Loft conversions are one of the most popular forms of extension in the UK. When ground floor space is at a premium, or when Planning Permission likely won’t permit other types of extensions, there’s another choice: extend upwards and make use of otherwise wasted loft space.
Like any extension, loft conversions are subject to a wide range of rules and regulations concerning structural integrity and safety. However, successive UK governments have worked to alleviate the complexity of planning and building regulations. Despite this, many are still confused as to what they can and can’t do with their property.
Today, it’s easier to build effective loft conversions than ever - if you know how.
This guide will teach you everything you need to know about loft conversions so you can get the ball rolling and unlock new living space and value for your home.
Here’s our ultimate guide to loft conversions.
Thinking about a loft conversion? You’ve probably pondered over the benefits for some time already. The main advantages of loft conversions are that they create new liveable space in your property without moving or extending onto the garden.
If you need space but don’t want to move, then loft conversions really are the perfect home investment.
If you are planning on moving relatively soon, loft conversions have the potential to vastly increase the sales price of your property, representing some of the best ROI you can achieve in today’s economic climate.
Here are 5 key benefits of loft conversions:
As mentioned, adding new space to the property is the most obvious benefit of a loft conversion.
Depending on the house, your loft might easily be big enough for a large en-suite room, or even a bedroom with a study or small sitting room. Some can even be converted into multiple rooms with partition walls.
The average loft space for 3-bed or 4-bed semis in the UK is around 20m2 to 30m2, but some are much larger, exceeding 40m2.
For comparison, the average living room in the UK is
around 13 to 14m2. Not all of this loft space is directly usable, as you have to account for the sloping sides.
Even so, most 3-bed or 4-bed semis have a large loft, and even older Victorian terraces usually have space for at least one small to medium-sized room. In most houses, all that extra loft space is almost totally unused and is probably full of old and forgotten dusty boxes, and maybe a Christmas tree.
Lofts are appealing living spaces. They’re private and well-separated from the rest of the house and many have superb views.
Dormer windows provide panoramic views which can bypass buildings at a lower level. A great view adds considerable value in itself, especially in built-up areas. The view can even be enhanced with a balcony or veranda.
Extending into the garden isn’t always ideal and may involve obtaining Planning Permission. Contrastingly, loft conversions are more likely to fall under Permitted Development Rights, which we’ll elaborate on shortly.
Gardens are highly sought after in today’s property market, so it’s worth preserving that space if possible. After all, once you extend into the garden, you can’t change your mind. Moreover, many houses don't even have gardens to extend onto, despite having available loft space.
We’ll elaborate on this below, but loft conversions are exceptionally value-efficient and can boost a home’s value by some 20%.
In built-up areas, loft conversions are probably one of the best investments you can make for your home. Not only are you adding another room to your home, but you’re also moving from one property bracket to another by adding another bedroom.
Providing that loft conversions are well-insulated with quality and preferably A+ rated double glazed windows, they tend to be energy-efficient and don’t require much heating outside of winter.
Natural light will help warm them up, saving on energy and electricity bills. Lofts make excellent working and living spaces in built-up areas where other rooms receive comparatively less natural light.
Whilst the benefits of loft conversions are clear, not all properties are suitable for loft conversions. Or at least, not all properties are suitable for straightforward loft conversions.
Here are 5 questions to ask yourself if you’re considering a loft conversion:
Permitted Development Rights apply to every local area in England and Wales, enabling property owners to modify their house without Planning Permission. But, when Planning Permission is required, plans are open to local interpretation that varies from authority to authority.
For example, the Planning Authority’s tolerance to loft conversions will differ for a detached period home in a village location than in a modern row of semi-detached houses in a built-up area.
Architects, surveyors and structural engineers will explain your options regarding Permitted Development and Planning Permission. The general trend across the UK is to allow development where possible. Extending, in general, has become easier in recent years.
The greatest consideration for any loft conversion is space. A conversion-worthy loft needs two things: sufficient volume and sufficient height.
Loft converters and architects generally agree that a minimum height of 2.4m is required to make the conversion worthwhile.
But what if the loft is massive in volume, but just a bit too low? Well, there are solutions for when the loft is ideally sized regarding its volume, but the overall height isn’t quite there. We’ll cover these shortly.
The stairs are a make or break for many loft conversions. You can’t skimp out with some form of a ladder or other thin and rickety staircases as that would never pass a building inspection.
If space is limited, staircases are often built where cupboards are, or it might be possible to relocate the boiler and place the staircase in the airing cupboard.
