Builders
Carpenters
Electricians
Flooring Specialists
Gardeners
Handymen
Heating Engineers
Painters & Decorators
Plasterers & Renderers
Plumbers
Roofers
Tilers
myLoft Conversion Cost
At a Glance
- The average cost of a loft conversion is £40,000.
- It will take about 7 weeks to complete.
- A breakdown of pricing information for different types of loft conversions.
- How long the job will take and a general overview of what the job involves.
- Building regulation and planning permission for a loft conversion.
Get free estimates
Are you a trade? Get more work today!
A loft conversion is one of the smartest ways to add extra space and real value to your home. But before you start planning, it’s important to understand the costs.
This guide breaks down the average prices for each type of loft conversion, explains what’s involved, and highlights the common pitfalls to avoid.
Even if you're only exploring your options it’s worth getting several quotes early in the process. This helps you establish a realistic budget, compare like-for-like offers, and secure a reputable builder before schedules fill up.
It's quick and easy to get free, no-obligation quotes from loft conversion specialists near you using MyJobQuote.
£40,000
Table of Contents
- How Much is a Loft or Attic Conversion?
- Loft Conversion Prices
- Loft Conversion Cost by Type
- Loft Conversion Labour Costs and Timescales
- Additional Loft Conversion Costs
- Factors That Impact Loft Conversion Costs
- Do I Need an Architect for a Loft Conversion?
- Does a Loft Conversion Need a Staircase?
- What's Involved in a Loft Conversion?
- How to Keep Down Costs of a Loft Conversion
- Can I Build a Loft Conversion Myself?
- Do You Need Planning Permission for a Loft Conversion?
- Building Regulations For Loft Conversions
- Party Wall Agreements for Loft Conversions
- Possible Issues You May Come Across When Converting a Loft
- Checklist: Hiring a Loft Conversion Specialist
- FAQs
How Much is a Loft or Attic Conversion?
In 2025, the average cost of a loft conversion in the UK is around £40,000. This figure represents a typical dormer conversion, including labour and materials. Prices can range from £20,000 for a simple Velux conversion to £80,000 or more for larger or more complex designs such as mansard or hip-to-gable conversions.
The total cost depends on the size of your loft, the conversion type, the specification and finish, and your location. In high-cost areas like London and the South East, expect to pay closer to £1,750 to £2,500 per m². For properties in other parts of the UK, average prices usually remain closer to £1,200–£1,800 per m².
The table below shows typical costs for each type of loft conversion based on the overall project, and per per m², to help you plan your budget and compare quotes.
| Type of Conversion | Average Cost (30m²) | Average Cost (50m²) | Cost per m² | Typical Timescale |
|---|---|---|---|---|
| Velux Loft Conversion | £15,000-£20,000 | £20,000-£30,000 | £500-£700 | 4-6 weeks |
| Dormer Loft Conversion | £35,000-£50,000 | £45,000-£60,000 | £1,150-£1,700 | 6-9 weeks |
| Hip-to-Gable Loft Conversion | £45,000-£60,000 | £55,000-£70,000 | £1,400-£2,000 | 8-10 weeks |
| Mansard Loft Conversion | £45,000-£60,000 | £55,000-£70,000 | £1,400-£2,000 | 10-12 weeks |
| L-Shaped Dormer Loft Conversion | £50,000-£60,000 | £55,000-£70,000 | £1,400-£2,000 | 9-12 weeks |
| Shell Loft Conversion* | £20,000-£40,000 | £30,000-£55,000 | £700-£1,350 | 3-5 weeks |
Want a custom price?
Post your job
When reviewing these price ranges, remember that the total cost is directly linked to the size and specification of your project. Most builders will estimate your loft conversion cost on a per m² basis, meaning the bigger the space and the higher the finish, the further up the price bracket your conversion will sit.
Bungalows, for example, often have a larger footprint (typically 50 m²), so their loft conversions typically fall within the higher end of the scale due to their overall floor area.
There are many ways to balance design choices with budget. Setting a clear plan early and comparing quotes from local loft conversion specialists will help you understand how your cost per m² changes depending on layout, materials, and finish level.
Loft Conversion Prices
The cost of a loft conversion will depend on a lot of different choices, but the two main considerations for the cost are the size of the loft you will be converting, and the type of loft conversion you will be getting.
Loft Conversion Cost per m²
The overall cost per m² for a loft conversion depends on the size, roof type, and finish level. Larger conversions generally achieve a lower cost per m² because fixed costs such as scaffolding, access, and design fees are spread over a bigger area. The table below shows the average loft conversion prices per m² based on typical build sizes in the UK.
| Size (m²) | Average Total Cost |
|---|---|
| 20 m² | £20,000–£32,000 |
| 30 m² | £26,000–£45,000 |
| 40 m² | £35,000–£55,000 |
Want a custom price?
