Find out about loft conversion, the benefits, building regulations and stop wondering about how much does a loft conversion cost.
As the need for more space increases, instead of moving to a new property, a loft conversion is one of the most straightforward ways of extending your property.
On this page
- Benefits of Loft Conversion
- How To Plan For A Loft Conversion
- How Long Does A Loft Conversion Take?
- Is My Loft Suitable for Conversion?
- Traditional Framed Roof
- Do I Need Planning Permission for a Loft Conversion?
- The Party Wall Act and Loft Conversions
- Loft Conversion Building Regulations
- Is There a Way To Increase The Head Height of My Loft?
- New Ceiling Joists
- Room in Roof Loft Conversion
- Dormer Loft Extension
- What Loft Insulation Do I Need?
- How Much Does A Loft Conversion Cost
- DIY Loft Conversion
- Attic Conversion Cost
- Bungalow Loft Conversion
- Hip to Gable Loft Conversion
- Mansard Loft Conversion
- How To Find A Good Loft Conversion Company
Benefits of Loft Conversion
Increase the value of your home
The increase can be between 15% – 20 % according to the Federation of Master Builders and Nationwide Building Society and market research conducted by the Guardian. According to Nationwide, you property’s value can increase on average by approximately £37,000.
Lower cost, greater value
A loft conversion costs less than a full extension or moving to another property. Once the conversion is built, you can start making money by renting the new space. You do not have to wait to sell the house, to see a return on your investment.
Easy to carry out
Converting a loft is quite simple and it will take only up to two weeks, when it will be finished. Not to mention that several loft conversions do not even require planning permission.
Avoid the cost of moving
Home-movers according to Telegraph will have to pay on average £10,000 to move into a new property (selling your property and buying a new one). By converting your loft you can avoid all these unnecessary expenses, stay in the same job, keep the children in the same school and avoid looking for a new parking space.
More natural light
A loft conversion will add more natural light to your property with the right windows. With more natural coming in your house you will reduce your energy consumption and also improve your productivity and overall health.
It´s a very versatile option for your needs; for an extra bedroom or bathroom, for a lounge or additional living area, for an office or a gym or a home cinema. Your imagination is the only limit.
How To Plan For A Loft Conversion
An extensive and detailed plan will help things to run smoothly and keep the loft conversion cost low (as you will have already allocated funds in a preliminary budget and been made aware of any problems that need fixing beforehand). There are several things to consider when planning your loft conversion, including the following:
- Loft Stability – if the loft is any higher (from the bottom joists to the top apex) than 2.4m, then you might need the ceilings lowered to ensure structural integrity.
- Escape Routes – these need to be accessible via an open stairway or large window or skylight.
- Energy Conservation – loft conversions should be installed with the most up-to-date insulation materials, to trap heat in the home during the winter and prevent wasted energy usage.
- Ventilation – loft conversions also need adequate ventilation to provide clean air to the new room and prevent a build-up of mould or rising damp (which can cost considerably more than standard windows and fans to remove!)
How Long Does A Loft Conversion Take?
Loft conversions usually take between 4 to 7 weeks to complete. The first two weeks all the work is being done from outside or within the roof space. On weeks 3 and 4 the floor joists and the loft floor and insulation are completed, while the ventilation and stud walls are still a work in progress. On weeks 5 and 6 the rest of the house is opened to the loft as the staircase is now fully fitted and the stairway is made good by installing the handrails and banisters. The last week any plastering, carpentry work is completed and all the plumbing is installed and tested successfully.
Is My Loft Suitable for Conversion?
Several homeowners consult either an architect or have long meetings with building contractors before they go ahead. However, the most important thing to consult your local authority with regards to any planning issues. Before you do any of all this, consider the following aspects to get an idea if it is possible to convert your loft.
Loft Conversion Assessment
They key features that will determine if your roof space is suitable for a loft conversion are:
- Head height
- Type of structure
A roof inspection is necessary by a roofing professional to reveal the roof skeleton and its physical dimensions.
