C578 Type VI
ASTM C578 Type VI is a higher-density closed-cell extruded polystyrene (XPS) board in the ASTM C578 family, made by tandem extrusion with an injected blowing agent.
Reference datasheet — C578 Type VI 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.
C578 Type VI grades and fills
C578 Type VI is supplied in 3 conditions, soft to hard.
Compare all 3 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Grooved / channelled drainage board | Grooved face with bonded filter fabric for foundation walls, plaza decks and green roofs needing drainage. | — | 0.43 | 4 | — |
Low-GWP (HFO-1234ze) blown board | Choose for LEED/EPD projects and jurisdictions restricting HFC blowing agents; thermal and mechanical values essentially unchanged. | — | 0.48 | 4 | — |
Borate / insecticide-treated board | Below-grade and slab-edge use in termite-active regions where untreated foam is restricted by code. | — | 0.48 | 4 | — |
Supply forms, finishes and certifications
Ways C578 Type VI is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FACED | Film / foil / fabric faced board | Coating |
TG | T&G | Coating |
STDDefault | Unfaced XPS board, square edge | Standard supply |
What is C578 Type VI?
ASTM C578 Type VI is a higher-density closed-cell extruded polystyrene (XPS) board in the ASTM C578 family, made by tandem extrusion with an injected blowing agent. It is chosen where compressive strength must exceed Type IV, typically under parking and plaza decks, and is supplied plain, tongue-and-groove, drainage-grooved, faced, termite-treated and with HFO low-GWP blowing agent. Thermal conductivity is 0.029 W/m·K. Boards are rigid, cannot be cold-bent or post-formed, and must be kept out of UV, solvents and hot asphalt above about 80 °C; step up to Type VII where loads are heavier. C578 Type VI has a density of 0.03 g/cm³ (0.0011 lb/in³), lighter than 94% of polymer grades. Its glass-transition temperature is 100°C (212 °F). C578 Type VI has a tensile strength of 0.48 MPa (0.0696 ksi), weaker than 89% of polymer grades. The elastic modulus is 0.02 GPa (0.0026 Msi).
What is C578 Type VI used for?
- Parking deck insulation
- Plaza deck insulation
- Roadway insulation
Advantages
- Easy to machine — 92/100, better than 99% of polymer grades
- Lightweight — 0.03 g/cm³ (0.0011 lb/in³), better than 94% of polymer grades
- Low moisture uptake — 0.1%, better than 77% of polymer grades
Limitations
- Poor heat conductor — 0.03 W/m·K (0.0168 BTU/hr·ft·°F), worse than 98% of polymer grades
- Degrades in UV without stabilisers — 15/100, worse than 95% of polymer grades
- Limited formability — 15/100, worse than 79% of polymer grades
- Low stiffness — 0.02 GPa (0.0026 Msi), worse than 76% of polymer grades
C578 Type VI properties
Typical room-temperature values; bars are the position among polymer grades.
Physical4
C578 Type VI has a density of 0.03 g/cm³ (0.0011 lb/in³), lighter than 94% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical8
C578 Type VI has a tensile strength of 0.48 MPa (0.0696 ksi), weaker than 89% of polymer grades. The elastic modulus is 0.02 GPa (0.0026 Msi).
Thermal8
C578 Type VI is rated for continuous service to 74°C (165 °F). It conducts heat at 0.03 W/m·K (0.0168 BTU/hr·ft·°F), worse than 98% of polymer grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical2
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is poor.
Sustainability3
Producing a kilogram of C578 Type VI takes about 105 MJ of energy and emits 4.8 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 10%.
Manufacturability3
C578 Type VI's machinability is excellent (92/100, better than 99% of polymer grades); formability poor (15/100).
Common Calculations4
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 polymer family
Yield strength against density for every polymer grade FabDigit runs. C578 Type VI is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C578 Type VI
Is C578 Type VI easy to machine?
Cut with hot wire, sharp knife or fine-tooth blade at low speed; router/CNC works but generates static-clinging dust — vacuum extraction recommended.
Can C578 Type VI be welded?
Not weldable in the metal sense; joints are made with mechanical fasteners, tape or XPS-compatible (solvent-free) foam adhesive.
Can C578 Type VI be formed, bent or molded?
Produced by tandem extrusion with gas injection; boards are rigid and cannot be cold-bent — curved shapes are kerf-cut or hot-wire profiled.
C578 Type VI 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 / HFC-13residual gas in cells; sets aged R-value | 2 – 6 | 3.5 |
| flame retardant (polymeric brominated, preplaces legacy HBCD | 0.5 – 1.5 | 0.9 |
| nucleating agent (talc) + pigmentcell-size control and brand colour | 0.2 – 1.5 | 0.6 |
| polystyrene (GPPS/recycled PS)extruded closed-cell matrix | ≥ 92 (balance) | — |
What surface finishes work on C578 Type VI?
Skin can be scarified or grooved for plaster/EIFS adhesion; use only water-based or PU coatings and never solvent-based mastics or hot asphalt above ~80 °C.
How much does C578 Type VI cost?
C578 Type VI is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C578 Type VI — frequently asked
What is C578 Type VI used for?
C578 Type VI is typically used for parking deck insulation, plaza deck insulation and roadway insulation. In short: mid-load XPS board; plaza and parking deck grade; HFO low-GWP option.
What is the tensile strength of C578 Type VI?
C578 Type VI has a typical tensile strength of 0.48 MPa (0.0696 ksi) — weaker than 89% of polymer grades. Strength varies by condition: see the 3 listed tempers.
Is C578 Type VI easy to machine?
Yes — machinability is rated excellent (92/100, better than 99% of polymer grades). Cut with hot wire, sharp knife or fine-tooth blade at low speed; router/CNC works but generates static-clinging dust — vacuum extraction recommended.
Can C578 Type VI be welded?
Not weldable in the metal sense; joints are made with mechanical fasteners, tape or XPS-compatible (solvent-free) foam adhesive.
What surface finishes work on C578 Type VI?
Skin can be scarified or grooved for plaster/EIFS adhesion; use only water-based or PU coatings and never solvent-based mastics or hot asphalt above ~80 °C.
Can C578 Type VI be formed, bent or molded?
Produced by tandem extrusion with gas injection; boards are rigid and cannot be cold-bent — curved shapes are kerf-cut or hot-wire profiled.
What is the maximum service temperature of C578 Type VI?
C578 Type VI is rated for continuous use to about 74°C (165 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C578 Type VI cost?
C578 Type VI is a standard-cost polymer ($$), 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)
- ASTM C165 / C203 / C272 / C273 / D2863 (test methods referenced by C578) — ASTM International (2021)
- Extruded polystyrene 40 psi board technical data (Owens Corning FOAMULAR / DuPont Styrofoam class) — producer literature (2024)
- Handbook of Polymeric Foams and Foam Technology — polystyrene foam properties — Hanser (2004)
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.