TEP ROOF OY · PROJECT PLANNING GUIDE
Thermal insulation options
Mineral wool, PIR, EPS and expanded clay serve different roof build-ups. Compare the whole roof assembly, rather than insulation board prices alone.
Key considerations for each option
- Mineral wool: load-resistant board and lamella systems are available for low-slope roofs. Check the product-specific reaction-to-fire class and the load resistance of the insulation combination in the documentation.
- PIR: low thermal conductivity allows a thinner insulation layer. Select the facing, waterproofing substrate and fire protection as part of an approved roof build-up.
- Expanded clay: suitable for shaping the roof and forming falls. Additional insulation may include EPS or mineral wool, for example. The build-up needs designed ventilation and space for its layers.
Compare on the same basis
- Request options with the same thermal performance target. Check the build-up height, self-weight, moisture management, and loads from maintenance and roof equipment.
- EPS products have different uses and strengths. An EPS 60S designation in an individual construction detail, for example, cannot be applied as the insulation specification for every roof.
If the insulation has not been decided
- Leave the selection open and provide details of the load-bearing structure, available height, and the project fire and loading requirements. The designer identifies suitable complete build-ups for comparison.
Use and design responsibility
TEP Roof Oy guide cards support project preparation and the definition of contract scope. They are not project-specific construction designs. The project structural designer is always responsible for checking the suitability of the solutions presented and adapting them to the project's structures, loads and requirements. Construction requires project-specific design and approval, together with the current manufacturer's instructions for the selected products.
Sources
An editorial compilation by TEP Roof Oy. The product- and system-specific source instructions must be checked for the selected solution.
- Saint-Gobain Finland Oy / ISOVER: Low-slope roofs: system guide 07/2026 Checked 12.10.2026
- Finnfoam Oy: FF-PIR thermal insulation boards: technical data, 1 January 2026 Checked 12.10.2026
- Leca Finland Oy: Leca expanded clay roof with additional insulation Checked 12.10.2026