Cardiff Architects
Residential and Commercial Architecture Services
Cardiff Architects with Real Knowledge of the City
Dennis Hellyar Architects is a RIBA chartered practice and a team of Cardiff architects serving homeowners, businesses, housing associations and community organisations across the city.
We deliver house extensions, new builds, commercial projects and planning applications, bringing the same care, expertise and local knowledge to every brief. Our studio is based in Barry, just a short drive from Cardiff, and we have been working across the city since the practice was founded in 2013.
With over a decade of architectural project experience across the city, we understand how Cardiff Council approaches planning applications, what matters in a conservation area in Pontcanna versus a standard residential zone in Cathays, and how to prepare proposals that move forward rather than stall.
Whether you are a homeowner in Penarth looking to extend, a business in the city centre needing to remodel, or a housing association delivering homes at scale in Cardiff's regeneration zones, we bring the local knowledge and professional rigour your project deserves.
Cardiff Architecture Projects We Have Delivered
Here is a selection of projects our Cardiff architects have completed across the city. Each one started with a conversation.
Architectural Services for Cardiff Clients
As a team of Cardiff architects working across the residential and commercial sectors, we offer a full range of services from initial idea through to completed building. Here is what we most commonly help with:
House Extensions in Cardiff
House extensions are among the most common projects we deliver across Cardiff's residential neighbourhoods. Whether you are planning a rear extension to open up a kitchen and living space, a side return on a tight Victorian plot, or a two-storey addition to add a bedroom and bathroom, we design extensions that respond to your home's character and meet Cardiff Council's planning requirements. We work across all Cardiff postcodes and have particular experience in the city's conservation areas.
Planning Drawings and Applications
Getting planning permission in Cardiff requires more than a set of drawings. Cardiff Council has specific policies affecting everything from permitted development rights to design quality in conservation areas. We prepare professional planning drawings and supporting documents and manage the submission to Cardiff Council on your behalf, drawing on detailed knowledge of what the local authority expects.
Feasibility and Early Advice
Not sure what is possible with your Cardiff property? We offer early-stage feasibility advice for both residential and commercial clients, assessing your site, reviewing local planning constraints and giving you an honest picture of your options before you commit to anything. This is particularly useful for properties in conservation areas or with complex planning histories.
Full Architectural Services
For clients who want complete support from first idea to finished building, we offer a full architectural service. We manage the design, coordinate with engineers and consultants, handle planning and building regulations, and administer the construction contract. You have a single point of contact from the first sketch to the final handover.
Commercial Architecture in Cardiff
Alongside residential work, we deliver commercial architecture across the city for businesses, housing associations and community organisations. Our Cardiff commercial portfolio includes the Lansdowne Hospital regeneration project, one of the city's largest recent social housing schemes, and the remodelling of Techniquest on the Cardiff Bay waterfront. We understand the planning policies and commercial property landscape across the city in detail.
Award-Winning Architectural Firm
Founded in 2013 after 20 years at large practices, Dennis Hellyar Architects brings the rigour of a bigger firm with the personal service clients value most. We are registered with the Architects Registration Board and hold Certified Passive House Designer accreditation, making us well-placed to advise on energy performance and sustainability across all project types.
From residential extensions in Pontcanna to a £27M social housing regeneration scheme for Cardiff City Council, our track record speaks for itself. Our Cwrt Parc development won the Best Social Housing Award at the Building Excellence Awards 2020.
How Our Architects Work With You
If you have not worked with architects before, here is how our process typically works from first contact to completed project. Not every client needs all of these stages. We are equally happy to provide exactly the level of service your project requires.
Step 1: Initial conversation
We listen to what you are hoping to achieve. There is no commitment at this stage, just a clear conversation about your project, your property and what is realistic within Cardiff's planning framework.
Step 2: Feasibility and early advice
We assess your property, review Cardiff Council's policies and any site-specific constraints, and give you a clear picture of your options before any design work begins.
Step 3: Design development
We develop the design in close collaboration with you, using 3D models and visualisations to communicate proposals. For projects in Cardiff's conservation areas we take particular care to develop designs that will be well-received by the local authority.
Step 4: Planning drawings and submission
We prepare professional planning drawings and manage the submission to Cardiff Council on your behalf, using our knowledge of the authority to present your application as effectively as possible.
Step 5: Building regulations and construction
Once planning is approved, we can take the project through building regulations, tender and construction, remaining your single point of contact throughout the build.
