Supporting Redrow Homes with Part O Overheating Compliance for their De Clare Gardens development in Caerphilly
We worked closely with Redrow Homes, a leading Welsh housebuilder, to support their De Clare Gardens development in Caerphilly with comprehensive Part O overheating assessments. The site includes 260 dwellings of varying house types, including non-standard designs that posed particular challenges for compliance.
The Challenge: Part O Compliance
The De Clare Gardens development required overheating calculations to demonstrate compliance with Part O of the Building Regulations. This regulation ensures new dwellings are designed to avoid internal temperatures that negatively affect occupant comfort and health, particularly during heatwaves. Learn more here.
The challenge was twofold:
- To deliver full compliance with Part O for all 260 dwellings, including bespoke G series house types with complex glazing and ventilation arrangements.
- To do so without compromising Redrow’s architectural and design intent.
Our Solution: Dynamic Thermal Modelling
While overheating risk is typically assessed using simplified methods, more complex house types such as those on this site required detailed dynamic thermal modelling following the TM59 methodology for the assessment of overheating risk in homes. Our sustainability consultants delivered this comprehensive modelling for the entire development.
This was a substantial technical exercise involving:
- Gathering detailed input data on glazing, ventilation, fabric, and occupancy assumptions.
- Collaborating closely with Redrow’s technical team to understand design parameters and constraints.
- Interpreting results expertly to identify potential overheating risks and develop practical mitigation strategies.
Our consultants provided clear, actionable guidance, ensuring regulatory demands were met while maintaining the integrity of the original design.
Dynamic Thermal modeling provides a powerful tool to ensure that the homes we built today are not only energy efficient but are also prepared to deal with the future challenges of changing climates. By using advanced software to allow for design flexibility, and the use of glazing properties and shading that is not used in the simplified overheating method.
Richard Millard, Senior sustainability Consultant at Building Energy Experts
Key Insights
- Non-standard G series house types presented higher overheating risks due to increased glazing areas and specific site orientation.
- Some units initially failed to meet TM59 criteria, prompting targeted interventions such as additional shading devices and revised ventilation strategies.
- Early-stage modelling enabled these adaptations to be incorporated from the outset, ensuring buildability and compliance without redesign delays.
- Overall, most dwellings comfortably met Part O criteria with only minor refinements, preserving the design intent while achieving regulatory compliance.
The Results
- Achieved full Part O compliance for all 260 dwellings, covering both bespoke and standard house types.
- Enabled Redrow to confidently submit detailed overheating compliance evidence to Building Control.
- Delivered clear, concise reporting that supported informed decision-making by Redrow’s design and technical teams.
- Reinforced Redrow’s commitment to delivering high-quality, comfortable, and compliant homes across their portfolio.
Client Testimonial
We’ve worked with Building Energy Experts to support Part O compliance across our developments and have been consistently impressed with their service. Their team is proactive, knowledgeable, and always on hand to provide clear guidance throughout the design and compliance process. Their reports are thorough yet easy to digest, and their input has been instrumental in helping us meet regulatory requirements without compromising on design. The quality of their reporting and technical advice has made them a valuable partner to our team.
Sean Haplin, Technical Coordinator at Redrow Homes
What’s Next?
This case study highlights the crucial role of expert overheating risk assessment in delivering compliant, comfortable new homes. Conducting early-stage overheating analysis is key to preserving design intent without compromising regulatory compliance. For complex or bespoke house types, dynamic thermal modelling provides a more accurate and flexible approach than simplified methods, making it especially valuable for large-scale developments.
If you’re planning a new build residential project, whether large or small, get in touch to discover how our team can help you achieve your compliance and design objectives with simplified overheating assessments and dynamic thermal modelling.
