XPS Foam Core
ASTM C578 · GB GB/T 10801.2
XPS Foam Core is extruded closed-cell polystyrene board classified to ASTM C578 (Types X, IV, VI, VII and V), with FR-B1, CO2-blown and HFO-blown variants.
Reference datasheet — XPS Foam Core is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the C578-IV condition
XPS Foam Core grades and fills
XPS Foam Core is supplied in 8 conditions, soft to hard. C578-IV is the default FabDigit quotes; the values on this page are for it.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
ASTM C578 Type X | Cheapest, lightest XPS for pure insulation or very lightly loaded sandwich skins. | 0.25 | 0.28 | 2.5 | |
Flame-retardant grade | Mandatory grade for building envelopes and cold-store panels in China; polymeric brominated FR replaces HBCD. | 0.34 | 0.38 | 2.5 | |
CO₂ / co-blown grade | Pick where HFC blowing agents are banned; slightly higher lambda than HFC/HFO boards. | 0.34 | 0.38 | 2.5 | |
C578-IVDefault ASTM C578 Type IV | Default construction/sandwich grade — best balance of price, strength and lambda. | 0.36 | 0.4 | 3 | |
HFO-blown high-R grade | Lowest thermal conductivity XPS with low-GWP blowing agent; premium price. | 0.36 | 0.4 | 3 | |
ASTM C578 Type VI | Choose for floor slabs, plaza decks and sandwich panels with moderate face pressure. | 0.45 | 0.5 | 3 | |
ASTM C578 Type VII | For loaded floors, cold-store bases and cores that must carry higher crush loads. | 0.54 | 0.6 | 3 | |
ASTM C578 Type V | Highest-density XPS for runways, heavy-load floors and structural sandwich cores. | 0.76 | 0.85 | 3.5 |
What is XPS Foam Core?
XPS Foam Core is extruded closed-cell polystyrene board classified to ASTM C578 (Types X, IV, VI, VII and V), with FR-B1, CO2-blown and HFO-blown variants. At 0.03 g/cm³ it gives 0.4 MPa tensile strength, 0.011 GPa modulus, 0.029 W/m·K conductivity and 75 °C service temperature, with far lower water absorption than EPS, so it is used in insulated roof and wall panels, cold-chain panels and hobby composite cores. It comes only as extruded board in set thicknesses, the extrusion skin must be sanded off before bonding, and styrene or solvent-based resins attack it — use epoxy or PU. SAN or PVC foam is the step up where shear strength governs. XPS Foam Core has a density of 0.03 g/cm³ (0.0011 lb/in³), lighter than 99% of composite grades. Its glass-transition temperature is 100°C (212 °F). XPS Foam Core has a yield strength of 0.36 MPa (0.0522 ksi) and a tensile strength of 0.4 MPa (0.058 ksi) — weaker than 100% of composite grades. Elongation at break is 3% and the elastic modulus is 0.01 GPa (0.0016 Msi).
What is XPS Foam Core used for?
- insulated roofing/wall sandwich panels
- cold-chain panels
- DIY composite core stock
Advantages
- Lightweight — 0.03 g/cm³ (0.0011 lb/in³), better than 99% of composite grades
- Easy to machine — 88/100, better than 93% of composite grades
- Low embodied carbon — 4.2 kg CO₂/kg, better than 88% of composite grades
- Good corrosion resistance — 90/100, better than 85% of composite grades
- Low moisture uptake — 0.1%, better than 85% of composite grades
Limitations
- Low strength — 0.36 MPa (0.0522 ksi), worse than 100% of composite grades
- Poor heat conductor — 0.03 W/m·K (0.0168 BTU/hr·ft·°F), worse than 99% of composite grades
- Low stiffness — 0.01 GPa (0.0016 Msi), worse than 98% of composite grades
- Limited service temperature — 75°C (167 °F), worse than 96% of composite grades
- Degrades in UV without stabilisers — 20/100, worse than 94% of composite grades
XPS Foam Core properties
Typical room-temperature values for XPS Foam Core-C578-IV; bars are the position among composite grades.
Physical4
XPS Foam Core has a density of 0.03 g/cm³ (0.0011 lb/in³), lighter than 99% of composite grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical11
XPS Foam Core has a yield strength of 0.36 MPa (0.0522 ksi) and a tensile strength of 0.4 MPa (0.058 ksi) — weaker than 100% of composite grades. Elongation at break is 3% and the elastic modulus is 0.01 GPa (0.0016 Msi).
