How Much Does a Loft Conversion Cost?

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Kitchen in loft with large roof windows

Converting your loft space is the perfect way to breathe new life into your home. Creating convenient and comfortable living space, providing more accessible storage, and even adding 10-25% additional market value to your home, a loft conversion is an ideal choice for many reasons. It is also a fantastic choice for those who lack the outdoor space to construct a conservatory or extension but can instead build upwards to add the extra space. With this type of home conversion remaining as popular as ever, the big question that you may be considering is, how much does it even cost?

There are a mix of factors that can have an effect on the overall cost, so considering each is important to create a clear plan when it comes to paying for your new dream loft conversion.

Table of Contents

Cost by Type of Loft

The most common denominator in determining the cost of your conversion will be the size of the space you are starting with and the type of loft conversion you hope to achieve. There are a variety of individual selections you can make through the process to increase or reduce the overall price, but let’s start by first outlining the different types you can consider. These pricing estimates are relevant to labour costs and building components included in the process.

Basic Rooflight Loft Conversion

The simplest kind of loft conversion will incorporate elements such as floor reinforcement, electrics, roof windows, insulation, a staircase, heating, and lighting as well as fire safety enforcements. With a rough measurement, this kind of roof conversion can cost between £15,000 and £25,000, dependant on the choices you make.

Dormer Loft Conversion

A dormer loft conversion involves a box shaped structure being installed into a pitched roof to increase the volume of the roof space and provide extra head height. There are a selection of types of Dormer Loft including single dormer, full width dormer, side dormer and L-shape dormer, each structured to fit different available roof spaces. This kind of conversion permits the fitting of full size windows and larger, full height furniture whilst generally creating a more open and airy room. It is a more expensive choice than the basic rooflight conversion as it involves completely rebuilding a roof pitch with all the internal work needed too. An average cost estimate for a dormer loft conversion calculates between £25,000 - £50,000 but the more labour-intensive L-Shaped alternative can reach prices of £40,000 - £75,000.

Hip-To-Gable Loft Conversion

A hip-to-gable loft conversion is designed to extend your property space by replacing the roof slope at the end of a terrace or detached house with a brick wall. This type of conversion creates additional space in your loft and is perfect for opening up more of the room. As the modifications to the roof structure are more substantial and a brick gable wall is needed rather than a stud wall, the general cost for this kind of loft conversion can sit slightly higher at anywhere between £30,000 and £60,000.

Mansard Loft Conversion

Situated at the back of the property, a mansard loft conversion alters the sloping side of your roof to a flat roof structure with the back wall sloping inwards at an angle of 72 degrees. This type of loft conversion creates maximum space for your loft, forming a more light and open area. Due to the fact that the mansard loft conversion significantly alters the whole structure of your roof and requires more extensive work than the other options, this conversion type is more expensive. This loft extension can be priced anywhere between £40,000 to £70,000 but can be pricier dependant on your home structure and individual requirements.

What Am I Using My Loft Conversion For?

When stepping into a project such as this, it is always key to consider what you will be using your loft conversion for. Loft conversions are brilliantly versatile with many used as bedrooms, home offices, children’s playrooms, living rooms and some even incorporating an ensuite into the design which is a choice that can significantly enhance the value of the conversion. It is important to think about this as for example, plumbing an entire ensuite will increase costs vs a bedroom without one. Also taking flooring for example, the purpose of your conversion will impact the type of flooring you want, whether or not underfloor heating is an option etc which all again contribute towards the end cost.

Main Factors to Consider

When building your loft conversion, there a wide number of variables that ultimately contribute to the overall end cost. Here is a list of factors that you will need to consider when calculating the price of your conversion.

  • Windows
  • Staircase
  • Insulation
  • Electrics
  • Lighting
  • Heating
  • Fire Safety Measures
  • Flooring
  • Plumbing
  • Scaffolding
  • Skip Hire
  • Building Materials
  • Decorating

Windows are key in a loft conversion to create stylish natural light in your space. Depending on the type of conversion best suited to your home, the amount of and style of windows will change, contributing a substantial amount of the cost. Velux windows for example, can range anywhere between £325 and £550 generally dependent on size, whereas dormer windows are anywhere from £150 to £300.

A factor such as stairs is also a cost that you may not immediately think of that can also add a chunk of cost to the total amount. There are a selection of styles you can choose with a fixed ladder sitting less expensive at lowest £150 and a spiral staircase leading up to costs of £1500.