- The usable part of the roof should be greater than 2.2m.
- Ask the architect or designer your hired to illustrate clearly how much headroom there will be across the floor in the finished space.
- The standing space is not always clearly conveyed on plans, so many people are disappointed after the conversion has been completed.
- Habitable rooms have no limitation when it comes to the ceiling height.
- The headroom standard for stairs is 2m but it can be easily decreased by 100 – 200 mms on the edge of a stair when necessary.
A sealed hot water system, will replace the water tank and plumbing, as there will no roof space left anymore.
When it comes to replacing your boiler with a combi boiler, consider using unvented hot water cylinders instead. They make a far better choice but they require more space and budget in order to build a cupboard-sized room.
The pitch angle plays a great importance when it comes to floor area. The higher the pitch angle, the more loft space there will be, especially if you are redesigning the roof or using dormers.
What type of roof do you have? Is it a traditional framed type or a cut rafter and purlin roof.
Traditional Framed Roof
- Before 1960s
- The rafters and ceiling joists are cut and put together on site, together with the supporting timbers.
- Framed roofs are more strong and stable, so they are more suitable for attic conversions.
- Another benefit is that you can easily open up space by strengthening the rafters and adding supports.
- After 1960s
- The most popular roof types used were factory-made roof trusses.
- They use thinner timbers (which are cheaper).
- Good structural integrity by the use of braced diagonal timbers.
- House roof can be erected and felted in a day.
- Difficult to open up space without additional structural input.
- The insertion of steel beams is normally required to support the rafter sections and the new floor joists.
- It is advisable to seek the advice of professional roofers and not to attempt to DIY to save money.
- Consider using laminate or vinyl for flooring to save money.
Do I Need Planning Permission for a Loft Conversion?
Loft conversions do not usually require planning permission as they tend to be considered as Permitted Developments (PD). However, If you are changing the footprint of the property (extending or changing the roof space) your design will need to comply with certain rules and regulations. In this case you will need to apply for planning permission. You can find more information on the Government’s planning website.
The Party Wall Act and Loft Conversions
In addition to planning permission, if your house shares a wall with a neighbouring property under the Party Wall Act 1996 you need to inform your neighbours in writing that work is taking place; they have the right to contest this if they want to. To make sure your loft conversion goes smoothly, it’s best to talk to your neighbours beforehand.
Loft Conversion Building Regulations
Before you start your loft conversion project you have take into consideration any building regulations related to conversions, as all home improvement projects in the UK need to comply with the following standards for design, construction and alterations:
1. Part A – Structural safety: It involves you to make sure that the loft wall, floors and joists are sturdy enough and there is sufficient headroom in the loft.
2. Part B – Fire safety: It involves that you make sure that there is an escape route in case of fire and that the right smoke alarms are installed.
3. Part E – Resistance to sound: It involves that you make sure that there is an adequate sound proofing in your loft conversion.
4. Part F – Ventilation: It involves that you make sure that there are enough air vents and windows to adequately ventilate the converted space.
5. Part L – Conservation of fuel and power: It involves that you make sure that the converted space is property insulated to conserve energy.
6. Part P – Electrical safety: It involves that you make sure that all electrics in your loft has been installed by a qualified electrician.
7. Part G – Sanitation, hot water safety and water efficiency: It involves that you make sure that all plumbing has been installed correctly and safely, if you plan to install an en suite bathroom as part of your loft conversion.
Is There a Way To Increase The Head Height of My Loft?
Did the initial inspection of the roof space show that the head height was under 2.2m? If so, you have two options, both of them costly and you will need help from a professional.
Solution 1: Raise the Roof
A portion or even the entire roof would have to be removed and then rebuilt to get the necessary height and structure. Even though, this is structurally possible, the cost is high and it is also difficult to acquire a planning permission.
In the case that the whole roof has to be removed, the whole house has to be protected during the construction.
Solution 2: Decrease the Ceiling Height In the Room Below
In several older homes where the ceiling height is 3m or higher in some rooms, there is the option of lowering the ceiling to a height to minimum of 2.4m.
