Case Study: Prototype Two-Bedroom Bungalow
At Ty Eco MMC, our decision to manufacture Timber Frame – and specifically, Timber Frame for building Passive Houses – we realised the best way to learn was by doing. As part of our 5-year R&D program, we embarked on building a prototype two-bedroom bungalow in Minera, aiming to meet Passive House standards or come as close as possible across key metrics. The project also had an additional goal: to design a building system suitable for future social housing that could help combat fuel poverty in the UK.
Client
Prototype Two-Bedroom Bungalow
Location
Vicarage Hill, Minera
Project Brief
In communication with Wrexham Council, we designed the bungalow to not only meet the Welsh Future Homes standard and DQR (Design Quality Requirements) but also to surpass Welsh Building Regulations. This approach would ensure that our system could be applied to public sector housing and help reduce energy consumption and costs.
Step 1: Foundation and Wall Panel Design
We began the project using the Isoquick system to form a raft foundation, which provided an insulated and thermally efficient base for the building. For the superstructure, we developed our first prototype panel using a 250mm box truss for the wall studs (this has since been replaced with a 300mm I Joist in our final panel design).
Wall Panel Specifications:
Internal Sheathing: Medite Smartply Propassiv, which provided the airtightness needed for Passive House standards.
External Sheathing: 18mm Kronospan OSB3 for racking strength and stability with Partel’s Mono 150 breather membrane
External Insulation: 120mm Rockwool battens, mechanically fixed to the OSB, for extra insulation and a solid base for external finishes.
External Finish: A silicone-based render system applied over a flexible mesh system, ensuring a robust and weather-tight exterior.
Step 2: Roof Design and Adaptation
While our initial design aimed for a flat roof, which would have simplified meeting Passive House standards, planning permission required a pitched roof. To accommodate this, we added a trussed roof on top of the flat roof insulated panels. Although this was not the most cost-effective solution, it fulfilled both our R&D objectives and planning requirements.
The roof was sarked with OSB and covered with a roofing ‘felt’ membrane, followed by a slate-lookalike product made from recycled rubber tyres—a sustainable and visually appealing choice, as seen on Grand Designs.
Step 3: Installation and Airtightness
The wall and roof panels were installed within 5 working days, with all joints carefully taped to ensure airtightness. Windows and doors were fitted during this time, and by the end of the installation, we had achieved airtightness of 0.34 ach, exceeding expectations for a project of this size.
Our U-value target for the building was 0.1 W/m²K, which was also met, making the bungalow highly energy-efficient. While we narrowly missed full Passive House accreditation, primarily due to the difficulty of achieving the standard with small bungalows (due to the form factor), we achieved classification as a 'Low Energy Building' according to the Passivhaus Institut metric.
Key Performance Metrics:
Airtightness: 0.34 ach (air changes per hour)
U-Value: 0.1 W/m²K
Passive House Performance: Classified as a 'Low Energy Building' by PHPP
Step 4: Monitoring and Occupant Feedback
After completion, the bungalow was rented to a couple, with the understanding that we could occasionally monitor the building’s performance. Over the past three years, the results have been outstanding. Heating bills are minimal, the air quality remains excellent due to the MVHR system, and the bungalow is almost completely soundproofed—a surprising benefit of the Passive House approach.
The building is off-grid for gas, with all heating provided by an electric Air Source Heat Pump, complemented by the heat recovery from the Mechanical Ventilation with Heat Recovery (MVHR) system. This combination has created a comfortable, low-energy living environment, constantly maintained at between 20-21°C.
Conclusion
The Prototype Two-Bedroom Bungalow in Vicarage Hill, Minera demonstrates Ty Eco MMC’s commitment to pushing the boundaries of sustainable construction. While the project did not achieve full Passive House accreditation, it met or exceeded key performance metrics, providing a highly energy-efficient and airtight home. The success of this prototype shows great potential for addressing fuel poverty and providing sustainable housing solutions for the future.
The biggest success from the project was what we have learned and since applied to our final panel designs for our signature product, the Adra PØ Passive Panelised Timber Frame Building System.