Sometimes, a redesign of the upper floor is needed to accommodate the staircase. It’s a solvable problem, even for smaller 3-bed semi-detached houses, but you’ll have to factor in the cost of reconfiguring your second floor.
Since loft conversions effectively add a third floor to your home, they’re subject to stringent rules regarding fire safety. In the event of a fire, escaping from the third floor is dangerous, which necessitates other escape routes or fire safety measures.
Firstly, various structural materials will need to be upgraded; the walls, floors, doors, and loft stairs will all need to provide 20 or 30 minutes of fire resistance. It may also be necessary to fit fireproof materials under the stairs and in other parts of the second storey.
Additionally, depending on your designs, you might need to construct a ‘protected escape route’. Some plans might require sprinklers or other enhanced fire safety measures. We’re going to take an in-depth look at Building Regulations shortly.
Most homes can accommodate a reasonably straightforward loft conversion, except period homes, older listed buildings or homes built before the 1930s or so. Homes built between the 1930s and 1960s have traditional roofs, which actually make some parts of a loft conversion simpler to build.
Homes built after the 1960s have stronger, trussed roofs, which take more work to alter, though this isn’t a major issue these days.
Your surveyor and architect will advise if your home needs structural reinforcement to withstand the additional weight of a loft conversion. The ceiling joists normally require reinforcement.
The Planning Portal states that loft conversions require a minimum height of 2.2m. Most companies prefer around 2.4m of height as a rule.
There are two potential solutions when ceiling height is at a premium:
1: Raise the roof: Raising the roof is sometimes not as complex as it seems. By literally extending the roof upwards slightly, it’s possible to unlock more vertical space. This can be a good option when there’s plenty of floor space, but just not quite enough height to convert. Since raising the roof affects the roof's structure, Planning Permission will usually be required.
2: Lower the floors: It may seem far-fetched, but it is possible to fit entirely new floor joists, lowering the floor in the process. This isn’t a simple job, but it may be appropriate in some situations. For example, if the loft conversion only covers a small portion of the top floor, lowering the floor might not be as disruptive as you might think.
Extensions have long been the best way to add value to any home, with single-room extensions displaying a return on investment of around 71% and an average profit-at-sale of around £17,000, according to Zopa. Other studies have found similar results, with loft conversions boosting home value by 15% to 25% across the UK, sometimes higher in London and other cities.
Loft conversions specifically can boost a home’s value by some 20%, according to a Nationwide study
cited by Chancellors.
The UK house price stood at £231,185 in January 2020 - 20% represents an average increase in value of around £46,000.
The ONS has an interactive tool to assist homeowners in estimating how much value an extension can add to their house.
In some parts of the country, extensions are worth considerably more:
There are 3 common types of loft conversion; Dormers, Mansards and Velux/roof light, and 1 less common type; the hip-to-gable.
Most homes with a loft are convertible using one of these 4 types of loft conversions.
These are by far the simplest types of loft conversion, and they’re also the cheapest and quickest to build. By fitting a Velux or roof light window into a lift and converting it into a bedroom/living space, Velux conversions require minimal external work to the roof.
Velux loft conversions are only suitable for large loft spaces with deep, gently sloping, or boxy roofs.
Probably the most popular loft conversion in the UK, Dormer loft conversions add new windows that protrude from the existing roof, adding space in the process. Standard vertical windows tend to be larger and more practical than rooflight windows.
Dormers can be fitted singly, for smaller lofts, or in pairs for larger lofts. It may also be possible to connect two Dormers at 90-degree angles in what's known as an L-shaped Dormer.
Your options depend on the shape of your roof - most 3-bed or 4-bed semis usually built after around the 1960s have hip or gable roofs, whereas larger or older houses might have intersecting T-shaped roofs or less common skillion and lean-to or hip and valley roofs.
Whilst Party Wall Agreements are not necessarily required for Dormer extensions, they may sometimes require Planning Permission for large L-shaped or double Dormers.
Though they often look similar to Dormer loft conversions, Mansard conversions modify the external wall to slope gently back towards the house, often at a 72-degree angle.
Whilst Dormers form a box shape that protrudes from the house, Mansards build new external walls across the edge of the new extension to unlock more space, also rounding off the boxy shape of the Dormer. Mansards are often preferable where a longer loft conversion is required across the long edge of the home and typically extend away from the rear of the property.
Mansard conversions are complex and are usually more expensive and time-consuming than Dormers.
Hip-to-gable conversions only apply to properties with a hip roof. By hip-to-gable, this loft conversion literally converts a hip roof (which slants across 4 sides), to a gable roof (which has just two slants).