Post your job
As a guide, most loft conversion fall between £1,200 and £2,500 per m². The average UK loft conversion is around 25 to 35m², which typically brings the total project cost to between £30,000 and £45,000 depending on the specification and location.
For more detail on how prices vary by region, see our section on regional loft conversion costs below.
Costs by Region of the UK
Where you live has a major impact on building costs. Higher demand for skilled trades, local material prices, and even site access can all influence the final quote for your loft conversion.
The table below provides a guide to the typical price ranges and cost per square metre you can expect in different regions across the UK. As a rule of thumb, prices in London and the South East are often 15 to 25% higher than in the North of England or Scotland.
| Region | Typical Cost Range | Typical Cost per m² |
|---|---|---|
| London | £45,000-£85,000+ | £1,800-£2,700 |
| South East | £42,000-£78,000 | £1,700-£2,500 |
| South West | £38,000-£70,000 | £1,550-£2,200 |
| The Midlands & East of England | £35,000-£68,000 | £1,450-£2,100 |
| The North of England | £30,000-£60,000 | £1,250-£1,900 |
| Wales | £34,000-£62,000 | £1,400-£1,900 |
| Scotland | £32,000-£60,000 | £1,300-£1,900 |
Want a custom price?
Post your job
Loft Conversion Cost Breakdown
There are a lot of jobs involved in a loft conversion.
The table below gives the cost breakdown for £40,000 conversion. This is to put in about 30m² of loft space and includes a dormer and a roof light over the new staircase. This would cover the electrics and plumbing for a master bedroom with an ensuite.
On this example, labour and project management would amount to approximately 60% of the total cost for the entire project. Around 25% would cover the cost of materials, with 8% for scaffolding and the remaining balance of 7% of the budget reserved for any unexpected additional fees.
| Job | Cost for 30m² loft |
|---|---|
| Project Management – including building control costs | £8,800 |
| Roof Coverings | £6,400 |
| Alterations to Roof Structure | £4,400 |
| Joinery – excluding staircase | £3,800 |
| Steelwork to support structural changes | £3,200 |
| Scaffolding | £3,000 |
| Plastering | £2,400 |
| Staircase | £2,000 |
| Decoration | £1,200 |
| Internal Preparation | £1,000 |
| Electrics | £800 |
| Total | £40,000 |
Want a custom price?
Post your job
Loft Conversion Cost by Type
The type of loft conversion you choose is the single biggest factor influencing the total cost and the amount of space you gain. Your decision will depend on your property's roof structure, planning permission rules in your area, and your budget.
Each type involves a different level of structural work which means the cost per m² will vary significantly. Below, we break down the main options to help you understand which is right for your home.
| Type of Conversion | Typical Cost Range |
|---|---|
| Velux (Rooflight) | £15,000-£30,000 |
| Dormer | £30,000-£60,000 |
| Hip-to-Gable | £40,000-£65,000 |
| Mansard | £45,000-£75,000+ |
| Shell Conversion | £20,000-£55,000 |
| Modular Conversion | £40,000-£80,000 |
Want a custom price?
Post your job
Velux Loft Conversion Cost
- Best for: Budgets, speed, and lofts with high existing headroom.
- Average Cost per m²: £500 to £700
A Velux conversion (or rooflight conversion) is the simplest and most cost-effective option. The work happens within the existing roofline, with no external alterations other than adding rooflight windows like those from the brand Velux. The floor is reinforced and the space is insulated and finished to create a habitable room.
The average cost of a velux loft conversion is £15,000 to £30,000.
Pros:
- ✔ Fastest & most affordable conversion
- ✔ Minimal structural work required
- ✔ Permitted development friendly (planning rarely needed)
Cons:
- ✖ Relies entirely on your existing roof height
- ✖ Creates the least amount of new usable space
Dormer Loft Conversion Cost
- Best for: Maximising headroom, adding en-suites, and the best return on investment.
- Average Cost per m²: £1,150 to £1,700
Dormer conversions are the most popular type in the UK as they offer an excellent balance of space and cost. This involves building a box-shaped structure that projects vertically from the pitched roof, creating a flat ceiling and straight walls that significantly increase usable floor space and headroom.
The average cost of a dormer loft conversion that's 30m² is £45,000, with ranges between £35,000 and £60,000.
This is more expensive than a velux loft conversion, but offers the best return on investment in terms of space gained vs. cost, and may be required if you want an en-suite.
