Wall and Foundation Applications

Styroshield is a closed cell, resilient lightweight, foamed plastic which has a compressive strength between 10-30 psi for most construction applications. Within that range Styroshield can be molded to meet specific application requirements.

Applied in roofing, foundations and walls, EPS has a successful history of efficient use in industrial, commercial, residential and cold storage buildings. Where enegy efficiency and cost-effectiveness have long been primary design considerations, architects have made EPS the dominant thermal insulation.

Long-term Insulation Value

The R-value of EPS insulation is permanent because the cellular structure of EPS contains only stabilized air. Its R-value will not decrease as it ages.

Moisture Resistance

Though it has low water vapor transmissions, EPS is not a vapor barrier. Rather it “breathes”, and therefore needs no costly venting as do some other relatively impermeable insulation materials which could other-wise trap moisture within walls and roof assemblies.

Temperature Cycling

EPS is able to withstand the abuse of temperature cycling, assuring long-term performance. In a series of tests conducted by Dynatech Research and Development Co., Cambridge, Mass., core specimens removed from existing freezer walls, some as old as 16 years, prove that EPS withstands freeze thaw cycling without loss of structural integrity or other physical properties.


EPS insulation is an inert, organic material. It provides no nutritive value to plants, animals or micro-organisms. It will not rot, and is highly resistant to mildew.

Strength Characteristics

For foundation and wall applications in which EPS bears a minimal load, nominal 1.0lb/ft3 density material is adequate. The resilience of EPS insulation board provides reasonable absorption of building movement without transferring stress to the outer skins at the joints.

If greater rigidity and strength are needed, compressive strengths up to 30 psi are available.

Standards Compliance

EPS insulation may be manufactured to meet or exceed the requirements of major model building codes, *ASTM C578, HUD Use or materials Bulletin #71, and DOE/RCS Standards.
*This standard supercedes Federal Specifications HH-I-524B, HH-I-524C

Fabrication and Installation

EPS insulation can be installed quickly and easily. It can be cut to shape with ordinary tools to assure a tight fit and to eliminate heat loss channels. Also, its light weight allows easy handling and storage.

Cost Efficiency

EPS insulation typically costs less than other rigid board insulations when compared on the basis or R-value.

Exterior Sheathing

– Meets or exceeds current energy conservation design standards without increasing stud width.
– Reduces air infilteration and heat loss through framing; slows convective looping.
– Corner bracing required for non-structural sheathing.
– Eliminates need for extra-deep framing
– Inside 1/2″ Drywall Required

Retrofit Insulation

– Supplements existing insulation to counter rising fuel cost.
– Easily applied during modernization or remodeling.
– Use a variety of siding or finishes.

Exterior Foundation Walls

– EPS may be attached with spot adhesive
– Cover exposed, above-grade EPS insulation with suitable protective exterior coating.
– Provides protections to water-proofing treatment.

Interior Foundation Walls

– For heated crawl spaces and basement areas.
– Supplements batt insulation between floor joists.
– Apply a suitable thermal barrier, such as 1/2″ gypsum board, to wood furring, z-furring or thermal studs.

Drywall Base

– Provides self-furring solid base for adhesive application of gypsum board.
– Supplementary furring recommended for integrity of gypsum board thermal barrier.
– EPS attached to masonry wall with adhesive, mechanical fasteners, z-furring or thermal studs.


As with organic materials, products manufactured from expandable polystyrene must be considered “combustible” when directly exposed to fire.

PROPERTY Units ASTM test type I type VIII type II type IX
DENSITY Nominal pcf C303 or D1622 1.00 1.25 1.50 2.00
THERMAL at 25° at 1 inch 4.35 4.54 4.76 5.00
RESISTANCE at 40° thickness 4.17 4.25 4.55 4.76
at 75° 3.85 3.92 4.17 4.35
Compressive 10% deformation psi D1621 10-14 13-18 15-21 25-33
Flexural psi C203 25-30 30-38 40-50 50-75
Tensile psi D1623 16-20 17-21 18-22 23-27
Shear psi D732 18-22 23-25 26-32 33-37
Shear Modulus psi 280-320 370-410 460-500 600-640
Modulus of Elasticity psi 180-220 250-310 320-360 460-500
Absorption perm. in E96 2.0-5.0 1.5-3.5 1.0-3.5 0.6-2.0
% vol. C272 less than less than less than less than
2.5 2.5 2.0 1.0
COEFFICIENT OF THERMAL in./(in.)(°F) D696 0.000035 0.000035 0.000035 0.000035
DENSITY Minimum pcf C578 0.9 1.15 1.35 1.80