Overview of New Build Built Up Metal Roof & Cladding Systems

MRC Groups new build built up metal roof systems comprise of an internal steel walkable profiled liner sheet and an external concealed fix or pierced fix external roof sheet separated by the patented AshGrid™ spacer system forming a structural cavity.

The internal walkable liner sheet is installed onto the top flange of the purlins providing top flange restraint and protection against wind uplift to the external roof sheeting. This liner sheet provides a clean soffit to the inside of the building and a safe platform to install the remaining roof system.

The patented AshGrid™ System is installed in the troughs of the steel profiled walkable liner sheeting with the brackets fixed directly to the underlying steel or timber purlins, thus creating an engineered, structurally defined cavity between the two new roof coverings. When insulated this cavity provides excellent thermal capabilities up to 10 R-Values & Acoustic Sound Reduction over 40dB as a standard.

MRC Groups installed built up metal roof & cladding systems are backed with the unrivalled single source Guardian™ System Warranty which covers materials, installation & maintenance for the term of the built up metal roofing and cladding system.

Key Features of Built Up Metal Roofing & Cladding Systems

  • Full range of aluminium and steel ‘Secret’ & Pierce Fix roof and cladding systems
  • R-Value thermal performance up to 10 (m2.K/W)
  • Acoustic sound reduction of 40dB as a standard – additional layers can be added to increase to over 58dB
  • Installation of the walkable steel liner sheet over purlin provides a safer working platform
  • Installation of the liner removes the rest of the roof off  the critical path, while internal works can continue under the protected area
  • The liner sheet can be sealed to form an air-tight barrier to provide an even more energy efficient roof & cladding system, ensuring that cool or warm air stays within the building space
  • Range of bracket heights up to 350mm provides tailored performance for your project
  • LPCB non-combustible rock and glass mineral wool used in built-up metal roofs have the advantage of offering high levels of fire resistance and potentially lower insurance premiums
  • Backed with the up to 20 year ‘Guardian’ System Warranty

Applications of Built Up Metal Roof & Cladding Systems

Built up metal roof or double skin systems have been used throughout the world for over 20 years providing energy efficient roofing & cladding solutions for new build property.

With the new south african government standards, SANS 10400 XA legislation, the search for energy efficient metal roofing & cladding systems has certainly begun. MRC Group has been designing, installing and maintaining such built up metal roof systems for over 10 years providing our clients in Africa real experience to ensure excellence.

  • Industrial applications such as Workshops, Factories, Food Processing Facilities and Automobile Assembly Property that require to keep the the noise within the building.
  • Commercial and Retail space such as Shopping Malls and Offices that are looking to reduce their increasing energy costs with a high performing thermally efficient roofing & cladding system.
  • Governmental, Educational, Prison & Transportation Property such as Airports, Schools, Universities, Train Stations and High Security Property that requires both acoustic and thermal performance.

Technical Data of Built Up Metal Roof & Cladding Systems


ASHGRID™ Metal Spacer Support System for Built Up Metal Roof & Cladding Systems

  • Brackets with thermal pads – standard height range from 60 – 300mm (Deeper brackets available on request)
  • Standard Bar lengths from 1.2 / 2.4 / 3.6 Metres
  • 2 No. Self-Driller Fixings per Bracket – AshFix Mild Steel 5/16 Hexagonal Head LS25 (Steel Purlins) or TF45 (Timber Battens) Self Driller Fixings, with an integrated 16mm washer flange, fixed through the liner sheet into the structure

Thermal Insulation for Built Up Metal Roof Systems

  • Full range of insulation types & thicknesses available
  • Fire Classification Class 1 (non-combustible)

Please note that insulation compressed between purlins & roof sheets will lose at least 35% of the proclaimed R-Value, a constant cavity thickness does NOT compromise the R-Value. Built up metal roof & cladding systems provide significant advantages over traditionally constructed systems.

The table below provides the R-Values that can be achieved using a built up metal roof system.

Acoustic Data – Sound Reduction

  • 0.55mm Steel Roof System 40dB +
  • 0.8mm Aluminium Roof System 42dB +
  • 0.8mm Steel Roof System 48dB +

Weight of a Typical Built Up Metal Roof System based on purlins at 1800mm centres

  • 2 No. 135mm Bracket per Ln Metre                        1.0 kg / m2
  • 135mm roll out insulation                                   1.7 kg / m2
  • 55mm Secret Fix / Pierced Fix Roof                     6.0 kg / m2

                                                          Total Weight  8.7 kg / m2

Alternative Built Up Metal Roof Sheet Options to Consider

  • 0.8mm Aluminum Roof System                             4.0 kg / m2
  • 0.8mm Steel Roof System                                   9.0 kg / m2

Built Up Metal Roof System Warranty

  • Up to 20 year, single source ‘Guardian’ System Warranty covers Design, Materials, Workmanship & Maintenance

Guarantees & Warranties of an Built Up Metal Roof & Cladding System

MRC Groups up to 20 year ‘Guardian’ System Warranty cuts through the myth & mystic of product guarantees and workmanship warranties issued by the construction industry.

Traditionally a product guarantee would be issued by the manufacturer and the workmanship warranty would be issued by the installer of the over-roofing system. Two separate pieces of paper, with differing length of terms and when put alongside each other, never answered the question of who will pay for the materials and works such the over-roofing system fail.

‘Guardian’ System Warranty is an unrivalled new era of warranty that covers Design, Materials, Workmanship & Maintenance. The length of term for each element matches and is issued as a single source, transferrable warranty for the life of the guarantee of the built up metal roof system.

MRC Group challenges the construction industry to ensure that the workmanship warranty issued by contractors matches the length of term of the supplied built up metal roof & cladding system, thereby ensuring high quality installations with designed and tested built up metal roof & cladding systems.