Pros:
- ✔ Maximises usable floor space with full headroom
- ✔ High return on investment
- ✔ Adds versatile space (e.g., for bathrooms)
Cons:
- ✖ More complex and costly build than a Velux
- ✖ External structure isn't always discreet
Hip-to-Gable Loft Conversion Cost
- Best for: Semi-detached and detached homes to create large, open-plan spaces.
- Average Cost per m²: £1,400 to £2,000
Hip-to-gable loft conversions are sometimes referred to as gable-end or gable-wall conversions by builders.
In a hip-to-gable conversion, the shape of the roof is significantly altered. The sloping "hip-end" is replaced with a vertical gable wall.
The end result is that, instead of having a sloping roof on the side of the house, there will now be a vertical gable that can either be made of brick or tile.
This creates a lot of extra space. However, it only works in a semi-detached or detached property with a sloping roof. With a detached home, you can also convert both sides to create a double hip-to-gable conversion.
The average cost of a hip-to-gable loft conversion that's 20m² is between £45,000 to £70,000. This is another step-up in price when compared to average rooflight and dormer attic conversion prices in the UK.
Pros:
- ✔ Transforms a cramped hip roof into a large, open room
- ✔ Can be combined with a rear dormer for even more space
Cons:
- ✖ Only for detached, semi-detached, or end-terrace homes
- ✖ Major structural change to the roof
- ✖ High cost and complexity
Mansard Loft Conversion Cost
- Best for: Maximising all available space, premium properties, and areas with strict planning (like London).
- Average Cost per m²: £1,400 to £2,000
Mansard loft conversions involve changing the whole shape of the roof, which is essentially modified to be almost completely flat. The walls will also be almost vertical (70-degree angle) and, in most cases, dormer windows can be added.
Because Mansard loft conversions cause significant visual change to a property's exterior from these structural changes, they typically require the owner to apply for planning permission. Whereas dormers tend to fall under permitted development, and therefore permission is not needed.
The average cost of a Mansard loft conversion that's 20m² is between £45,000 to £75,000.
Pros:
- ✔ Adds the maximum possible volume to your home
- ✔ Can create a full new storey
- ✔ Often considered more aesthetically pleasing
Cons:
- ✖ The most expensive & complex conversion
- ✖ Always requires planning permission
- ✖ Longest build time
Shell Loft Conversion Cost
- Best for: Skilled DIYers, saving on labour, and spreading the total cost over time.
- Average Cost per m²: £700 to £1,350 (for the structural shell only)
If you want to manage the budget and finish the project yourself, a 'shell' conversion is a great option. A contractor completes all major structural work, leaving you with a watertight shell. This allows you to hire your own tradespeople (electricians, plumbers) to complete the insulation, plastering, and decorating.
Think it of it a basic loft conversion, or a if you're handy with DIY yourself, then a head start on a DIY conversion.
A simple Velux shell conversion with two Velux windows is estimated to cost between £10,000 to £12,000. While a dormer shell conversion that includes a dormer and staircase is estimated to be in the range of £18,000 to £22,000.
Pros:
- ✔ Saves significant money on labour costs
- ✔ Full control over the internal finish and budget
- ✔ Lets you phase the internal fit-out costs over time
Cons:
- ✖ Requires significant DIY skill or project management
- ✖ You must coordinate all internal trades (plasterers, etc.)
- ✖ Not a 'ready-to-use' room from the builder
Modular Loft Conversion Cost
- Best for: Speed, minimising disruption, and a high-quality, factory-controlled finish.
- Average Cost per m²: £1,800 to £2,500
A modular loft conversion involves building the main structure in a factory off-site. The pre-fabricated module is then transported to your home and craned into place, significantly reducing on-site construction time and disruption. This method offers speed and predictable quality control.
The average cost of a modular loft conversion is £40,000 to £80,000.
Pros:
- ✔ Minimal on-site disruption (often 1-2 weeks)
- ✔ Predictable build quality from factory setting
- ✔ Less dependent on weather for the main build
Cons:
- ✖ Requires good site access for a large crane and lorry
- ✖ Less design flexibility than an on-site build
- ✖ Can be logistically complex to organise
Loft Conversion Labour Costs and Timescales
A loft conversion involves a mix of skilled trades, from builders and roofers to electricians, plasterers, and decorators. You can expect two to three tradespeople on site for most of the build, coordinated by a main contractor or project manager.
Timescales vary depending on access, weather conditions, and how efficiently each trade can be scheduled. As a guide, labour costs (including management) typically account for around 50% to 60% of your total budget.