This method requires a plate to be bolted to the wall with rawbolts or shield anchors, from which the new floor joist will be hung. Proper bonding between the roof structure and the dwarf wall is needed to stop the roof from spreading.
Any DIY participation should be confined to demolition supervision and cleaning.
New Ceiling Joists
The current ceiling joists are probably inadequate to bear a conversion floor, therefore supplementary joists would be needed to meet the Building Regulations. The dimensions and grade have to be determined by the structural engineer, who will consider the span and the separation distance of the load applied.
Load-bearing walls support the new joists, which are usually elevated just above the current ceiling plaster work by applying spacers under the end of the joists. There has to be enough space to stop any deflection in the new floor joist from contacting the ceiling plaster underneath. The new joists are laid next to the current joists. Thicker wood is used to bridge the openings over doors and windows so that no stress is added to the current opening lintel.
Rolled steel joists (RSJ) are usually stipulated for load distribution, and in certain installations are employed to support the new joist ends. Where head height is restricted, then wider joists, more closely positioned, could be stipulated.
Room in Roof Loft Conversion
The cost for a basic ‘room in roof’ loft conversion starts from £15,000 and is probably one of the cheapest solutions. This usually involves:
- Reinforcing the floor
- A couple of skylights
- Additional insulation
- A loft staircase
- Heating installation
- Electrics and lighting
- Fire doors and smoke alarms
Dormer Loft Extension
Dormer loft extensions are another option that does not require to make big changes to the roofing structure. This structural extension projects vertically from the plane of the the sloping roof. With the addition of dormer windows the usable floor-space increases and transforms the attic to a naturally bathed space.The additional floorspace can be used to add more head height which gives more flexibility when it comes to placing the stairs.
The average dormer loft extension cost comes to £20,000+. However, the average cost of a double ensuite room is between £35,000–£45,000.
What Loft Insulation Do I Need?
One of the most vital elements to consider when planning and carrying out a loft conversion is how to properly insulate and also and what type of insulation to use, as this can have a major impact on the available space when the conversion is finished. When reconditioning/remodeling an attic or loft space, it is necessarily to comply with the local Building Regulations/Standards.
In England, according to the building regulations the minimum U-value of a roof must be 0.18W/m2 or lower. For flat ceilings the minimum U-value must be 0.16 W/m²·K. In the case of a complete re-roofing the roof must be insulated to a minimum U-value of 0.15 W/m²·K. For new roofing constructions the U-value is 0.15 W/m²·K and for refurbishments 0.18 W/m²·K; these values apply to both flat and pitched roofing structures.
Note: O.18W/m2 is equal to a 270mm thick layer of fibre or wool insulating material, roughly 175mm of rigid board insulation or about 125mm of high-efficiency spray foam.
Types of loft insulation available
There are many types of loft insulation available, made from different insulating materials. It is best to get a loft survey done so that a professional installer can advise you on what type of insulation you need and what the cost will be. Loft insulation surveys are often provided free of charge by roof insulation companies. Here are the main types of roof insulation:
Blanket/Quilt insulation – This type of insulation comes in readymade sheets made of usually manmade materials like glass or rock wool fibre. Mineral wool is the most common type of insulation used in the UK. Blanket insulation is good for large accessible loft spaces as it fits neatly between the joists and is the most common type used in lofts.
Sheet/Board insulation – Ideal for loft conversions and covering the sloping sides of roofs, this type of insulation is easy to disguise by covering with plasterboard, leaving a neat finish. Sheet insulation is usually made from polystyrene material and comes in rigid flat sheets, which can be cut to size.
Blown insulation – Normally made from mineral wool and cellulose material, this type of insulation is blown into specific areas of the roof. If you have hard to reach spaces in your loft this is a good option and is quick and easy to install by hiring a professional.
Loose fit insulation – This type of insulation comes in bags and is made of material like cork granules or recycled newspaper. It simply needs to be scattered in the roof space and is most suitable either as a top up to existing insulation or in very hard to reach places.
