Sustainable Architecture and Placemaking for Everyday People to Thrive
Dennis Hellyar Architects is a RIBA Chartered Practice based in Barry, South Wales, registered with the Architects Registration Board and accredited as Certified Passive House Designers. We bring the rigour of a bigger architecture firm with the personal service our clients value most.We work with homeowners, businesses, housing associations and community organisations across Cardiff, the Vale of Glamorgan, Swansea, Bristol and the wider South West, delivering architecture that is practical, well-designed and grounded in real knowledge of the places we work in.
We are a firm that believes good architecture should make life better in practical, tangible ways. Not just buildings that look good in photographs, but spaces that work well for the people who use them every day. Homes that genuinely improve how a family lives. Commercial buildings that help organisations do what they do better. Housing that makes places for communities to live and thrive.
Residential Architecture
We help homeowners across South Wales and the South West design homes they love. From modest single-storey extensions to full renovations and one-off new builds, we bring the same care, expertise and personal attention to every residential project. We are collaborative in our approach and understand that a good project relies on a team with a broad range of skills and knowledge. The process can feel daunting if you have never worked with an architect before. We make it straightforward.
Commercial Architecture
We work with businesses, housing associations, councils and community organisations on commercial projects of all sizes. Our commercial portfolio spans award-winning social housing, industrial refurbishments, community facilities and public building remodelling. We understand what it means to deliver on a programme, within a budget and to the satisfaction of multiple stakeholders.
Served areas
- Cardiff, Vale of Glamorgan, Swansea, Bristol, South Wales, South West
Business details
- Year established: 2013
- Employees: 4
- Licensed
- Insured
Highlights and features
- Best Social Housing Award Building Excellence Awards 2020, Vale of Glamorgan Council
- Former Sustainablity awards in Education and Health projects (BREEAM)
- Certified Passive House Designers
- Sustainability at the core of our design thinking and material choices
- The design quality and process discipline of a larger practice
- The attention to detail, personal service and cost-effectiveness of a specialist boutique studio
- Creativity at all stages - Planning, Technical, Construction and Handover
- Guidance through Planning permission, design development and construction support
- Local Knowledge That Makes a Difference
- Collaborative Approach to Design
- Reputation for Responsive, clear communication and quick turnaround on queries and changes
Associations and certifications
- RIBA Chartered Practice
- ARB Registered
- Certified Passive House Designer
Payment methods
- Cash
- Checks
- Bank transfers
Services
Architectural Services
Report
House Extension Design, Planning Drawings & Applications, Feasibility & Early Advice, For clients who want complete support, we offer a full architectural service from initial concept through to construction. We manage the design process, coordinate with structural engineers and other consultants, and administer the building contract, giving you a single, trusted point of contact throughout.
We help homeowners across South Wales and the South West design homes they love. From modest single-storey extensions to full renovations and one-off new builds, we bring the same care, expertise and personal attention to every residential project. We are collaborative in our approach and understand that a good project relies on a team with a broad range of skills and knowledge. The process can feel daunting if you have never worked with an architect before. We make it straightforward.
We work with businesses, housing associations, councils and community organisations on commercial projects of all sizes. Our commercial portfolio spans award-winning social housing, industrial refurbishments, community facilities and public building remodelling. We understand what it means to deliver on a programme, within a budget and to the satisfaction of multiple stakeholders.
Certified Passivhaus Designers
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Dennis Hellyar Architects provides Certified Passivhaus Design services for clients seeking highly energy-efficient, comfortable and sustainable buildings across Cardiff, the Vale of Glamorgan and South Wales.
We integrate Passivhaus principles from the earliest design stages, including building orientation, solar gain, insulation, airtightness, thermal bridging, high-performance windows and mechanical ventilation with heat recovery.
Using specialist Passivhaus design and energy modelling tools, we assess and refine building performance throughout the design process.
Our service can support new homes, residential developments, extensions and other low-energy buildings. By combining architectural design with detailed performance analysis, we aim to create attractive, practical buildings that are comfortable and economical to run.
