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Kingspan insulated roof and wall systems are manufactured with factory applied anti-condensation/vapour control tape for use in humidity classes 1 to 4 (in grey). Parts L2 and J approved construction details are also suitable for application within the same humidity classes.
Advice should be obtained from Kingspan Technical Design Bureau about additional measures for humidity classes (in terracotta) which may only involve the fitting of a site applied vapour control sealant along the panels at the liner joints at the time of installation.
Designers of chill and coldstores should consider the reverse condensation effect where the external temperature will normally be higher than the cold low moisture content internal air resulting in moisture migration into the building. In these circumstances the effective vapour sealant has to be located towards the external skin of the panels.
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Interstitial Condensation Risk
The improved insulation values for Parts L2 and J of the building regulations have increased the risk of condensation within built-up cladding because of the lower temperatures created at interstitial surfaces.
BRE Report: 262 Thermal Insulation:
Avoiding Risks was updated to the third edition to comply with Building Regulations Parts L2 & J:
2002, this document states: 2.12 Pitched roofs of profiled sheet - risks and avoiding actions - condensation within the construction
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- Use a composite roof where possible and ensure that:
- extract ventilation is provided close to processes producing water vapour
- all voids are filled with foamed plastic insulation
- all joints incorporate an effective vapour seal to prevent moist air reaching the cold overlapping metal sheet
Along with BS5250: 2002 Code of Practice for Control of Condensation in Building, BS6299 Flat Roofs with Continuously Supported Coverings has been amended to refer to standard values of thermal conductivity and vapour resistance given in CIBSE Guide A3 and BS EN 12524. This document is also applicable for low pitch metal roof systems.
Humidity, condensation risk and thermal performance are key design and performance issues - Kingspan Technical Design Bureau expertise is available to provide project specific building physics input and solutions.
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Thermal Insulation Failure Risk Factors
Lower U-values and insulation continuity required by Parts L2 and J demand certainty of insulation performance over the building’s lifetime and the removal of any risk within the building fabric of increased thermal conductivity, whatever the cause. The major risk factor is the potential for build up of moisture or vapour causing interstitial condensation within the insulant which results in physical degradation leading to thermal performance failure.
Thermal Failure & Increased Operating Costs
Examples of thermal failure due to lack of insulation continuity, cold bridges and insulation defects (impact of 3% missing insulation due to gaps reduces U-values by the following:
roofs – 0.25 to 0.33W/m2K
walls – 0.35 to 0.43W/m2K
*Conversion of energy to Carbon emissions based on an average fuel efficiency.
Installation Quality Risks
Man-made mineral fibre materials are vulnerable to poor installation leaving gaps or physical deterioration (compression)
Kingspan Closed Cell Insulated Roof and Wall Systems
Installation Quality Certainty
Factory, pre-engineered systems facilitate superior quality site installation
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Insulated Panels Systems
Kingspan insulated roof and wall systems utilise closed cell insulation between impervious metal facings which prevents any moisture or vapour ingress into the insulation core, thus ensuring long term thermal (U-value) reliability and insulation continuity. Factory pre-engineered quality guarantees reliability of thermal (U-values) and insulation continuity.
Site Assembled Built-up Machine-Made Mineral Fibre Systems
Machine-made mineral fibre insulants have performance issues relating to their open structure - they are moisture, vapour and air permeable. This can result in build up of interstitial condensation, dampness, wetting causing large increases in thermal conductivity. The open fibre structure means that air movement over and through the insulant will additionally reduce its thermal performance.
Other risk factors include settlement, ageing and compression of the insulant and missing insulation caused by workmanship defects, these combined with interstitial condensation, dampness, wetting have a catastrophic impact on thermal performance.
Challenges to Insulation Performance
Machine-Made Mineral Fibre Insulation
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