STRATHERM® is a roof underlayment HPV (High Permeability to water Vapour) with thermal insulation reinforcement. It is a roof underlayment and radiant heat shielding.


STRATHERM® can be laid, either directly on insulation, either onto discontinuous support with a non- ventilated air space, underneath. Its intrinsic thermal performances combined with its metallic faces, will increase the buildings thermal insulation and improve summer comfort.


  • STRATHERM® is laid in compliance with standards and DTU in force as well as installation rules for certified flexible roof underlayments (CSTB notes N° 3651- 2 of January 2009).
  • STRATHERM® is unrolled, parallel to the gutter line with 10 cm overlapping, by using the upper tongue for slope > 30%. If slope is ≤ 30%, it's necessary to make a suitable sealant bead under the upper tongue.
  • STRATHERM® is a symmetrical product to optimise cuts, waste as well as installation time. For example, an oblique cut used for valley can be reused above, simply flip the product.
  • STRATHERM® is easily cut with a utility knife (for more safety, use a snap- off knife).


  • Traditional laying, stretched on rafters or roof trusses with nonventilated air space underneath: jointing between STRATHERM® and edge or gutter supports is made with a sealant bead to ensure a non-ventilated air space under the screen.
  • Direct laying onto insulation: the water vapour permeability (HPV) of STRATHERM® allows to be laid directly on insulation.


- Roll dimensions: 16 m x 1.6 m (1.5 overall) / 24 m²
- Roll weight: about 14 kg

Regulations and approvals

STRATHERM® is used as indicated in DTU 40.1 and 40.2 to protect roofs with discontinuous supports (stretched laying on rafters or roof trusses with 90 cm maximal centres) against penetration risks of powdery snow, dust, soot or pollen. The 1999 storm showed how useful is a roof underlayment to limit back pressure effect and by the same, tiles grubbing up. STRATHERM® helps temporary the building to be kept weathertight but must not exceed 8 days. In compliance with DTU guidelines, STRATHERM® eases access to minimal slope of covering lower. Its high permeability to water vapour avoids condensation on the underside and protects elements of the bearing structure. STRATHERM® is appropriate as rainscreen, in compliance with standards NF P 21- 204- 1 (Ref DTU 31.2 - “Timber frame houses and buildings”) and NF P 65- 210- 1 (Ref DTU 41.2 – “Exterior wooden cladding”).