XPS 300 GR
Additive grade
EN 13164 XPS300
GR = graphite / IR-absorber enhanced grey board
Use where a slightly lower lambda is wanted with conventional CO₂ blowing; grey-coloured core from IR absorber.
Values for the GR condition
Other XPS 300 grades and fills
XPS 300 is listed in 6 conditions; see the grade overview at XPS 300.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Grooved/channelled perimeter drainage board | Use against basement walls where the board must also drain water and protect the waterproofing membrane. | 0.28 | 0.4 | 3 | — |
High recycled-PS content board | Choose for EPD/green-building credits; uses post-industrial and post-consumer PS regrind in the core. | 0.29 | 0.4 | 2.5 | — |
STD-CO2Default STD-CO₂ | Default HFC-free board for below-grade walls, floors and inverted roofs where λ 0.033–0.036 is sufficient. | 0.3 | 0.45 | 3 | — |
HFO/low-GWP blowing agent, low-lambda board | Pick when U-value targets need λ ≈ 0.028–0.030 in limited thickness, e.g. thin perimeter or inverted-roof build-ups. | 0.3 | 0.45 | 3 | — |
GRThis page Graphite / IR-absorber enhanced grey board | Use where a slightly lower lambda is wanted with conventional CO₂ blowing; grey-coloured core from IR absorber. | 0.3 | 0.44 | 2.8 | — |
Polymeric (HBCD-free) flame retardant, Euroclass E | Current EU-compliant FR chemistry (brominated styrene-butadiene polymer) replacing HBCD; required for REACH/POP compliance. | 0.3 | 0.43 | 2.8 | — |
What is XPS 300 GR?
XPS 300 GR is XPS 300 in the GR grade — use where a slightly lower lambda is wanted with conventional CO₂ blowing; grey-coloured core from IR absorber. XPS 300 GR has a yield strength of 0.3 MPa (0.0435 ksi) and a tensile strength of 0.44 MPa (0.0638 ksi) — weaker than 97% of polymer grades. Elongation at break is 2.8% and the elastic modulus is 0.02 GPa (0.0022 Msi). XPS 300 GR has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 91% of polymer grades. Its glass-transition temperature is 100°C (212 °F). STD-CO2 is the default condition FabDigit quotes; GR is available on request or by drawing note.
Advantages
- Easy to machine — 90/100, better than 95% of polymer grades
- Lightweight — 0.04 g/cm³ (0.0013 lb/in³), better than 91% of polymer grades
- Low embodied carbon — 3.2 kg CO₂/kg, better than 81% of polymer grades
Limitations
- Low strength — 0.3 MPa (0.0435 ksi), worse than 97% of polymer grades
- Poor heat conductor — 0.03 W/m·K (0.0179 BTU/hr·ft·°F), worse than 96% of polymer grades
- Degrades in UV without stabilisers — 15/100, worse than 95% of polymer grades
- Limited formability — 10/100, worse than 87% of polymer grades
- Limited ductility — 2.8%, worse than 86% of polymer grades
XPS 300 GR properties
Typical room-temperature values for XPS 300 GR; 18 are specific to this condition. Other listed values are XPS 300 reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
XPS 300 GR has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 91% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical10
XPS 300 GR has a yield strength of 0.3 MPa (0.0435 ksi) and a tensile strength of 0.44 MPa (0.0638 ksi) — weaker than 97% of polymer grades. Elongation at break is 2.8% and the elastic modulus is 0.02 GPa (0.0022 Msi).
Thermal9
XPS 300 GR is rated for continuous service to 75°C (167 °F). It conducts heat at 0.03 W/m·K (0.0179 BTU/hr·ft·°F), worse than 96% of polymer grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical3
XPS 300 GR has an electrical resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of XPS 300 GR takes about 100 MJ of energy and emits 3.2 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 15%.
Manufacturability4
XPS 300 GR's machinability is excellent (90/100, better than 95% of polymer grades); weldability poor (15/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with XPS 300 GR
Is XPS 300 easy to machine?
Cuts cleanly with a utility knife, hot-wire, fine-tooth handsaw or CNC router; use dust extraction and avoid melting/smearing from high-speed tooling.
Can XPS 300 be welded?
Not weldable in a structural sense; boards are joined mechanically (shiplap/T&G) or with solvent-free PU or cement-based adhesives.
Can XPS 300 be formed, bent or molded?
Produced by continuous tandem extrusion foaming and cut to size — no post-forming; can be thermally curved only slightly, so profiles are machined not bent.
What surface finishes work on XPS 300?
Must be protected from UV and solvents: cover with render on planed/embossed faces, cement board, backfill or ballast; use only solvent-free bitumen and adhesives.
XPS 300 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 / HFO-1234ze / co-bloresidual after extrusion foaming | 1 – 5 | 3 |
| brominated polymeric flame retardantHBCD-free polymeric FR in current EU production | 0.5 – 2 | 1 |
| talc (nucleating agent) | 0.2 – 1 | 0.5 |
| pigment / IR absorber (graphite in grey | 0 – 1.5 | 0.3 |
| polystyrene (PS homopolymer, incl. regrimatrix resin | ≥ 90 (balance) | — |
XPS 300 GR — frequently asked
What is XPS 300 GR used for?
XPS 300 GR is typically used for below-grade (perimeter) wall insulation, inverted roof insulation, under-slab and foundation insulation, frost protection for foundations and pavements, insulated render substrates on planed board and cold store wall and floor panels. In short: standard below-grade XPS; low water absorption board; 300 kPa compressive class.
What is the yield strength of XPS 300 GR?
XPS 300 GR has a typical yield strength of 0.3 MPa (0.0435 ksi) and a tensile strength of 0.44 MPa (0.0638 ksi) — weaker than 97% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is XPS 300 GR easy to machine?
Yes — machinability is rated excellent (90/100, better than 95% of polymer grades). Cuts cleanly with a utility knife, hot-wire, fine-tooth handsaw or CNC router; use dust extraction and avoid melting/smearing from high-speed tooling.
Can XPS 300 GR be welded?
Not readily — weldability is rated poor (15/100). Not weldable in a structural sense; boards are joined mechanically (shiplap/T&G) or with solvent-free PU or cement-based adhesives.
What surface finishes work on XPS 300 GR?
Must be protected from UV and solvents: cover with render on planed/embossed faces, cement board, backfill or ballast; use only solvent-free bitumen and adhesives.
Can XPS 300 GR be formed, bent or molded?
Produced by continuous tandem extrusion foaming and cut to size — no post-forming; can be thermally curved only slightly, so profiles are machined not bent.
What is the maximum service temperature of XPS 300 GR?
XPS 300 GR 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 300 STD-CO2 and XPS 300 DRAIN?
STD-CO2 is the default condition — default HFC-free board for below-grade walls, floors and inverted roofs where λ 0.033–0.036 is sufficient. DRAIN: use against basement walls where the board must also drain water and protect the waterproofing membrane. Yield strength is 0.3 MPa in STD-CO2 versus 0.28 MPa in DRAIN.
Sources
- EN 13164:2012+A1:2015 — Thermal insulation products for buildings: factory made extruded polystyrene foam (XPS) — CEN (2015)
- EN 826 / EN 12087 / EN 12089 / EN 12667 test methods for rigid insulation — CEN (2013)
- ASTM C578 — Rigid Cellular Polystyrene Thermal Insulation — ASTM (2022)
- XPS board technical datasheets / CE-DoP (Austrotherm, URSA, Ravago, Soprema, Styrofoam) — various (2024)
- Inventory of Carbon & Energy (ICE) and European XPS EPDs — Circular Ecology / EXIBA (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.