Rather than move house and pay, on average £10,000 to increase your living space, you can add an attic or dormer loft conversion to your property. It will also increase the value of your property by 15% to 20%.
The average cost of a loft conversion in the UK can fall between £20,000 and £45,000 depending on the type of conversion, the floor size, and how much strengthening your existing loft space needs to be safe. For a particularly large conversion, you could pay upwards to £70,000. On average, the building costs per m2 work out between £750 and £1800, depending on the types of conversion.
So, how will converting a loft benefit the average householder?
As the family grows, they naturally need more room. Ordinarily, this would require moving house or building an extension. But, why do that when there’s already a perfectly good space under the roof and within the existing perimeter of the building?
There are many uses for a loft conversion, but let’s concentrate on a few of the most common. Typically, you can use a loft or attic conversion for:
- Children’s bedrooms.
- Master bedroom with an en-suite toilet and shower.
- Playroom.
- Office.
- Guest room.
=> Looking for a custom house floor plan? Click here to fill out our form, a member of our team will be in touch.
We’ll look at these in more detail later on.
Comparing Quotes Could Save Up To 33%:
Topics
Loft Conversion Cost Estimates
The following table shows approximate loft conversion prices for different types. They range from small loft conversions for terraced houses, through slightly larger ones for semi-detached houses, up to the largest for detached houses.
Builders commonly give estimates or quotations excluding VAT. So, we will follow this convention. Moreover, labour costs in London and the Southeastern areas of England are generally 20% higher than elsewhere. So, if you live there, you can adjust these figures accordingly.
| Type of loft conversion | Estimated cost |
|---|---|
| Simple loft conversion (1 room) | £15,000 to £20,000 |
| Velux loft conversion | £15,000 to £20,000 |
| Dormer loft conversion | £30,000 to £60,000 |
| Hip to gable conversion | £40,000 to £65,000 |
| Mansard loft conversion | £45,000 to £70,000 |
All loft conversions must comply with the UK Building Regulations. However, we won’t talk much about those here. They are so important we’ll give them a section of their own, later on in this article.
Comparing Quotes Could Save Up To 33%:
Simple Loft Conversion
Probably, this is one of the cheapest types of loft renovation. Essentially, it consists of building a room within the existing roof space without changing the roof profile. One or two skylights for natural light and ventilation, and a basic loft conversion.
Velux loft conversion
This a simple loft conversion using Velux windows as ventilation and emergency exit. The windows have many different styles, sizes and functions. And, it’s worthwhile choosing one that suits your requirements. The manufacturer ensures that all Velux windows comply with, and has features to assist installation, complying with the UK Building Regulations.
Dormer loft conversion
These are loft conversions incorporating ‘dormer windows’. The windows are installed vertically from the plane of the pitched roof, with a small separate roof joining the top of the window to the main roof. The simple, but necessary alterations needed to incorporate the windows provide increased floor space and additional headroom.
Hip to gable conversion
A hip roof is one that has 4 sloping surfaces. This type makes building a loft conversion very difficult as with a hipped roof there isn’t much space. And, there is very little head room because of the sloping ceilings. Perhaps, more importantly, they aren’t strong enough to support the joists.
The Hip to Gable loft conversion removes one or both opposite hipped sloping roof surfaces while extending the wall upwards. This forms a gable wall of the same height as the ridge. As you would expect, this type is expensive, very challenging, and needs a roofing conversion specialist involved at the planning stage.
Comparing Quotes Could Save Up To 33%:
Mansard loft conversion
Mansard roofs traditionally have two different pitches on each roof slope. The Mansard loft conversion also has two pitches. This loft conversion typically occurs at the rear of the property and extends across the entire roof. It either has a flat or slightly pitched roof, while the front surface slopes backwards at an angle of 72 degrees. They are suitable for all house types; detached, semi-detached, terraced, and bungalows. So, although they are the most expensive, they are very popular.
Cost Factors
Many cost factors control the price of your loft conversion.