We integrate Passivhaus principles from the earliest design stages, including building orientation, solar gain, insulation, airtightness, thermal bridging, high-performance windows and mechanical ventilation with heat recovery.
Using specialist Passivhaus design and energy modelling tools, we assess and refine building performance throughout the design process.
Our service can support new homes, residential developments, extensions and other low-energy buildings. By combining architectural design with detailed performance analysis, we aim to create attractive, practical buildings that are comfortable and economical to run.
Master Planning
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Feasibility studies and masterplanning, looking at placemaking and creating neighbourhoods and communities. Sustainable principles are at the heart of our projects; The site must be inherently sustainable with easy access to local amenities, an emphasis on active travel and strategic management of waste.
Conservation and Listed Building Consents
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People
Dennis Hellyar
Principal Architect
Dennis brings over 30 years of post-qualification architectural experience to the practice working largely across a broad range of sectors throughout the UK, including education, commercial, residential, healthcare and mixed-
Use regeneration projects.
He is experienced with regard to Client liaison, concept development, brief development and driving projects from inception and feasibility stage, through to detailed design stage and eventually to completion.
He designed the first BREEAM Excellent Further Education facility in the UK and the first BREEAM Excellent Healthcare Centre in Wales.
Dennis was nominated by Portsmouth School of Architecture for the RIBA Bronze Medal and led the winning entry for the RIBA ideas competition to regenerate Hereford Buttermarket, March 2011.
Use regeneration projects.
He is experienced with regard to Client liaison, concept development, brief development and driving projects from inception and feasibility stage, through to detailed design stage and eventually to completion.
He designed the first BREEAM Excellent Further Education facility in the UK and the first BREEAM Excellent Healthcare Centre in Wales.
Dennis was nominated by Portsmouth School of Architecture for the RIBA Bronze Medal and led the winning entry for the RIBA ideas competition to regenerate Hereford Buttermarket, March 2011.
Jesus Ramos Munoz
Senior Architect
A licensed architect in the UK and Spain, Chuso has extended our 3D modelling capabilities by drawing on the latest in design technology. He has expertise in design principles paired with experience managing information systems across residential and commercial projects
Chuso is also a Certified Passivhaus Designer
Chuso is also a Certified Passivhaus Designer
Callum Richards
Architectural Technician
Martin Coles
Architectural Assistant
Photos
Reviews (19)
Diana Johnson
Jul 18, 2026
Jen Pugh
Jun 29, 2026
A big thank you to Dennis and his team for the help and advice they gave for my new balcony. Although a relatively small job for them, they provided support and advice; coming up with ideas and suggestions throughout. Their drawings and specifications were excellent and I could easily picture the final result. They kept me informed of progress at all times. Im very pleased with the outcome.
Ken Briggs
Jun 29, 2026
I invited David Hellyar to my come to my home to discuss an appointment for an extension to the property. David is very professional and has significant knowledge in his field, I knew almost immediately that this would be a good fit. From my initial brief and hand sketches, his practice developed drawings, with one or two iterations at my request, and provided a package for a planning application. David made the application on my behalf along with the necessary building control requirements. I also, as an addition, asked David to source and co-ordinate with a Structural Engineer so as to provide the structural calculations for Building Control approval. I chose this route in preference to an appointed builder carrying out calculations. Planning was approved without any issues. The package provided by David was clear and concise and allowed the builder to construct without any problems. I can therefore recommend David as a thoroughly reliable and trustworthy Architect.
Nick Gale
Jun 26, 2026
Don Carroll
Jun 18, 2026
I wholeheartedly recommend Dennis and the team. They were with us for every step of our design journey. Dennis helped us define what we wanted and gently explained what we could achieve given the constraints imposed by our site, budget and planning requirements. Throughout the process the team made sure we understood where things were at so the only surprises were the ones we sprung on them. Love their work!
Alwyn Lloyd
May 22, 2026
Jack Crook
May 22, 2026
Alan Salisbury
May 19, 2026
We are delighted to be able to leave a 5 star review with regard to the design work Dennis Hellyar and his team recently completed for us. Dennis with his knowledge and expertise was able to creatively provide us with a variety of options to re-configure and maximise space within our planned extension. We could never have imagined the possibilities without his input. In particular he listened intently and was sensitive to our preliminary and emerging ideas. His advice was clear and always with our interests in mind.
