Architects in South Wales specialising in house extensions and planning drawings
We help homeowners across Cardiff, the Vale of Glamorgan, Swansea and Bristol design extensions and prepare planning drawings — guiding you from first ideas through to planning approval.
Reimagining Home
Planning a house extension can feel complicated - from understanding what’s possible to getting the right drawings in place.
At Dennis Hellyar Architects, we help homeowners across South Wales design extensions and prepare planning drawings, making the process clear and straightforward from the outset.
Whether you’re at an early idea stage or ready to move forward, we guide you through each step with practical advice and well-considered design.
Residential & Commercial
Residential Architecture
We work closely with homeowners to design extensions, renovations and new homes that improve how you live, while adding long-term value to your property.
Commercial Architecture
Alongside residential work, we also deliver commercial projects for private clients, organisations and community sectors across South Wales and the South West.
Core Services
House Extension Design
We design high-quality house extensions tailored to your property, helping you make the most of your space while responding to planning requirements.
Planning Drawings & Applications
We prepare clear, professional planning drawings and support you through the submission process, helping you move your project forward with confidence.
Feasibility & Early Advice
Not sure what’s possible? We assess your property and provide clear guidance so you can make informed decisions before committing further.
Full Architectural Services
From initial design through to construction, we offer a complete architectural service depending on your needs.
Process
How we help you get your extension approved
We listen to your ideas and requirements
We design your extension
We prepare planning drawings
We guide you through submission
You move forward with clarity and confidence
Choosing the right architect isn’t just about design - it’s about making the process simple and getting results.
Experienced in residential extensions across Cardiff and South Wales
Clear, straightforward advice without unnecessary jargon
Strong understanding of local planning policies and constraints
Focused on practical, buildable design solutions
Friendly, collaborative approach from start to finish
Sustainability
We believe good design should also be responsible.
Our work incorporates sustainable design principles where appropriate, helping to improve energy performance, reduce environmental impact and create comfortable, efficient spaces.
Areas we Work
We work with homeowners across South Wales and the South West, including:
This local experience gives us a strong understanding of planning requirements across different authorities.
FAQ
Do I need an architect for a house extension?
While not always required, working with an architect helps ensure your extension is well-designed, compliant and more likely to gain approval.
Do I need planning permission for an extension?
Some extensions fall under permitted development, but many require planning approval. We can advise based on your property and location.
How much do extension drawings cost?
Costs vary depending on the size and complexity of your project. We provide clear guidance early so you know what to expect.