Location in the country
London labour prices are about 10% to 20% higher than the remainder of the country so tend to control the overall cost.
Also, the distance between your house and the building contractor’s base means there is wasted travel time each day. This also affects the price.
Moreover, builders merchants delivering the materials needed to convert the loft, have delivery charges based on the distance travelled.
Weather
Time of year also governs prices. While building a loft conversion, there are always a few days when the roof is open to the elements. For this reason, most conversions take place during the summer. Unfortunately, labour prices are at a premium during these months because of the large amount of other work available.
Size of loft
For obvious reasons, if the loft has a large footprint, there will be a large amount of work to be done. And, a large amount of materials needed.
Style of conversion
This ties in with the size of the loft. The table of loft conversion costs discussed earlier clearly shows the relative estimated costs of different styles. The lower–priced renovations tend to be very basic loft conversions. While the more expensive styles involve much more complex work involving highly-skilled professionals.
Comparing Quotes Could Save Up To 33%:
Strengthening
All loft conversions need larger flooring joists inserted alongside the existing joists. But, some need RSJs to support the floor and other heavy loads. Some styles also need additional roofing timber to accommodate the change in roof profile.
Plumbing and drainage
Some loft renovations have en-suite shower rooms, toilets, and in some cases kitchen sinks. In each case, you will need hot and cold water supplies as well as wastewater and sewage drainage. This is an extra expense that other conversions might not need.
Central heating
The extra rooms need heating. The cheapest method is to to use standalone electrical heaters wired directly from the consumer unit. However, if your central heating boiler has some spare capacity, you might be able to insert extra radiators into the loft conversion. Or, you can choose wet or dry underfloor heating.
Example Cost Calculator
We have to agree that a typical loft conversion can be expensive. But, if we consider an example of a typical loft with a 30m2 footprint, we can break down the total cost (say £40,000) into chunks to see where the money goes.
- Project management, architect, plans and other fees will cost about £9,000. This will be professional fees only, with no materials involved.
- Scaffold hire will be about £4,000. This will probably be a straight fee for the approximate estimated duration of the job.
- Preparation of the site before starting the job will cost about £1,000. This could be clearing vegetation in the garden from where the scaffolding will be placed. Can also be the installation of a shed or container for safekeeping of materials.
- The roof structure will always need altering. This could be alterations as insignificant as allowing for a Velux window. Or, something as major as building a Mansard loft conversion. For this exercise, we’ll assume its around £5,000.
- Some loft conversions need RSJs to support structural alterations. The cost will vary depending on the changes to be made. But we’ll assume its about £4,000.
- After alterations to the roof, we will need additional roofing felt and tiles or slate. Assume that this costs £6,000 to install.
- An extra room needs lights and powerpoints. So, this will cost about £1000.
- Internal joinery, such as studwork for plasterboard walls, skirting boards, doors, door frames and architraves, cost about £4,000.
- A staircase is a legal requirement and will cost about £2,000 to purchase and install.
- Installing plasterboard covering for ceiling and walls. Then, plastering the surfaces will cost about £3,000.
- Finally, decorating all plastered and wood surfaces will cost about £1,000.
Comparing Quotes Could Save Up To 33%:
Planning & Compliance Expenses
House alterations as major as these might need professional input from an architect and structural engineer. Also, loft conversion plans need submitting to the local authority for Building Regulations and planning approval (if relevant).
The cost associated with these professional fees include:
| Item | Estimated cost |
|---|---|
| Local Planning (plans submission) | £172 |
| Building Control | £40 to £800 |
| Architect | £500 to £1500 |
| Surveror & Structural Engineer | Usually, work for the architect, with fees included in their final bill. |
| Party Wall Act survey | £200 to £1000 |
| Other: Bat Survey | £300 to £400 |
| Other: Asbestos Survey | £150 to £500 plus any remedial work if asbestos is present. |
Comparing Quotes Could Save Up To 33%:
Local Planning
Usually, a loft conversion won’t need planning permission as long as the changes comply with certain stipulated conditions. However, sometimes there will be times when you must apply for permission. Fees for this are usually £172 in England. But, if you are in doubt, contact your local authority for advice on fees. However, there is a Fee Calculator on the Planning Portal website that will give an approximation.
