BANARTA
Select XPS in three steps: calculate the thickness needed for insulation, choose the grade needed for loading, then specify the sheet size and surface for installation or fabrication. For the same thermal conductivity, a thicker layer gives more thermal resistance. A higher compression grade addresses a different requirement; neither foam colour nor board thickness tells you its long-term load capacity.
Thickness and strength answer different questions
Thickness is a dimension. Compressive strength describes material behaviour under a stated test. A thicker board is not automatically a higher-strength grade. Equally, a high short-term compression figure is not a permissible long-term floor loading: the designer must consider sustained deformation and the complete load path.
| Decision | Information to compare | Avoid this shortcut |
|---|---|---|
| Thermal insulation | Declared conductivity, thickness and test basis | Choosing solely by foam colour |
| Mechanical support | Grade, test conditions and long-term design data where required | Using a short-term kPa value as a floor load rating |
| Space coordination | Board thickness plus all other layers | Treating insulation thickness as finished-floor height |
| Exposure | Moisture, temperature and compatible adjacent materials | Assuming one board suits every environment |
Make thermal comparisons on the same basis
For a homogeneous layer, R = thickness in metres ÷ thermal conductivity. To work backwards, required thickness = target layer R × conductivity. The examples below assume 0.030 W/(m·K) only to show the arithmetic; they are not Banarta product ratings or whole-building U-values.
| Example thickness | Calculation | Layer R, m²K/W |
|---|---|---|
| 30 mm | 0.030 ÷ 0.030 | 1.00 |
| 50 mm | 0.050 ÷ 0.030 | 1.67 |
| 75 mm | 0.075 ÷ 0.030 | 2.50 |
If the insulation layer needs R = 2.00 at that assumed conductivity, the calculation gives 0.060 m, or 60 mm. If only 50 mm is available, the same material does not meet that layer target: revise the build-up or compare a documented lower-conductivity option. Do not replace thermal evidence with a higher compression number.
For loading, separate a short-term test from deformation under sustained load. A board described as 1000 kPa is not automatically approved for a floor pressure of 1000 kPa. Compare the grade and design evidence independently of the thickness calculation. See compression versus long-term creep and R-value and conductivity comparisons for the next step.
Specify the surface and fabrication
A smooth skin, a removed skin and a machined groove describe different supply requirements. Send a drawing if the board will be bonded, laminated or routed. Confirm tolerances and compatibility with the proposed facing or adhesive rather than expecting all XPS surfaces to behave identically.
Graphite-containing board is an option within the Graphite XPS Foam Insulation Board. Its material name should prompt a datasheet comparison, not an assumed percentage improvement. Published ranges may cover several configurations; ask which values apply to the quoted grade.
For an uncoated option, review the extruded polystyrene XPS foam board and its published dimensions and skin or grooved surface options. Compare the selected grade and finish with the requirements above before requesting a quotation.
A useful selection brief
- State the assembly and available height, not just “XPS board”.
- Provide the project thermal target and mechanical requirements separately.
- Specify dimensions, edge profile, finish and any machining drawing.
- Identify the documents required for the destination and intended use.
- Keep the agreed product reference and drawing revision with the quotation.
If two offers differ, first reconcile their specification and test basis. Price becomes meaningful only when both refer to the same deliverable.
Turn your selection brief into a supplier enquiry with the XPS insulation board RFQ checklist, covering board schedules, documents and delivery requirements.
Sources & product references
- Banarta graphite XPS product information
- JACKODUR technical data: separate short-term compression and creep properties; external reference, not Banarta certification
Product ranges are not a declaration for every configuration. Use current documents for the selected supply. External references explain general principles and do not certify Banarta products.