Average Labour Cost & Duration by Conversion Type
The table below shows the estimated labour-only portion of the total cost for each project, along with the average build time from start to finish.
| Type of Conversion | Typical Duration | Average Labour Cost (Est.) |
|---|---|---|
| Velux Loft Conversion | 4-6 weeks | £9,000-£14,000 |
| Dormer Loft Conversion | 6-8 weeks | £20,000-£40,000 |
| Hip-to-Gable Loft Conversion | 6-8 weeks | £20,000-£35,000 |
| Mansard Loft Conversion | 8-10 weeks | £25,000-£45,000 |
Want a custom price?
Post your job
Average Cost Per Hour of Different Tradesmen
If you are managing the project yourself or hiring individual trades, their hourly rates are key. These rates will vary based on your location (e.g., London and the South East are typically 20% to 30% higher) and the complexity of the job.
| Tradesman | Average cost per hour |
|---|---|
| Builder | £20-£35 |
| Tiler | £20-£40 |
| Decorator | £20-£50 |
| Plasterer | £30-£50 |
| Plumber | £35-£45 |
| Electrician | £50-£120 |
Want a custom price?
Post your job
Additional Loft Conversion Costs
Here are a few additional costs you might come across when building a loft conversion, although please note these may not all be relevant to your specific build and prices may vary depending on the extent of the work involved:
| Item | Cost Range |
|---|---|
| Building regulations | £300–£1,000 |
| Moving a water tank | £100–£250 |
| Replacing roof tiles | £200–£600 |
| Skip hire | £150–£350 |
| Roof joists | £600–£1,200 |
| Party wall survey | £700–£1,500 |
| Architect plans | £800–£2,500 |
| Roof lantern installation | £900–£1,200 |
| Velux window installation | £1,000–£1,400 |
| Boarding and insulating loft | £1,400–£1,800 |
| New boiler | £1,800–£4,000 |
| Soundproofing | £2,000–£2,500 |
| Wet room | £5,000–£10,000 |
| Underfloor heating | £1,000–£8,000 |
Want a custom price?
Post your job
While the table above covers the standard fees, some properties have specific issues that can lead to unforeseen costs. Two additional costs you may face are:
- Asbestos Survey and Removal — If your house was built before the year 2000, there's a chance it could contain asbestos. You may need a survey (£250 to £400) and if asbestos is found and needs to be removed by a specialist, this can cost £500 to £3,000 or more.
- Bat Survey (Ecological Survey) — Bats are a protected species. If there's any evidence of them in your loft, you'll be legally required to get a bat survey before work can begin. This can cost £400 to £800 and may affect your project's timeline.
Factors That Impact Loft Conversion Costs
The total cost of a loft conversion depends on more than just the type of conversion. Several key factors influence where your project falls within the typical price range. Understanding these will help you plan an accurate budget and avoid unexpected costs.
Purpose of the Room
How you plan to use the new space is one of the biggest drivers of the internal fit-out cost. A simple, single-use room will always be cheaper than a multi-functional or specialist space.
- Office or Playroom — These are typically the most cost-effective conversions, requiring only basic plastering, standard electrics, flooring, and decoration. If you require additional plug sockets, or upgrades like integrated USB and network connections, the cost per point will be higher. Expect to pay a premium of £20 to £40 per socket for USB functionality, and £100 to £200 per point for a hardwired Ethernet network connection, as this requires extra cabling.
- Bedroom — A bedroom may require more electrical sockets and lighting options, but the main additional cost often comes from fitting bespoke wardrobes and storage solutions, which can add £2,000 to £5,000.
- Adding an En-suite Bathroom — This is usually the biggest additional expense. Plumbing typically costs £35 to £55 per hour plus materials, alongside the cost of the suite, tiling, and ventilation. A fully fitted en-suite will add £5,000 to £12,000 to the total project cost. See new bathroom cost guide for more.
- Cinema or Music Room — Creating a room for entertainment may require enhanced soundproofing in the walls and floor to prevent noise from travelling through the house. This can add £1,000 to £2,500 to the plastering and insulation costs.
- Home Gym — If you plan to use heavy equipment like weight machines or treadmills, you will need additional structural support. Your structural engineer may specify ber floor joists, which can add £1,500 to £3,000 to the structural costs.
- Studio Apartment or Self-Contained Flat —For multi-generational living or rental income (especially in London). Requires full kitchen and bathroom installation, plumbing, and fire safety measures, typically adds £15,000 to £25,000 on top of a basic conversion.
Size and Structural Choices
- Overall Size — A larger conversion requires more materials and labour, increasing the overall cost. A small single room will be significantly cheaper than a large conversion spanning the full width of your house.