Building Control
Every loft conversion must comply with the UK Building Regulations. How much you pay for this will depend on the extent of the alterations and whether you use tradesmen who belong to the Competent Persons Register and can self certify their work. ‘Self-certification’ means that they are trusted to always do good quality work, which doesn’t need to be checked by Building Control. Check with the contractor to find out if they and their subcontractors belong to the scheme. Or, whether their quotation includes Building Control fees. Average fees for a typical loft conversion are about £700, depending on the size and type of work.
Architect Costs
Although many loft conversion specialists are capable enough to handle the project without formal plans, it’s often better to have definitive plans:
- You will receive an accurate quotation of the work specifying what tasks needs to be done.
- The plans specify sizes of structural timbers and RSJs. So you know that the loft conversion will be safe and structurally sound.
- Plans make sure that you are both ‘working from the same page’. Otherwise, it’s very easy for you to talk at cross purposes with the contractor. And, end up with a conversion different from the one you were expecting.
- You know that everything has been specified by a qualified person, independent from the contractor. This ensures that they don’t ‘cut any corners’ when purchasing materials.
- You as a customer, probably don’t know what can and can’t be done. Therefore, it is easy for an unscrupulous contractor to buy cheap, substandard materials, and convince you that it will be perfect for the job. Without an architect’s plans, you wouldn’t know any better and would accept the contractor‘s knowledge and experience.
- An architect has a structural engineer who can specify sizes and strengths of necessary components.
- If you need to liaise with the local authority, architect’s will handle this.
An architect’s fees will vary depending on how much work they do, and the size of the conversion. They will also subcontract structural work to qualified engineers and surveyors, and include their fees on the final bill. Typical architect’s fees cost between £500 and £1500.
Comparing Quotes Could Save Up To 33%:
Surveyor & Structural engineer
Surveyors specify a datum point on site from where the contractor takes all measurements. This is very important when the conversion incorporates distance from boundaries and the height of the roof, to comply with planning permission requirements.
Structural engineers take into account the extra loads on the building from various factors such as:
- The extra weight of the conversion materials and how they affect the supporting walls and existing foundations.
- Effects of prevailing winds on the profile of the roof after conversion.
- The engineer specifies dimensions and specifications of structural timbers and RSJs.
A structural engineer ensures the structure has sufficient strength to withstand the extra loads. Building Control needs the calculations to prove the structure is safe and ‘fit for purpose’. Their fees will be determined by the amount of work required and will usually be incorporated within the architect’s fees.
Party Wall Act
The Party Wall Act etc 1996 only applies if you have a terraced or semi-detached house and the loft conversion affects the party wall between your house and your neighbour’s. You will need advice from a Party Wall surveyor, which costs about £200. And, if you need an agreement drawn up, this will cost around £1000. Often, the architect will organise the survey and incorporate the report into the documentation submitted to the Planning Office.
Comparing Quotes Could Save Up To 33%:
Other
Bats are a protected species in the UK and so are their roosting spots. If you believe you have bats present in your loft, you will need a survey and a written report to apply for a licence. The local authority will then decide on whether you can start the work. A typical bat survey costs between £300 to £400.
Many homes built before the 1990s contain asbestos. And, much of this was used in the loft as pipe lagging and general insulation. If your home is older than this, it’s worthwhile having a survey to confirm one way or the other the presence of asbestos. A typical asbestos survey will cost between £150 and £500 depending on the size of your property. Plus, you will need to reserve funds for the removal and any remedial work involving asbestos. Don’t shirk on this one, as it’s a legal requirement to remove asbestos if you intend to disturb it.
UK Building Regulations
All renovation work needed to make a loft habitable must comply with the UK Building Regulations. Therefore, any loft conversion from the most basic to an extremely complex one needs the following minimum alterations to comply.