We thoroughly recommend him without reservation.
Alan and Jane Salisbury
We thoroughly recommend him without reservation.
Alan and Jane Salisbury
Steve Martin
May 18, 2026
Nathan Jones
May 16, 2026
Weve had a brilliant experience working with Dennis and the team at Dennis Hellyar Architects. The visuals they created were incredibly impressive and really brought our ideas to life. Dennis has been supportive, approachable and generous with his advice throughout the process, and its clear he genuinely cares about achieving the best outcome for his clients.
A special mention as well to Jesus and Callum both were fantastic to deal with, professional, friendly and clearly very talented. Their input made the whole experience even smoother.
Were very grateful for all the work so far and would happily recommend the whole team to anyone looking for a reliable, creative and clientfocused architectural practice. Lynne & Nathan
A special mention as well to Jesus and Callum both were fantastic to deal with, professional, friendly and clearly very talented. Their input made the whole experience even smoother.
Were very grateful for all the work so far and would happily recommend the whole team to anyone looking for a reliable, creative and clientfocused architectural practice. Lynne & Nathan
Mrs. C.
May 16, 2026
Gerry Wiggins
May 13, 2026
Elizabeth Treasure
Apr 23, 2026
Dennis Hellyar Architects have provided me with outstanding service through a house renovation and extension. They worked through several iterations of the design and then obtained planning permission, the contract and have been very supportive during the post contract phase. The work is almost finished and I am delighted with the result. I have never done anything like this before and I could not have done it without them. Thank you!
Camila Penazzo
Apr 20, 2026
We had a great experience with this Dennis and Jesus for our measured survey. They were highly responsive, punctual, and very efficient with the turnaround. Beyond the core service, they were also incredibly helpful in suggesting other professionals to support us through the wider process. Would definitely recommend.
Lucas Elsner
Mar 06, 2026
I met Dennis in the context of a research project on home extensions involving HCU Hamburg and Cardiff University. We approached him because of his extensive professional experience, particularly in developing residential projects in South Wales. Dennis kindly took the time to contribute to our research, generously sharing his valuable expertise and insights into the residential projects he has worked on. He also provided us with his broader perspective on the development of the home extension and refurbishment industry.
Robert Chapman
Feb 18, 2026
Excellent service by the design team on our current project in Bridgend.
Our client changed their minds on the extension we are building from a warehouse into manufacturing facility. Following our DTM meetings DHA revised the drawings in no time not for it to affect our build programme and excellent communication throughout.
Hopefully we'll work together again in the future and I would highly recommend them.
Our client changed their minds on the extension we are building from a warehouse into manufacturing facility. Following our DTM meetings DHA revised the drawings in no time not for it to affect our build programme and excellent communication throughout.
Hopefully we'll work together again in the future and I would highly recommend them.
G. Batte
Nov 04, 2025
Dennis was very helpful, his attention to detail was impressive and experience showed in his knowledge for the work that needed compliant designs for.
The architectural drawings supplied, showed so much detail in many ways.
I would highly recommend Dennis Hellyar Architects for all architectural designs required.
The architectural drawings supplied, showed so much detail in many ways.
I would highly recommend Dennis Hellyar Architects for all architectural designs required.
Mark Wray
Jul 04, 2025
Dennis and his team have completed several projects for us, all delivered with exceptional service and attention to detail. Their professionalism, creativity, and ability to bring our ideas to life have consistently exceeded our expectations. From initial concept through to final execution, Dennis has been a pleasure to work withreliable, responsive, and always committed to delivering high-quality results
Ashley Rees
Jun 26, 2025
Dennis Hellyar Architects have delivered multiple successful projects for our Association. Their team is creative, detail oriented, and easy to work with. Every project has been completed to a high standard, on time, and with clear communication throughout. A trusted and valued partner were always happy to recommend.