- Internal Walls — If you decide to split your new loft space into multiple rooms (e.g. a bedroom and a separate office), you will need to add internal stud walls. It will cost around £850 to build and plaster a new stud wall.
Windows and Roof Finish
- Window Choices — The type of window makes a big difference. Velux-style rooflights are the most budget-friendly option, costing around £800 to £1,100 per window supplied and fitted. Dormer windows are more expensive as they involve building a structure; expect to pay £4,000 to £6,000 for each dormer window structure.
- Type of Roof Tiles — When building a dormer or changing the roofline, the new tiles need to match your existing roof. If you have premium tiles, such as slate or handmade clay, the cost will be higher than for standard concrete tiles.
Electrics and Plumbing
- Electrics — The cost of electrical work will depend on the number of fittings. While an electrician may charge £50 to £120 per hour, the total price depends on the complexity. A simple room with one light and two sockets will be far cheaper than a bedroom with multiple downlights, wall lights, a TV point, and numerous sockets.
- Plumbing — Outside of a bathroom, you may need to move existing plumbing for a water tank or add new radiators. The more complex this work is, the higher the final plumbing bill will be.
Ask a Trade
Got a question that only a tradesperson can answer? We have thousands of trades ready to answer any question you may have.
Ask your question
Do I Need an Architect for a Loft Conversion?
Whether you need an architect will depend on the contractor you choose. Many Loft conversion specialists are happy to work without an architect and rely on their own experience. This can save you a bit of money early on in the process, but ultimately it might lead to problems. Having an architect draw up plans for your loft conversion serves two main purposes.
Having an architect draw up plans for your loft conversion serves two main purposes:
- Firstly: to get plans drawn up is to ensure that the loft conversion work can be completed safely.
- Secondly: to get plans is so that you have a clear and agreed-upon vision for what the final product will look like. Without plans, it is easy for you and your contractor to be working at cross purposes.
With a set of plans drawn up, you have a clear record of what the loft conversion should look like - there will be no ambiguity whatsoever.
The cost will depend on how detailed they are, although as a guide - basic plans cost around £400 and more detailed versions can cost up to £1,500. The more detailed plans can be helpful in allowing your contractor to give you an accurate quote for your loft conversion.
What types of professionals can design a loft conversion for me?
"Get yourself a good loft architect and a decent structural engineer. These two professionals should definitely be able to help you design a loft conversion."
What are the Typical Architect and Design Fees?
The cost for a professional to draw up plans can vary widely depending on the complexity of the conversion and the level of detail provided:
- Basic Plans: For simple Velux or Dormer conversions, basic plans and designs typically cost between £800 and £1,500.
- Detailed Plans and Submissions: For complex designs like Mansard or Hip-to-Gable conversions that require planning permission, detailed architectural drawings and submission management can cost between £1,500 and £2,500.
More detailed plans are highly recommended as they provide clear direction for your contractor, ensuring you receive an accurate and consistent quote.
Does a Loft Conversion Need a Staircase?
To be considered a habitable room, a loft conversion needs a permanent staircase. If the loft is only accessible by ladder (no matter how sturdy), it cannot legally be classed as habitable.
This is set out in the building regulations, and mostly due to the fact that in the event of a fire, a fixed staircase is classed as a designated means of escape.
What is My Loft Space If It Only Has a Ladder?
It's perfectly legal to have a converted loft without a staircase, but rather than being considered a new room, it would be regarded as a 'loft room' or just additional storage space. Additionally, without full building regulations approval, you may encounter problems when you come to sell your property.
Legally you would not be able to consider it an extra room such as a bedroom, study etc.. and while it may still add some value to your home, it would not be as nearly as much as a full conversion with staircase.
| Feature | Loft Conversion (with Staircase) | Loft Room (with Ladder) |
|---|---|---|
| Legal Status | A fully compliant, habitable room | A non-habitable storage or hobby space |
| Marketing | Can be listed as a bedroom, office, etc. | Must be listed as a 'loft room' or similar |
| Building Regs Compliance | Must fully comply (fire, structure, etc.) | Does not need to meet habitable room standards |
| Safety | Designed with a safe means of escape | Not considered safe to sleep in |
| Value Added | Significant (often 20%+) | Moderate |
Want a custom price?
Post your job
How Much Does a Loft Staircase Cost?
Since a permanent staircase is an essential part of a legal conversion, its cost is a key part of your budget. The price can vary significantly based on design and complexity.
- Standard "Off-the-Shelf" Staircase: A simple, straight-flight or 'winder' staircase (to save space) typically costs £1,500 to £2,500, including installation.