Floor reinforcement
The existing joists are only ceiling joists for the room below. So, will need strengthening or replacing with floor joists. The extent of the reinforcing will be calculated by a structural engineer based on the span and the expected load. Usually, The contractor will position larger dimension joists across loadbearing walls and next to the existing joists. In certain circumstances, you might need to replace the wooden joists altogether with RSJs (Rolled Steels Joists). Whatever changes or additions take place, they will be specified by the structural engineer. This item comes under Part A of the Building Regulations (Structural safety).
Insulation between the roof rafters
This is an important addition to the loft to make the habitable space comply with the Building Regulations. At the time of writing, the minimum U-value for a roof must be less than or equal to 0.18W/m2. This is equivalent to 270mm of fibreglass blanket, 175mm of rigid board insulation or 125mm of spray foam. Other stipulations depend on the type of roof you have. This comes under Part E (Resistance to Sound) and Part L (Conservation of Fuel and Power).
Staircase for safe and efficient access
There are various styles that you can use. But, they must all comply with Part A (Structural Safety) and Part B (Fire Safety).
A heating installation
Preferably, this will be an extension of the property’s central heating system. But, if this isn’t possible, you can install independent electrical heaters. This comes under Part L (Conservation of Fuel and power).
Electric power points and lighting
The electrical circuits should have a separate ring main and be connected to the main consumer unit. Furthermore, if you’re using electrical heating, you’ll need separate heavy–duty cables protected by a separate circuit breaker. Electrical safety comes under Part P (Electrical Safety).
Opening windows
You must have ventilation, and hopefully, natural light in a habitable room. This comes under Part F (Ventilation).
Fire doors and smoke alarms
These warn occupants and prevent the spread of fire and smoke within the home. They come under Part B (Fire Safety).
Plumbing
Some loft conversions (usually not the smaller ones) have en-suite toilet and shower facilities. These would come under Part G (Sanitation, hot water and water efficiency).
Comparing Quotes Could Save Up To 33%:
Benefits of Converting Your Loft
Many obvious advantages help promote loft conversions.
- Increased space is probably the main advantage. The conversion allows you to expand your living space, without having to increase the property’s footprint. You aren’t adding more foundations, walls or a roof, which considerably reduces the costs of a loft conversion compared to an extension.
- A loft conversion will add value to your property. It’s an extra living space, that other, similar houses might not have. On average, a loft conversion might increase your house value by up to 20%.
- Natural light into a living room is always a bonus. If you install good–sized windows into your loft conversion, you’ll have a habitable room placed above shady trees and other buildings. Thereby reducing the amount of shade.
- Although a loft conversion must comply with a long list of Building Regulations, it’s still a lot less than a typical extension.
- An average loft conversion will be much easier and less costly than moving home. Plus, you have the advantage of investing your money into your existing property to increase its value.
Comparing Quotes Could Save Up To 33%:
How Long Does a Loft Conversion Take?
A typical loft conversion involves many tradesmen and can take many weeks. This duration depends on the weather and how easy you can schedule the different professionals to be on–site when needed.
If you have the luxury of good weather and all the trades are available when needed, then the job will run very smoothly as follows.
Before starting the build
Ensure you or the project manager has submitted all the documentation. And, you have the required local authority permissions. Also, ensure the architect has finished the plans. And, all appropriate surveyors have completed their surveys.
The following timeline assumes all tasks go as planned and takes the minimum time. In our experience, this very rarely happens.
Week 1
Erect scaffolding and make sure the scaffolders provide a roof cover to protect the loft interior from wind and rain. Also, ensure all required materials are on site. During this week, the roofer will remove roof tiles and save for later.
Then, open up the loft space.
Week 2
Depending on the type of conversion, alter the roof structure. Install extra supports and RSJs as required. And, strengthen floor joists. If you intend having roof lights, install these now, otherwise build dormer frames.
Week 3
Finish all ‘exterior work’ and make the roof weatherproof. Fit the roof insulation and do first fix plumbing and electrical work. Therefore, installing cables and pipes in cavities and beneath the floor.
