Passivhaus Plus plans progress at Kew
The proposed Passivhaus Plus Learning Centre, being developed for the Royal Botanical Gardens at Kew, is moving a step closer, following changes to the initial designs.
A revised design has been developed, following feedback from planning department and Historic England on the initial designs. The visual impact of the building on the gardens has been reduced by limiting the two-storey parts of the development to the far side of the site, with the roof pitched at a shallow 9 degrees and clad with sedum to the lower level and PV cells to the higher area.
The project team is now in the process of drawing up stage 2 designs, leading up to the submission of a pre-application to the local planning department.
Space to learn
The new Learning Centre will replace a redundant building, which is not suitable for refurbishment or adaptive reuse. The Centre aims to be an inspirational space for users of all ages, appeal to a broader range of audience, and be more flexible than the current space.
The space comprises
- Learning spaces (x 6)
- Toilets (public & staff)
- Open plan office
- Individual office
- Meeting rooms (x 2)
- Welfare & kitchen
Aiming for Passivhaus Plus
The proposed learning centre aims to be built to zero carbon standards, both in material construction and ‘in-use’ performance. A central element of the client brief was for the building to be certified Passivhaus and early modelling of the design has confirmed that this will be achieved, even potentially achieving the Passivhaus Plus level.
Heating and energy sytems currently being considered include air source heat pumps and solar photovoltaic cells
The Centre aims to generate sufficient renewable energy using solar photovoltaic panels to offset the embodied carbon of the building materials. A building carbon assessment is underway and will inform the number of renewables required for the site to pay back the embodied carbon of the structure.
Protecting tree roots
In order to prevent damage to the surrounding tree root network, the building footprint has been limited to the footprint of the previous building and only extends beyond this point where the root protection zones cease. The proposed building will be built from the slab level of the existing building, using the slab as the substrate for the insulated raft of the new building. This both prevents any impact on the tree root network and also provides an excellent thermal bridge-free foundation detail.
Plant-based
Materials that sequester carbon and are sourced locally to Kew are the design team's preferred materials, with timber, both for cladding and structural components, being a plentiful option. External walls will be clad in a mixture of timber cladding and K-briq outer skin cladding, which are formed from 90% recycled content. The timber species to be used on the clad elements of the facade will be from Kew’s stock and are likely to be multiple timber species to illustrate the variety of cladding types and textures available to the UK.
The design team is also considering using an insulation material derived from mycelium, which uses the root structure of mushrooms, combined with locally sourced waste to form panels of insulation which perform as well as conventional synthetic alternatives. An array of angled algae panels which generate energy when heated by the sun, might form part of an educational display on the building exterior. The energy created will then be displayed, along with meteorological data to show the effect of varying levels of sunlight. Installing green sedum roofs aims to support a net increase in biodiversity for the building.
Key teamClient: Royal Botanic Gardens Kew Architect: Hazle McCormack Young LLP Passivhaus & M&E consultants: QODA Consulting Structural Engineer: Pick Everard Planning consultant: LUC Passivhaus Certifier: MEAD Consulting |
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James Galpin, Architect & Principal Designer at Hazle McCormack Young (HMY), will be speaking about the Kew Gardens Learning Centre at the UK Passivhaus conference on 26 October 2022. Join us online or in person in Exeter.
Further information
Kew Gardens Passivhaus Learning Centre
Passivhaus for Educational Buildings
Passivhaus Schools & Educational Buildings
Previous PHT story: A Botanical Passivhaus - 7 February 2022
3rd November 2022
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