How much is a very basic loft conversion?
So you're thinking about a loft conversion in the UK in 2025, just the basics. You're probably looking at somewhere between £20,000 and £30,000. That gets you a simple roof light job—Velux-style windows—in your average three-bed semi. We're talking insulation, one window, plastering, a proper staircase, standard electrics. Nothing fancy. Just enough to turn that dusty space into a spare bedroom or somewhere to work. No messing with the roof line.
What factors determine the cost of a basic loft conversion?
Honestly, the price can bounce around a fair bit. The biggest thing is what type you go for. A roof light conversion, where the windows sit flush with the tiles, is your cheapest bet. But if you start thinking about a dormer? That's different money. Dormers start around £35,000 and can easily hit £45,000 plus. Then you've got the loft size, the state of your existing roof, how much builders charge in your area, and all that building regs stuff. It adds up.
What is included in a basic loft conversion package?
A simple package should cover the essentials:
- Steel beams if they're needed to hold up the new floor
- New timber joists and chipboard flooring Insulation meeting current building regs—usually 100mm between joists and another 100mm on top
- A couple of roof windows, Velux or similar
- A fixed staircase with basic handrails
- Plasterboard and a skim finish on walls and ceiling
- Basic electrics—lighting, sockets, a smoke alarm
- Building regs approval fees, which are typically £500 to £1,000
How much does a basic loft conversion cost per square metre?
Per square metre, you're looking at £1,000 to £1,400 for a basic conversion. That's way cheaper than a dormer, which can run £1,800 to £2,500 per m². So grab a tape measure, work out your loft floor area. Say it's 25m²—at £1,200 per m², that's £30,000. This assumes nothing crazy goes wrong, like discovering the roof trusses need replacing.
What are the hidden costs of a basic loft conversion?
Oh, there are always surprises. You'll need a structural engineer's survey, £300 to £600. Party wall agreements with neighbours? That's another £500 to £1,000 each. If you've got water tanks up there, you might need to move them or switch to a combi boiler, which is £1,500 to £3,000. Fire safety stuff—fire doors, an escape route—can add £500 to £1,500. My advice? Keep back an extra 10-15% for all the stuff you didn't see coming.
Basic Loft Conversion Cost Breakdown Table
| Component | Estimated Cost (Low) | Estimated Cost (High) |
|---|---|---|
| Structural steel and floor joists | £3,000 | £5,000 |
| Roof windows (2x standard) | £,500 | £2,500 |
| Staircase and landing | £1,500 | £3,000 |
| Insulation and plastering | £2,000 | £3,500 |
| Electrics and lighting | £1,000 | £2,000 |
| Labour (builder and trades) | £8,000 | £12,000 |
| Building regulations fees | £500 | £1,000 |
| Total Estimated Cost | £20,000 | £30,000 |
Expert Insights: Getting the Best Value
"A roof light conversion is the cheapest way to add a bedroom, but don't go cheap on insulation and fire safety. Good insulation keeps your heating bills down and actually adds value. Get at least three quotes from local builders and check their past work. A basic conversion done properly can bump your property value by 10-15%."
Checklist: Before You Start a Basic Loft Conversion
- Check you've got enough head height—minimum 2.2m at the highest point
- Make sure you don't need planning permission (roof light conversions are usually fine under permitted development)
- Get a structural engineer to look at your existing roof
- Budget for building regulations approval—it's not optional
- Sort out party wall stuff with your neighbours
- Figure out where the staircase goes—it steals space from the floor below
- Get at least three detailed quotes from decent builders
- Set aside 10-15% for things that go wrong
Frequently Asked Questions
Do I need planning permission for a basic loft conversion?
Usually not. A basic roof light conversion is considered permitted development as long as you stay within certain limits, like volume allowances. But you still need building regs. If you're in a conservation area or a listed building, check with your local planning authority—different rules apply there.
Can I do a basic loft conversion myself to save money?
You can do some bits yourself, but structural work, electrics, and the staircase need pros. Building regs are strict, and messing up costs more in the long run. Most people hire a builder for the big stuff and only DIY the painting. You might save 5-10%, but honestly, the risk is high.
How long does a basic loft conversion take?
A basic one takes about 4 to 6 weeks. That covers the structural work, windows, insulation, plastering, and final touches. Delays happen if there are surprises in the roof or if materials take ages to arrive.
Will a basic loft conversion add value to my home?
Yeah, a good one can add 10-15% to your property value, especially if it's an extra bedroom. In many UK markets, you get your money back when you sell. But a shoddy job? That can hurt the value. Quality matters.
What is the cheapest type of loft conversion?
The roof light, or Velux, conversion is the cheapest, at £20,000 to £30,000. Windows sit flush with the roof, no changes to the roof shape. It works best if your loft already has decent head height and a simple layout.
Resumen breve
- Precio base: Una conversión básica de buhardilla con claraboyas cuesta entre 20.000 y 30.000 libras en el Reino Unido.
- Incluye: Aislamiento, escalera fija, ventanas de tejado, electricidad básica y acabados de yeso.
- Factores clave: El tamaño del ático, la estructura del tejado y los honorarios del arquitecto afectan al coste final.
- Valor añadido: Una conversión bien hecha puede aumentar el valor de la propiedad entre un 10 y un 15%.