Ready to get started? An initial conversation with our architects costs nothing and will give you a much clearer picture of what your project could achieve.
Cardiff Neighbourhoods We Cover
Our Cardiff architects work across the whole city. Here are the main areas where we regularly deliver projects. If your neighbourhood is not listed, get in touch and we can confirm whether we cover your postcode.
Central and Inner Cardiff
We work in Cardiff city centre, Cardiff Bay, Roath, Cathays, Adamsdown and Canton. These areas include a mix of Victorian terraces, converted properties and modern developments, many within or adjacent to conservation areas. Cardiff Council's design policies in these locations require careful handling, and our local experience makes a real difference to outcomes.
North and West Cardiff
We cover Pontcanna, Llandaff, Llandaff North, Whitchurch, Rhiwbina, Lisvane and Radyr. These are predominantly residential areas with a mix of Edwardian, interwar and postwar housing. Pontcanna and parts of Llandaff include conservation areas with specific design requirements, and we are experienced in achieving planning approval for extensions and alterations in these locations.
East Cardiff
We work in Penylan, Cyncoed, Heath, Llanishen, Lisvane and St Mellons. These popular family neighbourhoods include a wide range of property types, from smaller terraces to larger detached homes. Extensions and loft conversions are particularly common in this part of the city and we have strong experience delivering them here.
South Cardiff and Penarth
We are well-placed to serve clients in Grangetown, Butetown and the southern Cardiff neighbourhoods, as well as Penarth and the Vale border areas, given our studio location in Barry. Penarth sits within the Vale of Glamorgan rather than Cardiff, but many clients in the area look to Cardiff architects for their projects, and we cover both.
Planning Permission in Cardiff: What You Need to Know
As Cardiff architects, understanding Cardiff Council's planning policies is central to everything we do. Here is a plain-language guide to the key things that affect most residential and commercial projects in the city.
Permitted development in Cardiff
Many smaller house extensions and alterations in Cardiff can be carried out under permitted development rights, meaning no formal planning application is needed. However, permitted development rules have specific size limits and conditions and do not apply in every situation. Properties in conservation areas, listed buildings and some newer developments may have had permitted development rights removed. We can assess your property quickly and confirm the best route forward.
Conservation areas in Cardiff
Cardiff has a significant number of conservation areas, including Pontcanna, parts of Roath, Canton, Llandaff and Cardiff Bay. Extensions and alterations in these areas are subject to stricter design requirements and tighter controls on materials and appearance. Our experience working within Cardiff's conservation areas means we know how to design proposals that satisfy the planning authority while still delivering what clients need.
The Cardiff Local Development Plan
Cardiff's Local Development Plan sets out the planning policies governing development across the city. For homeowners this affects extension size, design quality, overlooking and parking. For commercial clients it governs use classes, regeneration zones and design standards. We stay current with Cardiff's planning policies so our clients do not have to.
Common Questions About Working with Architects in Cardiff
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Look for a RIBA chartered practice or an architect registered with the Architects Registration Board. Both indicate professional standards and ongoing accreditation. It is also worth choosing Cardiff architects with direct experience of working in the city and a track record of successful planning applications with Cardiff Council. Reviewing project case studies and asking for references from past clients will give you a good sense of whether the practice is the right fit for your project.
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It depends on the size and type of extension and the specific circumstances of your property. Many extensions in Cardiff fall under permitted development and do not require a formal application. However, if your property is in a conservation area, is listed, or has had permitted development rights removed by a planning condition, you will likely need to apply. We can assess your situation quickly and clearly.
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Fees vary depending on the scope and complexity of the project. For a residential extension, fees typically cover design, planning drawings and application support. Because our studio is in Barry rather than central Cardiff, our overheads are lower and we can offer competitive fees without compromising on quality or service. We are transparent about costs from the outset and provide a clear fee proposal before you commit.
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Cardiff Council aims to determine most householder planning applications within 12 weeks of a valid submission. More complex or commercial applications may take longer. We give you a realistic timeline at the start of the process and keep you informed throughout.
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Yes. Alongside residential work, we deliver commercial architecture across Cardiff for businesses, housing associations and public sector organisations. Our Cardiff commercial portfolio includes major social housing schemes and public building remodelling projects. Get in touch to discuss your commercial brief.
If your question is not here, please visit our dedicated residential FAQs or commercial FAQs pages for more information.