Hip-to-gable conversions build a new external wall to unlock space from an unnecessary slanted roof by converting the inward-slanting end or side of the roof. In some situations, this option avoids party wall issues too. Hip roofs are more common on larger buildings with wide ground floors. Only end terraces can have hip roofs, and they’re uncommon on modern semis too.
The best option for you depends on your spatial requirements and existing loft space.
Velux/Rooflight - Cheapest option. | Dormer - Most popular option. | Mansard - More expensive option. | Hip-to-Gable - More expensive option. | |
---|---|---|---|---|
Mid Terrace | Suitable for terraced houses with large, deep lofts. Almost never requires Planning Permission. | Popular choice for mid terraces. Easy way to add an extra room. Single Dormers rarely require Planning Permission. | Popular choice for mid terraces. Easy way to add an extra room. Usually requires Planning Permission due to extensive roof. | Not applicable to mid-terraced houses. |
End Terrace | Suitable for end-terraced houses with large, deep lofts. Almost never requires Planning Permission. | Yes, but space at the front and rear might be more limited on the end terrace. Rarely requires Planning Permission. | Yes, but space at the front and rear might be more limited on the end terrace. Usually requires Planning Permission due to extensive roof works. | Excellent choice for end terraces where one side of the roof is a hip roof convertible into a gable roof. Usually requires Planning Permission due to extensive roof works. |
Semi-Detached House | A good budget choice for semi-d loft conversions. Probably not a great use of space compared to Dormers, though. Rarely requires Planning Permission. | Probably the most popular combination of loft conversion in the UK. Rarely requires Planning Permission (size dependent). | Popular choice for converting the rear-facing side of semi-ds. Usually requires Planning Permission due to extensive roof works. | Great choice for semi-detached houses with hip roofs. Can be combined with Dormers or even Mansards. Usually requires Planning Permission due to extensive roof works. |
Detached House | A good budget choice for detached loft conversions. Probably not a great use of space compared to Dormers, though. Rarely requires Planning Permission. | L-shaped or double Dormers are an excellent choice for detached houses. Often require Planning Permission due to size. | Often used to create long loft conversions over the longest side of a detached roof. Usually requires Planning Permission due to extensive roof works. | Great choice for detached houses with hip roofs. Can be combined with Dormers or even Mansards. Usually requires Planning Permission due to extensive roof works. |
The UK government has been trying to encourage homeowners to extend their homes for some time, relaxing the rules in the process.
As such, Planning Permission isn’t the headache that it once was, but that does depend on where you are in the country and your plans.
Certain extensions don’t require any form of Planning Permission - these fall under what is known as Permitted Development Rights (PDRs).
PDRs allow homeowners to make certain modifications to their properties without seeking Planning Permission. However, you must still seek consent from the Local Authority in the form of
Prior Approval. Even if your project easily falls under PDRs, the plans must be given the green light by the Local Authority and Building Control, though this is usually a quick process providing that your plans and drawings are in good order.
Loft conversions are one such modification that are subject to PDRs, provided certain conditions are met. A loft conversion, by law, is
"the enlargement of a dwellinghouse consisting of an addition or alteration to its roof".
For your home to qualify for PDRs, it needs to fulfil the following basic criteria:
Specific conditions apply to buildings built on Article 2(3) designated land, which includes:
If your home is in any of the above areas, it doesn't necessarily mean that you'll need Planning Permission. What it does mean is that contacting the local Planning Authority is absolutely essential. Planning involves a degree of local interpretation, and your local authority will likely have specific guidance for your area. In all likelihood, most houses built on designated land will be entitled to some form of loft conversion under PDRs.
Finally, if your home is a Listed Building, you must obtain
Listed Building Consent. Failing to do so before starting work is a criminal offence.
Then you'll likely be able to build a loft conversion without Planning Permission, subject to the following limits:
Visualising how these rules apply to your own property isn’t easy. The architectural and design consultation process will help establish what you can and can’t do under PDRs.
Even if your loft conversion does need Planning Permission, the process really isn’t as tedious as it once was, so long as you provide all the necessary drawings, detail, and background for the project.
Lawful Development Certificates are obtainable from the Planning Authority for a small fee. They declare that your intended development is lawful to go ahead and is highly encouraged (or required) by many contractors.
LDCs are also extremely useful when selling the house, as they certify that the conversion was done legally.
If your project falls under PDRs, there's another piece of ‘red tape’ to cut.