Week 4
Insert any windows still not in place (dormer style?). Then, lay the flooring, plasterboard walls and ceiling, and add ventilation. At this stage build and plasterboard internal dividing stud walls.
Week 5
Install staircase and any first fix joinery such as door frames and linings. If you have an en-suite toilet and shower, now is the time to install those. Skim plaster. Then, insert second fix electrics and plumbing fixtures and fittings. Follow this with second fix joinery such as doors, skirting boards and architrave.
Week 6
Complete any unfinished tasks. The scaffold can be removed at this point. If the plaster has dried enough, decorate the walls and woodwork. However, decoration might need to be postponed until a later date when the plaster is fully dry and stabilised.
Comparing Quotes Could Save Up To 33%:
Additional Extras For Your Loft
When you’re considering a loft renovation, there are always extras that you might not have originally thought about. So, make up your mind at the planning stage, what exactly you want. And, stick to it.
Adding a Bathroom
As space is at a premium in a loft conversion en-suite bathroom, it’s worthwhile forgetting about using a bath. Instead try installing a toilet, washbasin and shower or preferably even a wet room. A fully fitted wet room with toilet and basin costs between £3,000 and £8,000 depending on fittings and choice of tile.
New Staircase Replacement
Fire safety regulations stipulate that all loft conversions must have a professionally built staircase. Stairs must have a certain amount of headroom. So, follow the slope of the roof upwards as you climb the loft stairs and exit at ridge height. The cost of a typical staircase varies depending on length, height, material, and ornamentation. A typical basic staircase costs around £1200 but can go as high as £10,000 if its custom made in hardwood. Strict Building Regulations govern the manufacture of stairs. Step size, riser size, bannisters, spindles and handrails must all conform to standard sizes. Make sure these comply by having the stairs professionally designed and made.
Underfloor Heating
It’s worthwhile considering underfloor heating while you are building the loft conversion. It’ll be much easier than installing the system afterwards. Underfloor heating has advantages because it requires less heat than a traditional radiator to produce the same temperature rise in the room. Also, you aren’t using up valuable space with wall radiators. Underfloor heating costs from £300 to £900.
Moving Water Tank
Many homes have a water tank in the loft resting on a platform connected to the rafters. To build your loft conversion, you must move the tank to a more convenient location. Or, remove the tank entirely and change the type of boiler you have. If you decide to remove the old tank, this will cost between £100 to £200. To upgrade your old boiler to a combi will cost around £3,500. And, to move the tank to another location (this could be behind a wall in the loft), costs about £600.
Asbestos Removal
In homes built before the 1990s, you might find some asbestos in your loft wrapped around the water pipes as lagging or made into board as fireproofing. Before you start any alterations in your loft, have an asbestos survey done. It will cost you between £150 to £500. If you find asbestos, you must pay to remove it safely.
Truss Style Roofs
Roofs can be made using two methods, rafters or trusses. Rafters are individually cut and placed lengths of timber meeting their opposite counterpart at the ridge board. Although sometimes opposite rafters have braces holding them together, usually they don’t. Instead, they use purlins to prevent sag. And, have the rafter dimensions larger than necessary to support the roof’s load.
On the other hand, trusses are engineered as ‘A’frames with a cross brace joining the two ‘rafters’. Trusses use the absolute minimum amount of timber in their construction to reduce costs as much as possible, while still supporting the loads.
You can probably see that a truss’s cross brace will make the loft conversion very difficult, and very expensive to build. Although not impossible to achieve, the roof needs additional rafters to take the weight before the cross braces on the truss can be removed. To calculate how to alter a roof truss to allow enough room for a loft room, you’ll need a structural engineer, who will charge between £500 and £1,000. To physically strengthen the trusses will be very expensive indeed.
Comparing Quotes Could Save Up To 33%:
Loft Conversion Ideas
Loft conversions can have many uses. Some might be needed to house an ever–growing population of children, while other uses might just be for fun. Here are some examples. I expect you can think of a few more.
