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Sans 10400-xa poses new challenges for the roofing industry The energy efficiency legislation for new buildings, SANS 10400-XA, has been published by the regulator (NRCS). All new buildings will have to comply with the performance parameters, which means that insulation will have to be installed to achieve the stipulated R-values. Words by Dion Marsh The new SANS 10400-XA legislation requires far deeper sections of uncompressed insulation in the roof cavity to achieve the new prescribed R-values. For insulation to perform effectively it needs to be installed in a continuous layer, without compression and with minimal thermal bridging. It is widely accepted that the ideal location for this insulation in the roof space is over the purlin. Over purlin installation avoids the obstructions imposed by trusses, bracing and reticulation systems which invariably would contribute to excessive thermal bridging. The challenge in the roofing industry is the interface between the outer roof covering and the underlying structure when accommodating these deeper depths of insulation. Until recently the roofing industry attempted to create roof cavities with various forms of steel U-spacers. These spacers were only partly successful, were labour-intensive, and still compromised the performance of the outer roof sheeting. The loose U-spacers did not support the longer fasteners which exceeded their design lengths, in turn increasing the risk of failure due to expansion and contraction of the outer roof covering. It is for this reason that most roll-formers of concealed fixed steel roof sheeting will not give a warranty on their product if installed over uncompressed insulation exceeding 50mm in depth.
yield galvanised bars of the ASHGRID SPACER SYSTEM by means of conventional self-drilling fasteners. The ASHGRID SPACER SYSTEM accommodates all forms of pierced and concealed fixed steel roof sheeting manufactured in South Africa.
Thermal and acoustic performance
Although the new SANS 10400-XA legislation only places emphasis on energy efficiency it is critical that roofs also perform well acoustically. There would be no point in having an energy-efficient roof on a school which amplified the drumming sound of rain and other external sources of noise. The ASHGRID SPACER SYSTEM allows the professional design team to combine configurations of rigid and cumulus insulation without compression to achieve a roof that is aesthetically pleasing while offering high thermal and acoustic performance.
The ashgrid spacer system has all the answers
It is critical that the interface between the roof system and the insulation should be considered during the design phase. The ASHGRID SPACER SYSTEM is designed to suit all SANS 10400-XA legislation building types and climate zones, including cyclonic regions. It raises the roof sheet above the purlin, creating a defined space for the insulation material to recover to its optimum design thickness and insulation value. The ASHGRID SPACER SYSTEM is an engineered system which transfers the loads of the outer roof covering evenly into the underlying roof structure. The outer roof covering is simply installed to the high
ashgrid Website: www.ashgrid.co.za
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