Planning Permission and Building Regulations

Building regulation costs are also considerations that you will need to take with your loft conversion project. It is advised that you have complete plans drawn up for the conversion by a professional to outline the changes that need to be made to your roofing structure and create an idea of the finished product. This service will incorporate its own cost with anywhere up to £1000 sitting at a reasonably average rate.

For most loft conversion projects, you will not require planning permission as the structural changes are permitted. There can be cases however, where planning permission may need to be applied to which with widely varying costs, can go up into the low hundreds.

Your loft conversion will also require inspection to ensure it has been designed and constructed in accordance with building regulations. Plans submission and on-site inspections can ring up a price of up to £800 at the highest so it is definitely something worth considering when calculating the cost of your loft conversion.

It is possible that you may also need a party wall agreement if your work may affect neighbouring homes. This is a requirement for your neighbours to agree on the work being done and means you are liable for costs including their surveyor plus any of their home damages which may ensue in the construction process. Reliant on the agreement’s complexity this could all cost up into the thousands which is another fee to possibly consider dependant on your situation.

Though not often as considered, if you think your loft space may be inhabited by bats, you could also need a bat survey which can add up to another few hundred pounds into the calculations.

Building & Labour Costs

With finalised plans, regulations and calculations completed, you can now begin the process of construction. This is where a substantial amount of the costs come into play with a variety of jobs including project management, scaffolding, plastering, decoration, alterations to the roof structure, electrics, plumbing, roof coverings, joinery, and steelwork. Again, your calculations are dependant on the type of conversion, size of your loft and the purpose of your conversion which will be discussed individually with the team involved. However, to give a rough idea, a rooflight conversion over a timescale of 4-6 weeks could amount to up to £14,000 in general labour costs.

Extra Costs

During the planning and construction process, additional costs can also creep up for extra work, amounting to a higher end amount.

As the majority of loft conversions require construction work on your roof, you may find that your roof needs repairing or maintenance. You may need to replace some roof tiles, repair your guttering or simply some general cleaning and upkeep.

If you have a water tank in your loft, you will need to pay to move and dispose of it, even if it is no longer in use. This can potentially cost up to £600. If it is a working water tank, you may also need to install a new boiler system elsewhere.

If you are installing an ensuite or designing the loft conversion as a bathroom, you will additionally need to think about the costs of the bathroom suite plus plumbing and installation costs. This can enhance pricing significantly in comparison to a bedroom or general living area.

If your loft was the main storage space for your belongings, you will also need to think about where these items will be stored once your loft conversion is undergone. This may implement extra costs with the need to purchase additional storage solutions.

Is It Worth It?

With all costs considered, you may be wondering if all the money spent is worth it in the long run. Thankfully, studies have shown that converting your loft into a liveable space can increase the value of your home by up to 20 - 25%, meaning your conversion will benefit you right up to the potential sale of your house. Loft conversions can additionally increase the energy efficiency of your home with all the extra insulation which can in turn potentially decrease your utility bills.

Final Tips For Keeping Costs Down

  • Planning - Correctly planning out all of the details and potential costs before beginning any part of the construction process is the main way to ensure you that you can manage how much you are spending. Sticking to a strict plan from the very beginning will keep the project under control and ensure you can achieve the highest quality end result without the prices increasing unexpectedly.
  • DIY where you can – Although you may not be able to contribute in DIY style towards the full construction of your loft conversion, getting small jobs done yourself can actually knock off a fair amount of costs. For example, decorating, painting, and finishing the interior yourself can be much less costly then hiring another professional to complete the job for you.
  • Talk to the professionals – Going into a large project such as this with no knowledge and expertise can be challenging. Researching and talking to professionals and specialists that you can trust will help you gain an understanding of how to approach the different tasks in the most effective way. Professionals often also have access to trade discounts, suppliers, and other tradespeople they can recommend to help you get the best prices possible.


Converting your loft into a living space can completely transform your home. Researching, planning, and considering all of the necessary costs is vital for ensuring the highest quality results and a smooth process from start to finish. Whilst adding impressive value to your property and an exciting new space to relax to your home, loft conversions are definitely seen as worth the work and price point by many.

If you have any more questions about how much a loft conversion costs, get in touch with our award winning customer service team. They can be reached via telephone on 01295 565 565 or the live chat on our website.

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