- Bespoke or Custom Staircase: If you require a custom-made staircase (e.g., with special materials, glass balustrades, or a complex design to fit an awkward space), the cost can rise to £5,000 to £10,000+.
This cost is often included in a contractor's main quote, but it's important to clarify what style of staircase is included in the price.
What's Involved in a Loft Conversion?
A loft conversion is a big job with lots of steps to it.
If you hire a contractor who is able to get all their tradesmen and labourers organised without any delay, along with the weather being onside for the whole project, you can expect the work to go as outlined below.
Although this can vary depending on the size of the project and the work involved.
For example, if you're only having a shell conversion fitted, then process that include internal work or adding finishing touches can be carried out a later date. Alternatively, if you have chosen a modular conversion, there is far less work carried out onsite as everything arrives pre-fabricated.
- Week 1 - Preparation
The first step is to erect the scaffolding, along with having any materials and equipment required delivered to the site. The roof will also be opened up during this week.
- Week 2 - Roof Work
Modifications will be made to the roof if required, plus extra supports may be installed where needed. For a rooflight conversion, the windows will go in at this point and for a dormer conversion, the dormer will be constructed.
- Week 3 - External Finishing and Insulation
Any external work will be finished during this week, including construction within the roof area and if any tiles need replacing or fitting. Roof insulation will also be fitted. Internally, the loft space will be ready for any plumbing and electrical work that needs to be done.
- Week 4 - Windows and Flooring
Windows not yet installed can now be fitted, the floor laid, including any ventilation as needed. The plasterboard will be installed, and any internal walls built.
- Week 5 - Staircase and Bathroom
The staircase will go in at this point and if you are having a bathroom fitted, this can go in at the same time. You should also expect the electrics to be finished and towards the end of the week, doors hung, plaster skimmed, and the skirting fixed.
- Week 6 - Finishing Touches and Clean-Up
Any unfinished jobs will be completed during this week and if your contractor is responsible for decorating, this will be included as part of the finishing touches. Scaffolding can then be removed and the last of the waste taken away.
How much is soundproofing likely to add to the cost of a loft conversion? How much is decent soundproofing per metre?
"Somewhere in the region of £6.50 per m² using blanket soundproof insulation or between £55 and £60 using solid soundproof insulation boards (i.e., celotex)."
How to Keep Down Costs of a Loft Conversion
A loft conversion is a significant investment, but there are several smart ways to manage the budget without compromising on quality. Here are our top tips for keeping your costs down:
- Manage the Project Yourself — Instead of paying a lead contractor's project management fee, you can coordinate tradespeople and deliveries yourself if you have the time and experience. This alone can save you between £1,500 and £10,000 depending on the scale of the job.
- Opt for a 'Shell' Conversion — Get a contractor to complete the main structural work (floor, walls, windows, stairs) and then manage the internal fit-out yourself. This allows you to hire individual trades or DIY the rest, spreading the cost and saving on labour.
- Take on DIY Tasks — You can save a significant amount by handling non-structural work yourself. Even just taking on the final painting and decorating can save you up to £2,000 on painter's fees.
- Plan Meticulously in Advance — The most expensive mistakes happen when you change your mind mid-build. Work with your architect or designer to create detailed plans and finalise every decision—from socket locations to tile choices—before any work begins.
- Choose Standard Fittings and Finishes — High-end bathroom suites, bespoke fitted wardrobes, and premium flooring can add thousands to your bill. Opting for good quality, standard "off-the-shelf" products from trade suppliers is a simple way to keep costs under control.
- Get at Least Three Detailed Quotes — Never accept the first price you're given. Obtaining at least three like-for-like quotes from reputable companies will give you a clear idea of the current market rate and provide you with valuable negotiating power.
Can I Build a Loft Conversion Myself?
A loft conversion involves major structural changes to your roof and floor, must meet strict Building Regulations, and may require planning permission. Because of this, the main construction work should always be handled by qualified professionals rather than attempted as a DIY project.
Hiring an experienced loft conversion specialist or main contractor ensures:
- Structural Safety and Integrity — A professional works with structural engineers to guarantee the new floor is b enough and the roof structure is sound. This is critical for the safety of your home.
- Building Regulations Compliance — They manage the entire inspection process with the council, ensuring you receive a final completion certificate. Without this, your conversion is not legally recognised.
- A High-Quality Finish — Experienced tradespeople deliver a professional finish that's difficult to achieve with DIY, adding more comfort and value to your home.
- Speed and Efficiency — A dedicated team can complete a conversion in 6-10 weeks, a timeline that would be impossible for most DIYers working in their spare time.