How Much Does A Loft Conversion Cost
A loft conversion costs on average between £10,000 – £32,000, depending on the type of property. However, you could end up paying up to £60,000 for a particularly large extension. Loft conversion prices are generally affected by the following factors:
- Your location in the country.
- The size of the loft.
- Whether the loft requires any strengthening work.
- If you are looking to build a roof or dormer windows.
- Whether you want to have a bathroom.
- If you need to install central heating.
One of the biggest factors affecting the cost of loft conversion is location. To illustrate this, below we have created a table with the average prices for loft conversion in the UK. The loft conversion prices listed below are estimates only.
Loft Conversion Prices UK
The basic loft conversion cost in the United Kingdom for a 20m² loft ranges from £8,750 to £10,850. For a deluxe loft conversion expect to pay from £19,950 to £24,800. For a 30m² basic conversion the price comes between £9,750 – £12,350. For 30m² expect to pay from £20,550 to £26,050.
|Location||20m² standard||20m² deluxe||30m² standard||30m² standard|
|South East England||£12,250||£27,350||£13,600||£28,700|
|South West England||£10,850||£24,800||£12,350||£26,050|
Cost of Loft Conversion in London
The cost of loft convesion in London starts from £12,700 for 20m² for a standard loft conversion and £28,200 for a deluxe loft conversion. The prices are slightly higher in inner London due to increased labor and material prices in the city, so expect to pay on £1,000- £1,200 pounds more.
|20m² standard||20m² deluxe||30m² standard||30m² deluxe|
DIY Loft Conversion
The average cost of a DIY loft conversion cost comes around to £30,000 depending on the specifications, materials and desired size. You can reduce the cost significantly by doing proper research online, asking around and comparing prices. Track your budget during your project and make necessary changes to your plan, if necessary. And remember, save money for any unexpected expenses!
Certain loft conversions are possible to implement as a DIY projects. We recommend, that you hire a professional loft conversion company for more complicated loft conversions such like mansard, hip-to-gable or dormer conversions.
When you are having a basic loft conversion as a DIY project, you have to make, good plans, budget your project carefully and purchase all the necessary materials before getting started. It is very important for you to know, how much your loft conversion will cost. You need to allocate enough time to this phase of the project but it will save you money.
Here are some basic needs for fittings, materials, appliances and fixtures you might need to invest in your project. We hope, that this list will help you to plan your project and to estimate the total budget for your project!
|Loft Conversion Materials Breakdown||Cost|
|Structural beams, joists and masonry: including flooring, doors and a new staircase||£1,500 – £5,000|
|Electrical wiring and lightning: including plug sockets, bulbs and fixtures|
|Insulation: including plasterboard and boarding||£500 – £800|
|New bathroom: including all pipe-work, basins, shower-fittings, tiling and furniture||£4,500 – £6,000|
|Windows: including two small or one large velux-style skylights, double glazed||£800 – £2,000|
|A new combi-boiler, if necessary||£600 – £3,000|
|Interior design materials: including paint, wallpaper, storage cupboards and new furniture||£800 – £30,000|
Note: if you don`t feel competent and proficient enough to handle the building and construction work, it might be wiser to hire a professional conversion specialist for your project. Don´t underestimate the time and energy that you need to invest in the project.
Attic Conversion Cost
The average cost for an attic conversion is £20,000 – £30,000 . A small attic conversion in rural England will cost about £16,000, while for the same job in London the cost nearly doubles. The average cost for a small attic conversion is around £27,000.
Attic conversion costs vary depending on your requirements and in which part of the UK you live. For instance, a shell conversion will cost less than a full mansard job with bathroom fittings and new plumbing.
Attic Conversion Prices
|Attic conversion type||Cost|
|An average attic conversion||£20,000 – £30,000|
|A shell conversion||£16,000|
|A small velux conversion without plumbing||£20,000|
Bungalow Loft Conversion
Bungalow loft conversion cost is 30%-40% cheaper than house conversion. It depends a lot on the size of your project and for what kind of purposes you are planning the loft conversion. Typically a bungalow loft conversions is used for extra bedrooms. This kind of projects are quite simple and inexpensive to implement. The cost however, increases if there is not enough space for a staircase to be safe enough.
