof decks or areas where temperature control is desired.
- Ease of Installation: Large, lightweight blocks are easy to cut and position, simplifying the installation process and reducing labor costs.
- Drainage: Can be designed to facilitate drainage, preventing water accumulation under the pavers.
When is High-Density EPS Foam Used Under Pavers?
EPS foam is typically employed in specific construction scenarios, including:
- Roof Decks and Elevated Patios: Where minimizing weight is critical, EPS foam replaces heavier traditional fill materials like gravel or soil.
- Raising Sub-Surfaces: To achieve desired elevations or create slopes for drainage without adding excessive dead weight to the supporting structure.
- Under Pedestal Systems: Providing a stable, high-compressive base directly beneath paver pedestals, especially where concentrated loads are a concern.
- Areas Requiring Thermal Insulation: Combining structural support with insulating properties for energy efficiency.
Important Factors for Successful Installation
To ensure the successful use of EPS foam under pavers, consider the following:
- Consult Manufacturer Specifications: Always adhere to the EPS foam manufacturer's guidelines regarding compressive strength, density, and installation procedures.
- Structural Engineer Approval: For load-bearing applications, especially on elevated structures, a structural engineer's assessment and approval are crucial.
- Proper Drainage Design: Ensure the system incorporates adequate drainage to prevent water accumulation, which can undermine the paver system over time.
- Protection Layers: Depending on the application, a geotextile fabric or other protective layers may be required between the foam and the paver base material to prevent movement or wear.
In summary, while not suitable for all paver installations, high-density EPS foam is a viable and often superior choice for specific applications, particularly where weight, compressive strength, and insulation are critical factors.
