I Want to Build an Extension – Where Do I Start?
- Rosenkelly Architectural Design
- Oct 23
- 3 min read
Thinking about extending your home in Dorset? Whether you're looking to add a kitchen-diner, an extra bedroom, or just more usable living space, a home extension is a smart way to make your home work harder for you. But if you’ve never done this before, it can feel overwhelming. Where do you even begin?
At Rosenkelly Architectural Design, we guide homeowners across Dorset through this process every day. Here is a simple breakdown of how to start your home extension project with confidence.
1. Define Your Goals and Budget
The first step is to understand why you want to extend.
Are you creating space for a growing family?
Do you want a better kitchen or living area?
Are you investing in the long-term value of your home?
Once you know your goals, start thinking realistically about your budget. Even a rough idea will help shape what is possible and where to begin.
2. Find Out If You Need Planning Permission
In many cases, smaller extensions can be built under Permitted Development Rights, which means you may not need planning permission. However, in Dorset, this depends on your property's location, the size of the extension, and whether your home is in a conservation area or near a protected landscape.
At Rosenkelly, we assess this as part of our paid initial visit, which includes a desktop study, local planning review, and a written quotation. This fee is deducted from the total cost if you choose to proceed with us.
3. Appoint an Architect Early
An experienced architect brings more than just design drawings. We help you:
Visualise your idea
Navigate local planning policies
Avoid mistakes that could cost you later
Coordinate with structural engineers and builders
Provide Building Regulations drawings for full compliance
Rosenkelly Architectural Design is known across Dorset for being cost-efficient, highly responsive, and practical. We work with clients who want clear advice and dependable support.
4. Understand the Process Step by Step
Here’s a simplified version of what to expect:
Initial Consultation – A short call or email exchange to understand your aims
Site Visit – Optional but recommended. Helps confirm what's possible
Measured Survey – We take detailed measurements
Design and Planning Drawings – For planning applications if required
Building Regulations Drawings – Technical design for construction
Construction or Tender Stage – We can assist or advise if needed
You do not have to commit to the entire process at once. We structure our appointments by stage so you can move at your own pace.
5. Don’t Overlook Building Regulations
Even if planning permission is not required, you will still need Building Regulations approval for most home extensions. This ensures your extension is structurally safe, energy-efficient, and legally compliant.
We handle this process for you by coordinating with a structural engineer and submitting documents to Building Control. Everything is clearly labelled and prepared to avoid delays.
6. Visualise Before You Build
We also offer 3D modelling and render services if you want to see your new space before construction begins. This is ideal for clients who want to make confident decisions early or plan to sell with planning permission.
Working With Rosenkelly
We are a Dorset-based architectural practice offering clear, professional advice at every stage. We are known for:
Honest pricing with no surprise fees
A straightforward process from start to finish
Hyper-local knowledge of planning in Weymouth, Portland, Dorchester and across Dorset
Clear appointment letters that define scope, responsibilities, and costs
If you're looking to build an extension the right way, we are here to help.
Let’s Get Your Project Started
Ready to explore your extension ideas? Contact Rosenkelly Architectural Design for a consultation. We will help you understand what is possible, explain your next steps, and prepare a written quotation.