However, there are some parts of the job that any confident DIYer could do:
| Job | Average Saving |
|---|---|
| Clearing out the loft space before the work starts – remove any debris or unused water tanks. | £45-£50 per m² of loft space |
| Putting insulation in between the rafters and beneath the new floor | £400-£700 |
| Laying the flooring | £10-£12 per m² of flooring |
| Building internal walls | £200-£225 per m² of wall |
| Boarding and plastering | £90-£110 per m² of wall |
| Decorating | £40-£50 per m² of loft space |
Want a custom price?
Post your job
Taking on any of these jobs will save you some money. The more you do yourself, the more money you will be able to save. If you do intend to take on some of the work yourself, make sure that you communicate this to your contractor early on. They will need to plan the rest of the workaround you.
Do You Need Planning Permission for a Loft Conversion?
In most cases, loft conversion planning permission isn’t needed and are covered by permitted development. Your architect or builder should be able to confirm this for you. However, as long as all of the following provisions apply, you should be safe.
- The total space created from all extensions does not exceed 40m³ for a terraced home and 50m³ for a semi-detached or detached home.
- The conversion will not extend beyond the existing roof slope at the front of the house.
- The maximum height of the roof is not increased.
- Similar materials are used to the existing building.
- No verandas, balconies, or raised platforms are added.
- Side facing windows are not clear glass – the view is obstructed.
- With the exception of hip-to-gable conversions, the roof extension is set back at least 20cm from the original eaves.
- The conversion does not overhang the original walls.
- Your home is not a listed building.
- Your home is not in a conservation area, World Heritage Site, or National Park.
How long after getting planning permission can we leave it until we start our loft conversion?
"Most of loft conversions can be carried out without planning permission, but you will still need to satisfy Building regulations. It's important to know whether you need planning permission before beginning. Once you've got planning permission, you have three years to start on your development unless a condition attached to the planning permission says differently. If you haven't started the development after three years, you will need to re-apply for planning permission."
Building Regulations For Loft Conversions
It is crucial to understand the difference between Planning Permission and Building Regulations. While your project may not need planning permission, all loft conversions must legally comply with Building Regulations as outlined by official resources like the Planning Portal.
These are national standards designed to ensure your new living space is safe, structurally sound, energy-efficient, and accessible. Without a final Building Regulations completion certificate, your conversion will not be legally recognised, and you may face problems when you try to sell your property.
While your builder should manage the process, the ultimate legal responsibility rests with you, as the homeowner.
What Do Building Regulations Cover?
An inspector from your Local Authority or an Approved Inspector will visit at key stages of the build to check several critical areas. These include:
- Structural Integrity — Ensuring the existing floor joists have been strengthened to support the weight of a habitable room and that any new steel beams are correctly installed and supported.
- Fire Safety — This is paramount. It includes ensuring there is a safe means of escape (which is why a fixed staircase is mandatory), installing mains-powered, interlinked smoke alarms, and fitting fire doors where required.
- Staircase Design — The new staircase must be safe, with sufficient headroom (at least 2m), a maximum pitch (steepness), and compliant handrails.
- Insulation — The conversion must meet current standards for thermal efficiency to prevent heat loss, which will improve your home's EPC rating.
- Ventilation — The new room(s) must have adequate ventilation (e.g., trickle vents in windows) to prevent condensation and ensure good air quality.
The Process and Your Final Certificate
Your builder or architect will submit an application to Building Control before work begins. During the project, inspectors will visit to sign off on each key stage.
Important: The most critical document you will receive is the final Completion Certificate. This is your official proof that all work was inspected and complies with the law. You should not make the final payment to your contractor until you receive this certificate.
Party Wall Agreements for Loft Conversions
If your loft conversion affects the party wall (the shared wall) with your neighbour, then you must inform them under the rules set out in the Party Wall Act 1996. This is a common requirement for semi-detached and terraced homes. You can find the full government guidance on the GOV.UK website.
What is the Party Wall Process?
The process is straightforward, but the timeline is important:
- Speak to your neighbour: Before sending any official notices, it's best to have an informal chat with your neighbour to explain your plans.
- Serve an official notice: You must give your neighbour written notice at least 2 months before work starts (and no more than 1 year before).
- Your neighbour responds: They have 14 days to respond. They can either agree to the work in writing or dissent (disagree). If they don't respond, it is automatically considered a dissent.
- If they dissent: You must appoint a party wall surveyor to draw up a legal "Party Wall Award" or Agreement. This document outlines the work, documents the wall's current condition, and identifies responsibility for any potential damage.
