Built-up, insulated over roof system

This form of over-cladding is ideal for many refurbishment applications but it is important to recognise and address the need for including a Vapour Check or perhaps a breather paper to avoid the problem of interstitial condensation. Old buildings and the construction details they employed, were by their nature very ‘leaky’ with air and vapour movement not controlled. Over-cladding or over-sheeting will generally require the introduction of a vapour control layer (VC) above the internal sheet and below the insulation.

The refurbishment of roofs with existing roof-lights can be a problem, and generally the client would have to accept a reduced level of light through the roof-light as a result of the introduction of a VC. Cutting and sealing the VC around every rooflight could overcome this but can add considerably to the overall cost.

Solution

• Suitable for over-roof cladding failing pitched roofs of any material. The new roof provides long, trouble-free life.
• Retains the old roof cladding for use as a liner.
• Causes minimal disruption inside the building.
• Uses support brackets attached over the old sheeting into the purlins to provide an insulation space with minimal cold-bridging. New insulation is added to reduce heat loss and maintain internal temperature according to current building regulations. Finally, the external top sheet is installed.
• Provides the option for a new vapour protection layer to be added if the old roof cannot be adequately sealed. This is to keep internal moisture out of the roof void and prevent air leakage in line with current building regulations.
• Allows for the existing roof covering to be removed and replaced with a metal lining panel in combination with improved insulation and a new metal top sheet.
• Can be used for wall cladding. The illustration shows a new wall cladding system, which completely revitalises the building appearance. In this case, the previous old single skin sheeting has been removed.