Technical Perimeter Detail Checklists

Summary sheet of the correct construction of Perimeter Details for specification or tender analysis all backed with the ‘Guardian’ System Warranty


Our summary sheets for the correct specification and construction of metal perimeter details are all backed with the ‘Guardian’ System Warranty, providing cover for design, materials, workmanship & maintenance for ‘up to 20 years.’

We are delighted to provide a library of these summary sheets to be used in conjunction with our specifications, technical data sheets and technical drawings at either specification stage, tender analysis or as a checklist on-site to ensure high quality installations.

Insulated Metal Roofing Systems

Please note that the use of compressed insulation fixed between purlin and the roof system will reduce the thermal performance of the insulation by up to 40% from the stated uncompressed R-Value.

If bulk density insulation over 75mm is used in conjunction with a ‘secret fix’ roof system then unclipping of the roof sheet can occur over time due to the pressure from the compressed insulation on the underside of the roof sheet.

Built Up Metal Roof Systems

Please note that the use of a metal built up roof system provides the most structurally stable and thermal proficient roofing system, as the insulation is not compressed and therefore much higher R-Values can be achieved with no added pressure on the roof system.

The structural cavity created by the AshGrid bar & bracket support system is structural stable with brackets from 60mm to 300mm high, fixed through the walkable trapezoidal liner sheet into the purlins. This method of construction is extremely safe to install, as the liner sheet provides a safe platform to install the rest of the roof system and also provides lateral restraint to the top flange of the purlins.

Over-Roofing Systems for existing Asbestos or Metal Roofs

This method of refurbishing an existing roof or cladding on a building is ideal, as the existing roof system remains in place reducing stripping & disposing costs and allowing the works to be completed whilst operations within the building continue.

Over-Roofing systems provide the opportunity to upgrade the thermal and acoustic performance of the existing roof and cladding system reducing the costs for cooling or heating your building.

Please feel free to contact us should you wish to discuss all these options on projects you may be considering.