Adding a bedroom to your home can feel like the perfect solution when you need more space. Whether it is for a growing family, guests, or simply to boost your property’s value, a bedroom extension can transform both your home and your lifestyle. The big question many homeowners have is: how much does a bedroom extension cost?
The cost will depend on many factors such as size, location, materials, and whether you add luxury features like an ensuite. In this guide, you will find a clear breakdown of UK bedroom extension prices, real-world examples, tips to save money, and how to plan your project from start to finish.
By the end, you will know exactly what to expect, how to budget, and how to avoid costly mistakes.
Quick Answer: Average Bedroom Extension Cost in the UK
In the UK, a bedroom extension can cost anywhere from £20,000 to over £90,000. A simple single-storey bedroom extension is at the lower end, while a large master bedroom with an ensuite and high-end finishes will be at the higher end.
Here is a quick guide to typical price ranges:
| Extension Type | Typical Cost Range |
| Small single-storey bedroom | £20,000 – £35,000 |
| Medium single-storey bedroom | £30,000 – £50,000 |
| Large master bedroom extension | £40,000 – £80,000 |
| Bedroom with an ensuite | £40,000 – £90,000 |
| Two-storey bedroom extension | £35,000 – £100,000+ |
Key Factors That Affect the Cost
Several factors will influence how much you pay for your bedroom extension:
1. Size and Layout
The bigger the space, the more materials and labour are needed. A compact guest bedroom will be much cheaper than a large master suite.
2. Location
Labour rates vary across the UK. London and the South East generally cost more, while rural areas can be cheaper.
3. Materials
High-quality bricks, windows, flooring, and finishes increase costs. Standard materials can help keep your budget in check.
4. Labour
Builder, electrician, plumber, and decorator fees all add up. Skilled tradespeople are worth the investment for a long-lasting result.
5. Complexity
Features like vaulted ceilings, bespoke wardrobes, or an ensuite with premium fittings will push the cost higher.
Types of Bedroom Extensions and Their Costs
Different bedroom extension styles come with different price tags:
Single-Storey Bedroom Extension
- Cost: £20,000 to £50,000
- Ideal if you have space at ground level.
- Cheapest option for adding a room, but may require sacrificing garden space.
Two-Storey Bedroom Extension
- Cost: £35,000 to £100,000+
- Adds space both upstairs and downstairs.
- Costs more due to structural support, roofing changes, and additional internal work.
Bedroom with Ensuite
- Cost: £40,000 to £90,000
- Includes plumbing, tiling, and bathroom fixtures.
- Great for privacy and home value, but comes with extra installation and material costs.
Loft Conversion to Bedroom
- Cost: £25,000 to £60,000
- Makes use of unused loft space.
- It can be cheaper than a full extension but may require significant structural work.
Detailed Cost Breakdown
To understand your budget better, here is a typical cost breakdown for a bedroom extension:
| Cost Area | Typical Cost Range |
| Builders | £1,200 – £1,800 per week |
| Electrician | £35 – £55 per hour |
| Plumber | £35 – £55 per hour |
| Plasterer | £150 – £200 per day |
| Carpenter | £150 – £200 per day |
| Architect | 5% – 15% of the build cost |
| Bricks & Blocks | £800 – £1,200 per 1,000 units |
| Windows | £200 – £850 each |
| Doors | £250 – £1,000 each |
| Insulation | £20 – £100 per unit |
| Flooring | £10 – £100 per m² |
| Planning Permission | Around £200 |
| Building Regulations | £200 – £1,500 |
| Waste Removal | £150 – £450 |
Real-World Budget Examples
Example 1: Basic Single Bedroom
- Size: 3m x 3m
- Standard bricks, basic carpet, no ensuite
- Labour from local builders
Estimated cost: £23,000
Example 2: Mid-Range Master Bedroom
- Size: 4m x 5m
- Quality finishes, large windows, fitted wardrobe
- Some bespoke carpentry
Estimated cost: £45,000
Example 3: Luxury Master with Ensuite
- Size: 5m x 6m
- High-end flooring, premium bathroom fixtures, designer lighting
- Full architectural service
Estimated cost: £85,000
Hidden Costs to Watch Out For
Many homeowners forget to budget for these:
- Site clearance before work begins
- Upgrading your electrical panel for extra load
- Landscaping after construction
- Temporary accommodation if the work disrupts your home
- Contingency fund (10-20% of total cost) for unexpected issues
How to Save Money Without Sacrificing Quality
- Get at least three quotes from reputable builders.
- Choose standard sizes for windows and doors to avoid custom manufacturing costs.
- Reuse existing materials where possible.
- Plan to avoid mid-project changes.
- Do some decorating yourself after the main build is complete.
Timeline: From Idea to Finished Bedroom
- Planning & Design: 4-8 weeks
- Approvals & Permits: 2-6 weeks
- Construction: 8-16 weeks, depending on size and complexity
- Finishing & Furnishing: 1-3 weeks
Return on Investment
A well-planned bedroom extension can increase your property value by 10 to 15 percent. Adding an ensuite can make your home more appealing to buyers, potentially speeding up a sale.
Mistakes to Avoid
- Underestimating the total cost
- Skipping a structural survey
- Choosing the cheapest builder without checking references
- Ignoring building regulations
- Failing to plan for hidden expenses
Step-by-Step Planning Checklist
- Decide on the type and size of bedroom extension.
- Set your budget, including a contingency fund.
- Hire an architect or designer for plans.
- Get planning permission if required.
- Obtain multiple builder quotes.
- Agree on a written contract with timelines and payment stages.
- Prepare your home for building work.
- Monitor progress and keep in touch with your contractor.
- Arrange inspections for building regulations compliance.
- Complete decorating and furnishing.
Final Thoughts
When asking how much a bedroom extension costs, the answer will always depend on your goals, budget, and the level of finish you want. By understanding all the cost factors, planning carefully, and allowing for a realistic budget, you can create a beautiful new space that improves your home and lifestyle.
Whether you want a simple guest room or a luxury master suite, investing in quality materials, skilled labour, and proper planning will pay off in comfort and value for years to come.