Hip to Gable Loft Conversion
The average cost of a hip to gable loft conversion will be around £33,000. However, depending your requirements, your location and the quality of the materials, the cost can reach £38,000.
When to use
If your house has a hipped roof with sloping sides, than a standard loft conversion is not the best solution for you, as a hipped roof is usually difficult to convert. With hipped roofs i) there is not much space, ii) there is little headroom under the diagonally sloping ceilings iii) and they cannot support the beams and joists, as it is required in traditional conversions.
Benefits of Hip-to-gable Loft Conversion
This is where a hip-to-gable loft conversion comes in as you can maintain the structural and aesthetic integrity of your home and create this extra space you need. This type of loft conversion extends your house on the sloping side and a vertical wall is built to replace the sloping roof at the end, with the same height at the ridge, filling in the space in between.
The newly created space can fulfill any function you need mostly and can make your life easier. Popular choices are usually a master bedroom with an ensuite, a second living room, and an office or a gym space. You can even accommodate a fully integrated staircase with a hip-to-gable loft conversion.
One thing that you need to remember before you start planning your hip-to-gable loft conversion is that the height of the space needs to be at least 2.2 meters. Estimate carefully how much money you need to spend and try to involve a conversion specialist right from the beginning to help you do the planning. It might cost you more but this type of loft conversion is little bit more challenging and expensive than the standard loft conversion.
Hip-to-gable Loft Conversion Prices
To help you estimate the hip-to-gable loft conversion cost with did some research and gathered estimates from several loft conversion companies in the UK.
|Loft conversion company||Cost|
|Loft-conversion-cost.co.uk||£30,000 – £35,000|
Mansard Loft Conversion
The mansard loft conversion is named after the 17th Century French architect Francois Mansard and is created usually at the the rear side of the property, extending across the entire plan of a roof. This type of conversion has a flat roof with the back sloping inwards at 72 degrees. The windows are usually build into small dormers. The average Mansard loft conversion cost is about £45,000-£55,500.
With proper planning and design specifications you will get the extra space you always desired, while maintaining the structural integrity of the property. This is what a Mansard loft conversion is suitable for!
When To Use
Mansard loft conversions are suitable for both detached and semi-detached houses and terraced properties, chalets and bungalows too. This makes the mansard loft conversion a very popular method among loft conversions.
Mansard Loft Conversion Prices
We contacted several loft conversion specialists and companies and requested information about the average mansard loft conversion cost, to help you get a better ideas of how much is a mansard loft conversion.
|Loft Conversion Company||Cost|
|Theloftking.co.uk||£33,000 – £34,000|
|Loft-conversion-cost.co.uk||£34,000 – £45,000|
How To Find A Good Loft Conversion Company
When you are starting to plan your loft conversion project and you are not sure about how much does a loft conversion cost or whether you need to apply for a planning permission for your loft conversion, consult your local council, a loft conversion company or an architect. On the top of that you can also apply online to receive free loft conversion quotes from our nationwide database of tradesmen and also try other networks such as RatedPeople, MyBuilder, Checkatrade etc.
Here are several tips to help you find a qualified conversion specialist or company
- Stay local choosing the company.
- Ask your insurance company for recommendations.
- Check credentials.
- Check the contractor`s license and insurance.
- Get it in writing.
- Don`t pay for labor up front.
- Ask for copies of receipts.
A loft conversion project is relatively easy way to increase the space and value of your property. It does not require very long time to complete and the ROI is also great. When the project is completed you will have plenty of new space to use as an extra bedroom, an additional living room, a playroom or an additional bathroom etc.
You can attempt to DIY to reduce the loft conversion cost but if you do not feel confident or luck the skills it is better to hire a contractor for your project….. But remember! Consult always with a conversion specialist in any case. We wish a good luck for you and enjoy your extra space!