12/10/2026
🏡 🧱 HOW MUCH DOES A HOME EXTENSION REALLY COST BEFORE YOU EVEN LAY A BRICK? 🧱💷
When people think about building an extension, they often focus on the cost of the builder, bricks and materials, without consideration for the bigger picture of the project as a whole.
But there are several costs you need to budget for before construction even begins!
Here’s a typical breakdown of the costs you could face when planning a home extension or renovation 👇
📐 1. Architectural Design, Planning & Building Regulations
£1,800–£4,000+
Feasibility assessment, design work, architectural drawings, planning application preparation, planning statement preparation and detailed Building Regulations drawings and specifications.
🏛️ 2. Council Planning Application Fee
£600–£1,000+
The fee payable to the council for determining your planning application, where planning permission is required.
🧱 3. Structural Engineer
£500–£1,500+
Structural calculations and beam designs may be required for steelwork, large openings and other structural elements.
🌳 4. Surveys & Specialist Reports
£300–£1,500+
Depending on the site, you may need a topographical survey, drainage survey, tree survey or other specialist reports.
🏢 5. Building Control Fees
£1,000–£1,500+
Fees payable for checking the Building Regulations application and carrying out the necessary site inspections to get your build signed off as compliant
💰💰💰💰SO, WHAT COULD THAT ADD UP TO?
You could be looking at approximately £4,200–£9,500+ before the building work gets underway.
And that's before accounting for the actual construction, kitchen and bathrooms, flooring, decorating and landscaping!
💡 My advice? Plan the whole project, not just the build.
At Duke Design Services, we help homeowners turn their ideas into a practical, well-considered design, with planning and Building Regulations support to help them move towards construction with confidence.
Thinking about extending your home? Get in touch before you start spending money on the build.
📞 07450 607284
📧 [email protected]
🌐 www.dukedesign.org
⚠️ These figures are indicative budget allowances, not fixed quotations. Costs vary depending on the size and complexity of the extension, the property, the location and the level of professional input required. Some services may be combined, and not every project will need every item.
Professional architectural design, planning drawings and technical design services across Greater Manchester, the North West, Lake District and North Wales.