How Much Does a Party Wall Agreement Cost?
While the process can be free if your neighbour agrees, you must budget for potential costs if they dissent. These costs are for hiring a surveyor:
- Party Wall Agreement (Award): This is the main cost. If you and your neighbour use a single, agreed-upon surveyor, this typically costs £800 to £1,000.
- Complex or Disputed Cases: If each side appoints their own surveyor, you will have to pay for both. Total costs for a complex agreement in London can rise to £1,500 per surveyor or more.
How to Save Money on Party Wall Costs
The best way to save money is to maintain a good relationship with your neighbour. If you can come to an amicable, written agreement, you can avoid the main surveyor fees.
Even if they agree, it is highly recommended that you take detailed, time-stamped photos of the wall's condition before work starts. This simple step can protect both you and your neighbour and prevent disputes later.
Possible Issues You May Come Across When Converting a Loft
While planning in advance and hiring the right contractor for the job will eliminate many potential issues, there are times when you can become faced with unexpected hurdles. Some of these we've addressed below.
- Party Wall Disagreements — If your neighbour objects to the work or claims that you have caused damage to the party wall during the work you can suffer delays and legal expenses. To avoid this, you should make sure to speak to your neighbour before work begins.
- Finding Asbestos — In an older property, it is possible that you might come across asbestos in your loft space, this needs to be professionally removed by a qualified specialist.
- Furniture That Doesn’t Fit — Your choice of staircase may limit access, resulting in not being able to fit in your desired furniture. This should be taken into consideration in advance.
- Incorrect Fixtures and Fittings — As well as the size of fixtures such as baths and showers, it's important to ensure utilities are fitted in the correct place, as well as allowing space for doors etc.
- Missing Planning Permission — To avoid costly fines or having to undo any work, always check with your local council in advance if you are unsure if permission is required.
Checklist: Hiring a Loft Conversion Specialist
When you are hiring a contractor for a loft conversion, you will need to have faith in them. It is a big project and an important decision.
Here are some things to look for to help you make your decision:
- Are they qualified? Look for builders with proven experience in loft conversions and recognised credentials. Membership of the Federation of Master Builders (FMB) or registration with TrustMark helps ensure professional standards.
- Are they insured? A contractor should hold public liability insurance (at least £2 million). This protects you in case of property damage or injury during the project.
- Is waste removal included? Confirm that waste removal and disposal are included in the total cost. This covers old insulation, timber, and any construction debris generated during the build.
- Do they have positive reviews? Check their MyJobQuote profile to read feedback from previous clients. Reviews can give you insight into their reliability, communication, and quality of work.
- Can you check their past work? Ask to see photos or visit completed loft conversions if possible. This helps you gauge the standard of their workmanship and attention to detail.
- Will they handle building control? Most contractors will do this but make sure it is clearly agreed as it is your responsibility.
- What are the payment terms? Agree on payment terms before work starts. Avoid large upfront payments. A typical setup is a 10–20% deposit, with the balance paid on completion or at agreed stages.
- Do they offer any guarantee? Reputable contractors should be happy to provide a warranty or guarantee for their work, either directly or through an approved scheme.
Aim to get at least 3 quotes from loft conversion specialists near you. This will give you a clear idea of local pricing and help you find a trustworthy professional for your project.
FAQs
Do I need insurance if I convert the loft myself?
If you are planning to undertake all of the work, yourself, it is worth taking out insurance. This will cover you in case of damage to the property or any accidents while carrying out the work.
Will a loft conversion increase my house value?
A loft conversion can add up to around 20% to your home’s value, depending on the quality of the work and location. Before setting a budget, check local property prices; if similar homes sell for £350,000 and yours is worth £320,000, spending more than £30,000 may not give a full return.
Will a loft conversion affect my council tax?
Adding a loft conversion shouldn't have any initial impact on your council tax, as council tax bands are only reviewed when properties are sold or if you put in a formal request.
Can I get a grant for the insulation in my loft conversion?
There are grants available for loft insulation; however, they are mostly dependant on your personal situation. You would have to speak to your energy supplier to be certain.
Can I Have a Loft Conversion in My Bungalow?
Yes, due to their generous footprint, bungalows offer the potential to create a large second floor, often doubling the property's total living area. A typical bungalow loft conversion will cost between £30,000 to £65,000+. See our full Bungalow Loft Conversion Cost Guide.
How much does it cost to add an en-suite to a loft conversion?
Adding a fully fitted en-suite is usually the biggest additional expense and will add between £5,000 and £12,000 to the total project cost. This price range covers all plumbing, the suite, tiling, and ventilation.
