Ysgol Gymraeg Y Trallwng

Welshpool, North Powys

The first Passivhaus hybrid project in the UK: a school merging a Grade II listed building with a new Passivhaus extension.

The existing building, which dates from late 19th century, has been repaired and refurbished to accommodate early years and community facilities. The extension housing classrooms and a new school hall has been built to Passivhaus standards to ensure a sustainable, low energy use building.


Education, Heritage




Powys County Council


Crookes Walker were responsible for supporting the MEP services contractor, MA Cooper Projects, with the detailed design development and contractor design portions including production of stage 5 coordinated working drawings, as well as as-fitted information and SBEM/EPC.

The merging of the Grade II listed building with the Passivhaus extension is the first of its kind in the UK and presented unique challenges for the design team. The project required careful attention when setting out the services to coordinate both with the heritage features of the building and the very specific requirements of Passivhaus.

The CWC team worked closely with the client architectural team to review the design and provide coordination of the building services to suit the specific needs of each building. This included detailed setting out of services openings in the buildings, with particular attention required for the Passivhaus extension, to allow the timber frame to be constructed off-site.

The project will help the Local Authority meet its ambition to reduce carbon emissions to net zero, whilst preserving a Grade II listed building in the community, and providing outstanding Welsh language based education.

Related projects