Planning a home extension is one of the most exciting projects a homeowner can undertake. Understanding the costs involved is crucial for effective budgeting.
Average Extension Costs by Type
- Single storey rear extension: 1,800, 2,500 per m
- Double storey extension: 1,500, 2,200 per m
- Wrap-around extension: 2,000, 2,800 per m
- Side return extension: 1,500, 2,500 per m
- Orangery/Garden room: 2,200, 3,000 per m
A well-planned extension can add 10 to 20% to the value of your property, often making it one of the best investments you can make in your home.
What Affects the Cost?
1. Size and Footprint
The larger the extension, the higher the total cost, though the cost per square metre often reduces as the project gets bigger.
2. Structural Complexity
Extensions that require steel beams, underpinning, or complex foundation work will cost more. Removing load-bearing walls requires structural steel.
3. Quality of Finishes
Basic finishes cost around 200 per m, while high-end specifications can reach 500+ per m.
4. Planning and Building Regulations
Budget approximately 2,000, 4,000 for professional fees including planning and building control.
5. Site Access
Difficult access can increase costs due to specialist equipment or manual handling of materials.
Hidden Costs to Budget For
- Party wall agreements (700, 1,500 per neighbour)
- Temporary accommodation if required
- Landscaping and making good the garden
- Utility connections and drainage
- Internal decoration and furnishing
- Contingency fund (10 to 15% of total budget)
How to Get the Best Value
- Get multiple quotes, but don't automatically choose the cheapest
- Check credentials, ensure your builder is fully insured
- Plan thoroughly, changes during construction are expensive
- Be realistic, allow a proper contingency budget
- Consider timing, starting in spring reduces weather delays
Get a Free Quote
At Cheadle Construction, we provide detailed, fixed-price quotations following a free site survey. Call 0161 218 9616 or request a free quote online.
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