- Children’s bedrooms. Kids love a space all to themselves. Especially, at the top of the house and away from everyone else.
- How about a master bedroom with an en-suite toilet and shower. Adults like a large area to themselves with a panoramic view of the surroundings. It’s almost as if they have a private space away from an otherwise busy house.
- Playroom. Just think, the entire room can be dedicated to toys and play, without disturbing the rest of the house. No more picking up the kid’s toys before you can sit down. And, they don’t have to be children’s toys either. A loft conversion will make a perfect place for an artist’s studio or to house a model railway.
- An office might be a good idea. A room at the top of the house is less likely to be interrupted and is well away from the rest of the family.
- How about a loft bedroom for guests? A loft is a great place for a guest room. It’s easy to close it up when it’s not in use, and your guests can feel like they have their special place in your home when they visit.
Comparing Quotes Could Save Up To 33%:
Loft Conversion Q&A
Is It Cheaper to do a loft conversion or an extension?
Not only is it cheaper. It’s also easier and doesn’t take as long. Now, if you’re deciding between a loft conversion or an extension, don’t go any further than this list. The few points here should convince you.
- A loft conversion has to comply with a lot less Building Regulations than an extension.
- Loft extensions take just a few weeks or so to build from start to finish, whereas an extension can take much longer.
- When building an extension, excavating trenches, laying concrete foundations, and building supporting walls take up a lot of time and money. A loft conversion uses the existing foundations and walls so it’s much cheaper.
Can my neighbour stop my loft conversion?
Most of the time, your neighbours can’t prevent you from building a loft conversion. As long as you comply with the rules laid down by your local authority, all they can do is cause delays and give you a lot of stress. A good piece of advice is to stay friends with your neighbour and try to keep them on your side. You can do this by keeping them informed right from the beginning and taking on board any suggestions they might have.
How much is a loft conversion on a bungalow?
A dormer loft conversion is relatively straightforward to build in your bungalow. They tend to be cheaper than a loft conversion in a house. And, typically cost between £30,000 and £60,000 with an average of about £45,000.
Can I do a loft conversion myself?
Let me tell you now. Any size loft conversion is a major job that you shouldn’t attempt unless you are an experienced DIY addict or a carpenter. You will need a deep understanding of roofs, their structural capabilities and how they’re built. You’ll also need a plumber, electrician, roofer, plasterer and a carpenter/joiner.
As far as the local authority is concerned, they will check your work with a fine–toothed comb and expect you to know the Building Regulations inside out.
Comparing Quotes Could Save Up To 33%:
Does a loft conversion add value to your home?
Most estate agents and building societies reckon that a well–built loft conversion will increase your property value by up to 20%. So, if your home values at £200,000, you have an automatic increase of up to £40,000. Now, that’s a pretty good return on your investment.
How do you know if your attic can be converted?
If your roof is made from rafters and purlins rather than trusses, you will be able to convert the loft easily. However, if you have trusses, then it will be so expensive, you may as well build an extension instead. Trusses are designed to use as little wood as possible and are constructed in a factory. They aren’t designed to be taken apart, so don’t try.
Can a freeholder refuse a loft conversion?
Yes. If the freeholder owns the fabric or “bricks and mortar” of the property, then they can refuse to consent to your proposal. Or, they can charge you a fee for the privilege. The reasoning behind this is that usually, the freeholder is responsible for all repairs to the building, including the roof and guttering. And, these are held for the benefit of all the leaseholders within the property. Therefore, you cannot go ahead and make changes to something for which you do not own and have no responsibility.
Find Local Loft Conversion Builders
Converting or renovating your loft is one of the cheapest and most effective ways to increase the living space in your home. A well–constructed loft conversion will also add value to your property by up to 20%. But, don’t try to build one as a DIY project. It’s too complex and needs a lot of specialist knowledge.
Instead, fill out the form on this page and you’ll receive 3 to 4 quotes, offering very competitive loft conversion costs from vetted builders in your area.
Comparing Quotes Could Save Up To 33%: