Budgeting: How much does a loft conversion cost? A budget guide
A loft conversion cost depends on the size of the loft, the type of conversion, and the stairs, windows and finishing you choose. In a worked example, a simple loft bedroom with roof windows costs about 40,000.
By Wealtie Team · 3 min read
Key takeaways
- A loft conversion cost depends on the size, type, stairs, windows and finishing.
- In a worked example, a simple loft bedroom with roof windows costs about 40,000.
- Add a contingency for surprises, since old roofs often hide problems.
- Compare the cost with moving to a bigger home before deciding.
How much does a loft conversion cost?
Turning a loft into a bedroom, office or bathroom can add space without moving house. It's also a big building project with many parts: strengthening the floor, adding stairs, fitting windows, insulating, wiring and plastering. The total depends on the size of your loft, its shape and the type of conversion. A simple conversion with roof windows costs less than one that changes the roof shape to add more headroom. In a worked example, a simple loft bedroom with roof windows costs about 40,000.
Building and planning rules vary by country and area, so check what permissions you need before you start. Most conversions also need to meet building safety standards, including fire safety and stairs.
What does a loft conversion cost?
Here's a worked example of a simple loft bedroom, in round numbers that work in any currency:
| Item | Cost |
|---|---|
| Structure and floor | 15,000 |
| Stairs | 5,000 |
| Windows and roof work | 7,000 |
| Insulation, electrics and plastering | 8,000 |
| Fees and permissions | 3,000 |
| Finishing | 2,000 |
| Total | 40,000 |
Adding a bathroom, changing the roof shape or choosing high-end finishes can push the cost much higher.
What affects the loft conversion cost?
Type of conversion
A simple conversion keeps the roof shape and adds roof windows. Bigger conversions change the roof to create more standing room, which adds space but costs much more.
Headroom and structure
Lofts need enough height to be usable. If the loft is low, or the roof structure needs changing, costs rise. A builder or surveyor can tell you early whether your loft is suitable. Paying for that advice before you commit is far cheaper than discovering a problem halfway through, and it gives you a more accurate figure to save towards.
Stairs
A proper staircase is usually needed, and finding room for it on the floor below can be tricky. Sometimes it means losing part of a bedroom or landing.
Bathroom
Adding a bathroom means plumbing, drainage and extra finishing, which adds a lot to the cost.
Fees
Architects, structural engineers, surveyors and permission fees are a real part of the budget. Don't leave them out of your first estimate.
What else adds to the loft conversion cost?
Old roofs often hide surprises, like rotten timbers or poor insulation, that only show once work starts. Set aside a contingency of about a tenth of the budget, so 4,000 in the worked example, to cover them. Other costs include decorating, flooring, furniture and blinds for the new room, plus possible extra heating. You may also need to stay elsewhere for part of the work, or pay for storage. Insurance may need updating too.
Living through the work
A loft conversion can take several weeks or months, with builders coming and going, dust and noise. Most of the work happens from scaffolding outside until the stairs go in, which keeps disruption down for a while. Once the stairs are cut through, the floor below is affected. Plan for this time, especially if you work from home or have young children. Some families take a short break during the noisiest stage, which is another cost to add to the budget. Agree working hours with the builder and ask for a rough schedule of each stage, so you know when the messiest parts will happen and can plan around them.
Is a loft conversion worth it?
Compare it with moving to a bigger home. Moving brings its own costs, like fees, taxes and removals, which can add up to a lot. If a conversion gives you the space you need for less, and you like where you live, it can be good value. The home extension budget covers another way to add space, which can be worth comparing.
Get several quotes
Ask at least three builders who specialise in loft conversions for detailed, written quotes. Check what's included, from stairs to decorating, and ask to see past work. A clear contract with stage payments protects you if things go wrong.
How do you save for a loft conversion?
Divide the total, including the contingency, by the months until you want to start. For 44,000 over four years, that's about 900 a month. A sinking fund for the project keeps the money separate. The home renovation budget covers planning a big project, and the home maintenance budget covers keeping the rest of your home in good shape.
How do you plan a loft conversion in Wealtie?
Add a project category to your expense categories and set a budget for it, so you can see how each stage payment and purchase compares with your plan as the work goes on.
Questions people ask
In a worked example, a simple loft bedroom with roof windows costs about 40,000, including structure, stairs, windows, insulation, fees and finishing.
Changing the roof shape, low headroom, adding a bathroom, complex stairs and high-end finishes.
About a tenth of the budget. In a worked example, 4,000 on a 40,000 conversion.
It can be, once moving fees, taxes and removals are counted. Compare both before deciding.
This article is general information, not financial, tax or legal advice. Your situation is your own; check the numbers that apply to you before you act on them.
