BUILDING CONSTRUCTION Element Type
Pitched roof – insulated at ceiling level Pitched roof – insulated at rafter level Flat roof or roof with integral insulation Walls – Cavity insulation
Walls - internal or external insulation Floors
Improved U-values – Non-Domestic
0.16 0.18 0.18 0.55 0.30 0.25
Table 3 (above): Improved U-values for existing elements under ADL2 2021 in England. It is expected that Welsh requirements will be at least similar to these.
Right: Vacuum insulation panels can provide a problem-solving solution in applications where space is at an absolute premium.
uncommon to come across areas where the available depth for insulation is highly limited. Typical examples include when attempting to insulate above an existing solid floor. If the insulation is too thick it can reduce the floor to ceiling height, and also mean that fixtures and fittings need to be raised. Similarly, where existing flat roofs are converted into roof terraces, it can be challenging to ensure that the roof is well insulated while retaining an even transition between the internal and external spaces. In these applications, vacuum insulation panel (VIP) systems can provide a solution. VIPs feature a microporous core which is evacuated of air and sealed in a gas-tight envelope. This allows the panels to achieve an insulating performance up to five times better than some commonly used insulation materials. As the VIPs themselves cannot be cut,
they’re typically provided in a range of dimensions, and installed in systems along with rigid insulation boards of the same thickness, which can be cut to size to allow for penetrations, and to fill awkward gaps between the VIPs or around the perimeter. VIPs systems are available for both floor and flat roof applications. Additionally, systems are now available which encapsulate the VIP in a protective spray layer, providing a robust solution for inverted roof applications.
Ponding water Another common problem area for healthcare estates is where water is ponding on flat roofs. This can be caused by a variety of issues, including blocked drains, debris on the roof, or an insufficient drainage fall in the roof itself. Where this issue reoccurs frequently, it may be necessary to re-establish the fall. In this application, tapered roofing systems can provide a simple solution. These systems combine standard flat insulation boards with tapered and hip and valley boards which can be used to provide the drainage fall. They’re typically supported with design services, creating a clear system layout to achieve the desired thermal and
84 Health Estate Journal October 2022
drainage requirements. The lightweight boards add minimal structural loading to the deck, can be fitted with a dry installation process, and – depending on the condition of the roof – in some cases can be fitted without having to strip the existing waterproofing layer.
Retrofit framework Ultimately, refurbishment projects are more complex than new-builds, and there is no one-size-fits-all solution. For this reason, it is important that the improvement work is carefully tailored to the individual building. To support this, a Retrofit Framework has been created, underpinned by two publicly available standards: n PAS 2038:2021 – which covers the assessment of existing buildings, development of an improvement plan and specification, and evaluation of the energy efficiency measures once installed.
n PAS 2030:2019+A1:2022 – which covers the installation and commissioning of these measures. The Retrofit Framework sets out a clear process for each building to be risk assessed, and for a retrofit strategy to be developed. This not only identifies what remedial work is needed, and which energy efficiency measures are appropriate, but also sets out a clear order for them to be installed in to deliver best value. It also provides extensive guidance on how measures should be handed over and evaluated post-installation to ensure that they are performing effectively. This ‘whole building approach’ can help estate teams to plan a clear and logical improvement plan for all buildings, ensuring good value and lasting reductions in emissions and energy demand.
Setting a clear path As we move toward a zero-carbon future, it is important for specifiers and Estates teams to have a clear understanding not only of all of the updated regulatory requirements, but also the path ahead. By aiming for high standards of fabric
performance in new projects, and raising the performance of existing buildings where feasible, it should be possible to limit the operational demand and cost of buildings, and raise them to full net zero performance in the future with minimal cost and disruption.
References 1 Climate Change Committee. The Sixth Carbon Budget [Internet]. 2020 [cited 01 July 2022].
https://tinyurl.com/2p8wvjba
2 NHS England. Delivering a ‘Net Zero’ National Health Service [Internet]. 2020 [cited 01 July 2022].
https://tinyurl.com/ yc53v4m5
Jonathan Ducker
Jonathan Ducker is head of Regulatory Affairs at Kingspan Insulation GB. With an extensive understanding of the technical and policy issues surrounding energy efficiency, sustainability, and low and zero carbon technologies, he is regularly involved with construction industry working groups for building regulations and standards relating to new build energy efficiency, net zero, moisture in buildings, and retrofit. He has represented trade associations for English, Welsh, and Scottish building standards, and has contributed to a variety of articles and publications.
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