Party Walls are shared walls that divide your home from your neighbour’s home (called Adjoining Owners). All terraces and most semi-detached houses will have at least one party wall, whereas flats will have multiple. Party Walls are controlled by a piece of legislation called the
Party Wall Act.
A loft conversion will likely involve the Party Wall Act if:
In any of these situations, you'll need to serve your neighbour a (preferably professionally drafted) Party Wall Notice. Your neighbour will have 14 days to agree to your plans or object. If they object, you'll need to appoint a Party Wall Surveyor to provide an objective assessment, who will either approve your plans and provide you with a Party Wall Award, or decline them.
If the surveyor provides you with the award, then there’s little your neighbour can do to stop you from working on the Party Wall (but bear in mind that they can appeal).
Another crucial pre-construction consideration are Building Regulations.
Building Regulations are a legally enforceable framework for building safety. The rules differ in England, Scotland, Wales and Northern Ireland. Since a loft conversion forms a ‘liveable space’, they're subject o Building Regulations that ensure the structural safety and safe use of space for living in.
In England, there are two main parts to Building Regulations, part A and part B, as well as 14 other groups of specifications that span everything from electrical safety to ventilation, insulation, energy efficiency and more.
Many aspects of building regs pertain to the structure and spec of the loft conversion. Here are the main considerations for an average loft conversion project:
Fire safety is one of the trickiest elements of building a loft conversion. Loft converters, builders and architects have an in-depth knowledge of the rules, and most modern plans and designs are built to be compliant in every respect.
The costs of loft conversions vary depending on the size of the loft, the desired design/loft conversion type, location within the UK, the staircase and any necessary relocation of the boiler.
Also, building a simple bedroom, sitting room or study without a toilet or bathroom is much cheaper than an en-suite.
Here are the main cost factors:
Some average costs for different types of loft conversions in the UK are below. These prices are just a guideline of what an average project will cost. The price will generally be lower in Wales and the north of the UK, and higher in the south and London.
As you'll see, Velux loft conversions are by far the cheapest option as they don’t require any external roofing works and few structural modifications, except fitting the window and possibly moving or removing some beams.
Dormers are usually cheaper than Mansard and hip-to-gable conversions since they require fewer works to the roof and structure.
Average Loft Conversion Prices | Velux | Dormer | Mansard | Hip-to-Gable |
---|---|---|---|---|
Terraced/Semi-d: 20m2 floor space or 1 room | £10,000 to £22,000 (with one window) | £25,000 - £42,000 (with one Dormer) | £28,000 - £48,000 (with one window) | £28,000 - £48,000 (with one window) |
Semi-d: 30m2 floor space or 1 room | £20,000 - £26,000 (with one window) | £30,000 - £50,000 (with one Dormer) | £35,000 - £55,000 (with one window) | £35,000 - £58,000 (with one window) |
Large Semi/Detached: 48m2 or 1 to 2 rooms | £24,000 - £38,000 (with two windows) | £40,000 - £65,000 (with two Dormers) | £45,000 - £68,000 (with two windows) | £40,000 - £70,000 (with two windows) |
Detached: 64m2, or 2 rooms | £30,000 - £60,000 (with 2+ windows) | £45,000 - £90,000 (with two Dormers) | £50,000 - £95,000 (with two windows) | £50,000 - £95,000 (with two windows) |
Project Planning | |
---|---|
Architectural fees, survey, consultation and project management | £1500 to £3000 |
Lawful Development Certificate | £100 to £250, depending on the council |
Planning Permission | Currently £206 |
Building Inspections and Approval | £500 to £1000 |
Building Works | |
---|---|
Scaffolding | £3000 to £5000 |
Internal preparation to the walls and floors | £2000 to £3500 |
Installing a Dormer, Mansard or hip-to-gable | £5,000 to £10,000 |
Installing a Velux or roof light window | £1,000 to £3,000 |
Joinery, walls and staircase | £6000 to £8000 |
Strengthening the floor and steelwork to reinforce structure | £5000 to £8000 |
Plastering | £3000 to £5000 |
Electrics | £1,000 to £1,500 |
Plumbing | £2,000 to £3,000 |
Decoration and interior design | £2,000 to £5,000 |
VAT (20%) | Around £8,000 |
Total | £45,000 to £60,000+ (for an average project) |
Extra Costs | |
---|---|
En-suite | £3000 to £6000 |
Moving boiler | £1,000 to £5,000 |
Underfloor heating | £800 to £2,000 |
Bat Survey (if applicable) | Around £300 |
The average construction time for most loft conversions is approximately 4 to 8 weeks. You should factor in an additional 4 to 12 weeks for architectural drawings, surveys, consultations and project planning, as well as Planning Permission, surveys and Party Wall Agreements.