Thermal8
XPS Foam Core is rated for continuous service to 75°C (167 °F). It conducts heat at 0.03 W/m·K (0.0168 BTU/hr·ft·°F), worse than 99% of composite grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical3
XPS Foam Core has an electrical resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 85% of composite grades. UV resistance is poor.
Sustainability3
Producing a kilogram of XPS Foam Core takes about 100 MJ of energy and emits 4.2 kg of CO₂ — less than 67% of composite grades. Typical recycled content is 10%.
Manufacturability1
XPS Foam Core's machinability is excellent (88/100, better than 93% of composite grades).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. XPS Foam Core is highlighted; hover a dot for its name, or open the interactive family chart.
Working with XPS Foam Core
Is XPS Foam Core easy to machine?
Cuts cleanly with hot wire, knife, band saw or CNC router; use sharp tools, low feed pressure and vacuum extraction — static-charged dust sticks to everything.
Can XPS Foam Core be welded?
Not weldable in the metal sense; panels are joined by shiplap/tongue-and-groove joints and PS-compatible adhesives (water-based, PU or epoxy) — never solvent-based or polyester resin.
Can XPS Foam Core be formed, bent or molded?
Supplied as extruded board only; thermoforming is impractical — shape by cutting, grooving or CNC contouring, and add scrim/skin coats before laminating.
XPS Foam Core chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| blowing agent (CO2 / HFC-134a / HFO-1234residual cell gas | 1.5 – 6 | 3 |
| flame retardant (polymeric brominated, eB1/E84 grades only | 0.5 – 3 | 1.5 |
| talc / nucleating agentcell-size control | 0.2 – 1.5 | 0.6 |
| pigment & processing aids | 0.1 – 1 | 0.3 |
| polystyrene (GPPS/recycled PS)matrix resin | ≥ 92 (balance) |
What surface finishes work on XPS Foam Core?
Bond FRP, cement board or metal facings with epoxy/PU; skin the surface or cover within a few weeks since UV rapidly chalks and embrittles the outer cells.
Equivalent designations
Standards and trade names that resolve to XPS Foam Core in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- C578
- GB (China)
- GB/T 10801.2
How much does XPS Foam Core cost?
XPS Foam Core is a standard-cost composite ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
XPS Foam Core — frequently asked
What is XPS Foam Core used for?
XPS Foam Core is typically used for insulated roofing/wall sandwich panels, cold-chain panels and DIY composite core stock. In short: stronger and drier than EPS; board stock only; low-cost insulating core.
What is the yield strength of XPS Foam Core?
XPS Foam Core has a typical yield strength of 0.36 MPa (0.0522 ksi) and a tensile strength of 0.4 MPa (0.058 ksi) — weaker than 100% of composite grades. Strength varies by condition: see the 8 listed tempers.
Is XPS Foam Core easy to machine?
Yes — machinability is rated excellent (88/100, better than 93% of composite grades). Cuts cleanly with hot wire, knife, band saw or CNC router; use sharp tools, low feed pressure and vacuum extraction — static-charged dust sticks to everything.
Can XPS Foam Core be welded?
Not weldable in the metal sense; panels are joined by shiplap/tongue-and-groove joints and PS-compatible adhesives (water-based, PU or epoxy) — never solvent-based or polyester resin.
What surface finishes work on XPS Foam Core?
Bond FRP, cement board or metal facings with epoxy/PU; skin the surface or cover within a few weeks since UV rapidly chalks and embrittles the outer cells.
Can XPS Foam Core be formed, bent or molded?
Supplied as extruded board only; thermoforming is impractical — shape by cutting, grooving or CNC contouring, and add scrim/skin coats before laminating.
What is the maximum service temperature of XPS Foam Core?
XPS Foam Core is rated for continuous use to about 75°C (167 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between XPS Foam Core C578-IV and XPS Foam Core C578-V?
C578-IV is the default condition — default construction/sandwich grade — best balance of price, strength and lambda. C578-V: highest-density XPS for runways, heavy-load floors and structural sandwich cores. Yield strength is 0.36 MPa in C578-IV versus 0.76 MPa in C578-V.
How much does XPS Foam Core cost?
XPS Foam Core is a standard-cost composite ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM C578 Standard Specification for Rigid Cellular Polystyrene Thermal Insulation — ASTM International (2022)
- FOAMULAR XPS insulation product data — Owens Corning (2023)
- STYROFOAM Brand XPS technical data — Dow / DuPont Performance Building Solutions (2022)
- Rigid polystyrene foam property records — CES EduPack / Granta (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.