Roof Terraces: Insulation panels for use beneath waterproofing systems for roof terraces
The technique of insulating roof terraces using insulation panels beneath waterproofing systems is commonly used for the thermal insulation of flat or pitched roof terraces for new-build and refurbishment projects. This technique is described in the DTU série 43 French building regulations for use in upland and lowland sites. The guide UEAtc – Cahier du CSTB 2662_V2 of July 2010 sets out the criteria and minimum suitability requirements to be complied with, depending on the accessibility and planned use of these roofs and the materials used to create the insulating layer.
Most roof terraces insulated with insulation panels installed beneath a waterproofing system are made up of the following four elements:
- a load-bearing element (concrete, masonry, ribed steel sheet, wood and wood-based panels, etc.)
- a waterproofing system base (insulating panel with or without vapor barrier)
- a waterproof membrane (single or twin layer bitumen, synthetic membrane, liquid waterproofing system, etc.)
- a waterproof protection layer (fine gravel, slabs on studs, prefabricated concrete slabs, planted roof system, etc.)
Insulation products used in roof terraces are subject to a very varied range of thermal, hydric and mechanical stresses (fluctuations in external temperature, relative humidity, storms, compression loadings, wind-generated pressure drops imposing traction forces within the insulation material, etc.).
ACERMI certification provides proof that the insulating product used complies fully with thermal conductivity (λ) and thermal resistance (R-value) requirements. It can also certify more specific characteristics depending on the particular type of roof for which the insulation material is intended. In this way, key characteristics, such as dimensional stability, compressive strength at 10% deformation, resistance to traction perpendicular to the surfaces, sheer strength and water absorption, are all certified by ACERMI.
As part of ACERMI certification, the manufacturer benefits from production inspections conducted at least twice every year by an independent body to check that the quality of the insulation product is consistent and meets the requirements of its certification.
Once the insulation product has been correctly selected, all that remains is to follow the recommendations in the Technical Assessment or Technical Application Document to achieve long-term high insulation performance.