Planning your loft conversion requires conducting surveys, which Fast Plans provides as part of our drawings service. This will help you work out what you can and can’t do with your space and whether you’ll need Planning Permission, a Party Wall Agreement or other surveys, like a Bat Survey.
Then, your chosen architect or drawings service will draw up initial plans for your loft conversion. This might take 1 to 2 weeks. Once you give your plans the green light, you’ll need to submit them to the Local Authority and Building Control for approval.
Lawful Development Certificates are then obtained. If you require Planning Permission, submitting full plans and detailed drawings will expedite the process. Fast Plans will submit your plans to local authorities on your behalf.
Your drawings and plans will also guide your search for contractors. Fast Plans provides full specifications and projected costings, which will help you gain an accurate and competitive quote.
The loft is cleared, and any cold water tanks are removed. Scaffolding will secure the exterior of the building and prepare the site for construction works. Electrical wiring and any existing plumbing will be assessed to ensure that construction works don't cause any damage.
The construction phase varies depending on the size and scope of the project, as well as access and any extra procedures required, such as installing a bathroom, partition walls, moving or reinstalling the boiler, etc.
From start to finish, it’s wise to budget around 6 months from the minute you get the ball rolling to the minute a Completion Certificate is issued, and this is sparing any setbacks or delays.
In addition to obtaining permission from authorities obtaining a Party Wall Award from a troublesome neighbour is one of the most significant delays. The larger and more complex the project is, the longer it'll take, especially when Listed Building consent or a full structural survey is required.
To carry out a loft conversion, you'll need to obtain certain compliant drawings to submit to both local authorities and contractors. These will need to be of an accurate and professional standard - if they're incomplete, inaccurate or of otherwise poor quality, you'll not be able to get your project off the ground.
It’s imperative to obtain plans from an architect, structural engineer or professional drawings service. Fast Plans offers a
streamlined loft conversion planning and drawings
service that provides you with:
Loft conversions can add significant value to your home and rate as one of the most popular extension types in the UK. By converting your disused loft into a liveable space, you’re adding an extra room to your house without the need to move or extend outwards onto the garden.
Fast Plans
is a loft conversion and home extension planning, design and drawings service that will help you get your ideas off the ground. We provide a streamlined, professional service that doesn’t sacrifice attention to detail.
If submitting plans to local authorities for Building Regulation approval seems like a major hassle, then don’t worry, we’ll handle it for you.
Our team of professional engineers, architects and design and construction professionals work together to produce the accurate, compliant and effective drawings you need to make your loft conversion dreams a reality.
Fast Plans offers our
design and planning packages with unlimited revisions and no hidden charges.
Get in contact today to find out how we can help you.
Here’s an FAQ of common questions regarding the design process and options of loft conversions:
Some level of soundproofing is necessary for Building Regulations if you have neighbours that share Party Walls. Mineral fibre quilts are often laid in the floor for insulation and soundproofing purposes.
Proper ventilation is necessary for Building Regulations. Rooms will need sufficient opening windows. There are separate, more intensive rules for toilets and bathrooms.
Most people choose to install new radiators in the loft conversion, but the existing central heating system may need to be upgraded or even replaced in the case of conventional gravity fed systems. Electric radiators are a popular option, as is underfloor heating. Underfloor heating is an inexpensive and efficient way to heat a loft conversion that avoids placing extra strain on the central heating system (in the case of electric systems).
Windows vary hugely in price, with cutting-edge A++ rated double glazed or triple-glazed windows costing well into the thousands. Installing good-quality, well-insulated A+ rated double glazed windows is highly advisable.
Sufficient insulation is required for Building Regulations. Wool-type insulation is the cheapest but also the thickest. Polyfoams are a newer option that's suitable for thinner insulation cavities.
Yes, but this will incur additional costs. Installing a bathroom also increases cold and hot water demands, leading to additional strain on the home’s central heating system. It may need upgrading if the room is going to be used often.
It’s highly likely that the joists will need to be reinforced or replaced entirely. This depends on the house's design, but it’s standard practice to make structural changes to the weight-bearing ceiling joists.
It doesn't matter how large or small your project is, or how early in the planning process you are. We can help.
With our vast experience, we deliver both a refreshingly honest approach and great value for money; after all, when it comes to projects as crucial as these, you want to get it right the first time! Our team of experienced and highly qualified architects and designers can bring your home improvement dreams to life.
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