Find out about the average cost of loft conversion, the benefits and building regulations and stop wondering about how much does a loft conversion cost.

As the need for more space becomes bigger and bigger and you are thinking of extending your property rather than moving to a new one, a loft conversion becomes one of the available option.
loft conversion cost


Benefits of Loft Conversion

1. Increase the value of your home. The increase can be 15-20 % according to the Federation of Master Builders and Nationwide Building Society.

2. Lower cost, greater value. A loft conversion costs less than a full extension or moving to another property.

3. Easy to carry out. Converting a loft is quite simple and it will take only up to two weeks, when it will be finished.

4. Many uses: 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.

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: ItIt 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 GSanitation, 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. This is structurally possible, however, there is the high expense as well as getting the required planning permission. In the case where the whole roof has to be removed, the house will have to be protected from the elements during construction by a covered scaffold structure.

Solution 2: In the Room Below Decrease the Ceiling Height

Some older homes have a ceiling height of 3m or higher in some rooms, therefore there is the option of decreasing the ceiling below if the roof space height is restricted, providing it will still permit a minimum of 2.4m. All appropriate ceilings will require removal, creating a mess.

This approach requires a plate to be bolted to the wall with rawbolts or shield anchors, from which the new floor joist will be hung. A proper tie between the roof structure and the dwarf wall created is required 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 plasterwork 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.

Average Cost of Loft Conversion In The UK

The cost of loft conversion will vary depending on a range of factors, including:

  • 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. ‘Standard’ loft conversions consist of a basic conversion including two roof windows, ‘deluxe’ loft conversions include two roof windows, two dormer windows and an en suite bathroom.

Loft Conversion Price Guide

20m² standard20m² deluxe30m² standard30m² super
Northern Ireland£8,750£19,550£9,750£20,550
Northern England£11,850£26,550£13,050£27,900
East Anglia£11,350£25,300£12,550£27,000
South East England£12,250£27,350£13,600£28,700
South West England£10,850£24,800£12,350£26,050

The cost of loft conversion London is slightly more due to increased labour and material prices in the city. To get an idea of the prices, check out the table below. Again, the figures are rounded and should be used only as a general guide.

Loft Conversion Cost London

20m²  standard20m² deluxe30m² standard30m² deluxe
Inner London£13,400£30,000£15,000£31,500
Outer London£12,700£28,200£14,100£29,600

DIY Loft Conversion Cost

Certain loft conversions are possible to implement as a DIY projects. We recommend, that you hire a professional 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!

DIY Loft Materials  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

The average cost of a DIY loft conversion will be from £10,000 – £40,000 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!

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.

How Much Does 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 cost

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 type  Cost
An average attic conversion£20,000 – £30,000
A shell conversion£16,000
A small velux conversion without plumbing£20,000

Looking to convert your loft? We can  help!

Guide to Bungalow Loft Conversion Costs

Costs of bungalow loft conversion will be lower than conversion for the house. It depends a lot on the size of your project and for what kind of purposes you are planning the loft conversion. As a general rule can be said, that bungalow loft conversions will be used as commonly as extra bedrooms. This kind of projects are quite simple and inexpensive to implement.

We can estimate that bungalow loft conversion are from 30% -40% cheaper than the conversion for the house. There are same regulations to make bungalow loft conversion than bigger ones. Maybe there is one specific question, which you have to consider especially. It is staircases to the loft. Usually there is not a lot of space for staircases and stairs have to be safety. This can mean the increasing the cost for your project and require a good planning.

Bungalow loft conversion compared to the conversion for the house is 30-40 % cheaper

Hip to Gable Loft Conversion Cost

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. 


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.

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 fulfil 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 metres. 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.

To help you estimate the cost of a hip-to-gable loft conversion with did some research and gathered estimates from several loft conversion companies in the UK.

Loft conversion company Cost£30,000 – £35,000£32,000£35,000

Mansard Loft Conversion Cost

The average cost for a Mansard loft conversion is about  £48,000 -£55, 500.

mansard loft conversion cost

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!

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.

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.

We contacted several loft conversion specialists and companies and requested information about the cost of the mansard loft conversion, to help you get a better ideas of how much is a mansard loft conversion.

Loft Conversion Company  Cost£35,000£33,000 – £34,000£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 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 the loft conversion bur 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!

Comments are closed.

The best way to find a tradesman
Fast, Easy and Free!
  • Tell us about your home improvement project
  • Get up to 4 calls from local tradesmen
  • Compare your quotes
  • Hire the tradesman of your choice
Have You Found What Were Looking For?
We are here to help!

Everyday jobs. Home improvement. Home maangement. Sorted
Find a Tradesman Today
  • Submit your job
  • Receive free estimates from tradesmen
  • Compare your quotes
  • Hire the tradesman of your choice