Built-up metal roofs

Profiled metal roofing systems typically consist of a low profile metal inner liner sheet, separated from an outer, higher profile, metal weather sheet. The cavity between them is filled with a layer of thermal insulation to provide the specified level of thermal performance.

Design considerations

The designer will have to consider many things when designing a building with a built-up metal roof. The following both influence and are influenced by the insulation materials in the system:

• Thermal insulation

• Air permeability

• Thermal bridging

• Acoustic performance

• Fire safety

• Control of condensation

• Environmental impact of the materials


The insulation is normally a lightweight, high performance, non-combustible glass mineral wool quilt, with a Euroclass A1 fire rating. Built-up metal roofing systems are typically assembled on site with the design and components used forming part of a proprietary system.

Incorporating glass and rock mineral wool insulation within a built-up metal roof system is one of the most cost effective methods of improving its sound insulation performance. When the effects of separation and sound absorption are combined in a built-up metal roof it is possible to achieve outstanding levels of sound insulation.

It is a requirement of the Building Regulations that external cladding elements shall resist the spread of fire from one building to another. Glass and rock mineral wool are non-combustible with a Euroclass A1 `Reaction to fire` classification.


Download the Built-up metal roofs application PDF