Passivhaus Early Childhood Centre

The Dunlop Early Childhood Centre for East Ayrshire Council is targeting Passivhaus, following a switch to the design brief at RIBA Stage 3. The project is being designed by an in-council team to develop Passivhaus capabilities in-house.

Dunlop Early Childhood Centre. Image credit: East Ayrshire Council 1

'The Bridge', Dunlop Early Childhood Centre is a new build nursery situated in the rural village of Dunlop, East Ayrshire and will accommodate 72 children and 14 staff. The project is aiming to be East Ayrshire Council's first Passivhaus new build and has also been used as a Pathfinder project to help develop the Net Zero Waste Standard. The building consists of a single storey and a central double height playroom with a mezzanine level ‘the bridge’.

Passivhaus was retrospectively applied to this project at RIBA Stage 3 by the Council, which also decided to train its own team as in-house Passivhaus Consultants to deliver the project and build Passivhaus design capacity. The Council team were supported by experienced Passivhaus practitioners Collective Architecture who acted as Passivhaus Site Compliance Officer.

Key stats

Construction: Timber kit frame with extended Lasson truss detailing and Glulam portal frame

TFA: 320.84 m2

Build start date: 2022

Completion: Aiming for 2023

Certified: Aiming for Passivhaus Classic

Dunlop Early Childhood Centre. Image credit: East Ayrshire Council

Our in-house consultants underwent a massive learning curve of intense training and knowledge sharing to bring the project on track for Passivhaus certification. We are really proud of our team of in-house consultants, external consultants and contractor for their progressive approach and commitment to deliver what we hope is East Ayrshire Council's first certified Passivhaus building.

Siobhan McGale Project Manager /Senior Architect, East Ayrshire Council

The project is located on a previously inaccessible and abandoned brownfield site. The design to the north of the site includes a curving balcony which exploits the rural farmland views and the natural sounds of Gills burn. Deep window reveals and an external free-standing canopy have been employed as the summer comfort strategy. A detailed assessment of internal equipment load profiles was undertaken to minimise the risk of overheating from kitchen areas.

Dunlop Early Childhood Centre. Image credit: East Ayrshire Council

Construction

The building is being constructed with timber kit frame with extended Lasson truss detailing and Glulam portal frame. An expanded polystyrene insulation (Stylite EPS) system has been specified for the ground floor.

Due to Passivhaus being retrospectively applied to the design, the building had a high form factor which the team felt was always ‘working against them’ through the construction detailing phase. This resulted in the need for thicker walls (Timber kit / Larson truss detailing) and the architects having to work closely with the structural engineers to meet the PHPP targets and Passivhaus criteria.This process reinforced the importance of considering Passivhaus very early on in the design stage, and the fact that the better the form factor, the less complex the construction, fewer materials required and more cost-effective the building is. The in-house team will be taking these lessons learned into the next project ensuring form factor benchmarking is incorporated at the early stages of the design.

Training sessions undertaken by East Ayrshire Council have helped promote the education of specialist trades to ensure everyone understands the level of quality assurance required. Passivhaus airtightness training inductions have been carried out for trades working on the project, including presentations and tours of the building, highlighting important details on-site, to increase their understanding and awareness of the airtightness details and sequencing.

Dunlop Early Childhood Centre - The collaboration and quality assurance needed onsite is unprecedented and intense but one of the most exciting things about building a Passivhaus. It drives forward a new wave of collaborative working and problem solving between designers and builders to ensure a quality build.. Siobhan McGale Project Manager /Senior Architect, East Ayrshire Council

Embodied carbon

Construction embodied carbon and circularity was considered during material selection. At the project stage there were limitations in terms of possible changes to previous material specifications, but options were investigated by the project team. Further suggestions on the specification of the substructural elements (with the potential of 40% saving on embodied carbon) and guidance was provided for contractor documentation on best practice waste minimisation.

Overall U-values

Floor: 0.1 W/m2K

EPS insulation

Dunlop Early Childhood Centre on site. Image credit: East Ayrshire Council

Wall: 0.069 W/m2K

Mineral wool insulation with insulated wood fibre joists.

Roof:

Flat roof: 0.069 W/m2K

PIR insulation board

Pitched roof: 0.075 W/m2K

Mineral wool insulation with insulated wood fibre joists.

Building services

The project utilises two MVHR systems as the primary ventilation strategy for the building but the windows still open inwards to allow for natural ventilation if end-users feel they required this. To accommodate the MVHR ductwork, the ceilings needed to be lowered to accommodate the 400 mm service zones. The lower ceilings were not in the original design but was one of the design adjustments required when Passivhaus was added as a requirement at RIBA Stage 3, resulting in the building having a somewhat domestic scale feel to it.

The project has specified an air source heat pump (ASHP) in lieu of traditional gas boilers. The building utilises a hybrid design of a central water heater with the addition of at point of use heaters at locations further away from the central plant room.

Key team

Architect: East Ayrshire Council

Passivhaus Consultant: East Ayrshire Council

Passivhaus Site Compliance Officer:

Collective Architects

Contractor: Ashleigh (Scotland) Limited

Structural engineer: Kiloh Associates

Landscape Architect: ERZ Landscape Architects

M&E consultant: East Ayrshire Council

Clerk of Works: Ross Quality

Passivhaus Certifier: WARM

https://www.passivhaustrust.org.uk/news/detail/?nId=1235

6th March 2024