Explore Our In-Depth Guide to Loft Conversion Prices

In 2016 a survey by the Nationwide Building Society showed that a loft conversion can increase a property’s value by up to 20%.

But how much does a loft conversion cost and how long does the work take?

Converting your loft from a cold dark storage area to a desirable and habitable living space is, in fact, one of the quickest and cheapest ways to add extra room and value to your home.

With the cost of moving house so expensive, loft conversions are an affordable way to get extra floor space.

How much this project costs will depend on the existing roof structure and any planning constraints but use our guide below to give you a rough idea of how much this type of work should cost.

Today a quick search on Google shows loft conversion companies claiming the work can be done for as little as £18,000.

But, how realistic is this price?

Loft conversion prices screenshot

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Is My Loft Suitable for Converting?

On this page, we’ll show you how much a loft conversion costs but our prices assume your loft has enough headroom for the conversion.

If your loft doesn’t have enough headroom then the roof will need to be raised or in some cases, the floor below lowered. The cost for these types of conversion is not covered by our price guide. For more complex loft conversions such as these, you will almost certainly need planning permission and a customised price.

For more complex loft conversions such as these, you will almost certainly need planning permission and a customised price.

Measure the Headroom Yourself

Tape measureIf you haven’t done so already, measure the space between the bottom of the ridge timber in the centre of the roof and the top of the ceiling joist.

The bare minimum for a conversion constructed with a dormer should be 2.3 metres and ideally more.

For a loft without dormers, just roof windows, you really need 2.5 metres as a minimum.

The Homeowners Alliance has more detailed information about lofts that are suitable for conversion.

Check out their site here.

What is the Difference Between Planning Permission and Building Regulations?

Planning permission typically covers how the work will look externally and how it affects the property and any neighbouring dwellings.

Building regulations cover things like fire regulations, safety, ventilation, electrics and plumbing etc.

Is Building Regulation Approval Required?

Yes, all aspects of the build must meet current building regulations and be signed off at various stages throughout the work. For example, the insulation must be approved before the plasterboards are installed.

The UK government’s Planning Portal is the best place to find more information about regulations for loft conversions.

Check out the Planning Portal here.

Is Planning Permission Required?

Planning permission is not normally required. However, permission is required where you extend or alter the roof space and it exceeds specified limits and conditions. Source: www.planningportal.co.uk

Loft plans
About 75% of all loft conversions are covered by “permitted development” rules which allow for work without going down the arduous planning permission route.

For example; a typical semi-detached house outside of a conservation area and with plans for a rear dormer and front aspect roof window would not require permission.

However, a front aspect roof dormer, increasing the roof height beyond original build height, listed buildings or construction in a conservation area would require planning permission.

Framed or Truss Roof

Framed roof structures were used on most properties until the mid 1960’s and are generally more suitable for loft conversions.

Trusses are typically used with thinner timbers and while the prefabrication method results in a faster installation time, they often require additional support during a loft conversion.

Additional support is usually achieved by installing RSJs (rolled steel joints).

Both types of roof structure can be converted but extra supports take more time to install and will add to the overall cost of the build.

Typical Loft Conversion Cost

A typical loft conversion could be described as:

  • front aspect roof windows
  • rear aspect window or dormer construction
  • side facing windows (if any) to be obscured glass
  • headroom within the existing structure
  • does not overhang original wall construction and walls ideally ~200mm back from roof eaves
  • no balconies or verandas
  • less than 40 cubic metres for a terraced house and 50 cubic metres for semi-detached or detached dwellings
  • the building is not a flat or maisonette
  • the materials used will be in keeping with the original structure

*the cubic metre allowance must include any existing loft conversions.

Below are our suggested loft conversion prices, we updated these in 2021 and based them on prices given to us by several loft conversion companies.

Single room, roof windows but no dormer£32000.00
Double room, roof windows but no dormer£35000.00
Double room, shower en suite, roof windows and one dormer£43000.00
Get a Custom Price HereGet a Custom Price Here

Our Guide Price Excludes…

The prices you see displayed in the table above include all labour costs but do not include the cost of a bath, shower, basin carpets or blinds.

Expect the Loft Cost to Increase if…

Houses with slate roofs tend to cost more to convert than ones with concrete tiles.

Townhouses require extra scaffold at additional cost.

How much work needs to be done to the original building, for example; constructing new partition walls, completely redesigning the layout of the floor below or relocating water tanks to make room for a staircase would add extra cost.

The condition of the existing wiring will need to be inspected and potential changes made such as a new consumer unit.

Our experience of home improvement projects is limited to the south-east of the United Kingdom, we believe that prices in central London would be higher, while houses located in regions further north would be somewhat cheaper.

Where Does Your Money Go?

More Detail

Below is a more detailed list covering all aspects of a loft conversion:

  • Architect’s fees
  • Structural engineer fees
  • Planning permission fees
  • Building control fees
  • Party wall fees
  • Scaffolding
  • Timber work including floorboards
  • Insulation
  • Plasterboards
  • Dormer construction
  • Roofing felt, leadwork, tiles and vents
  • Windows and roof windows
  • Staircase construction and installation
  • Electrics
  • Plumbing for hot and cold water as well as waste removal
  • En suite items and installation
  • Wall tiles and flooring
  • Doors and trims
  • Painting and sealants
  • Blinds and curtains

Have You Received Prices? Let Us Know!

This is your chance to let us and other visitors to this site know what prices you’ve received from tradespeople for a loft conversion.

Paul Foley (Liverpool)double bedroom and ensuite shower, loo and sink (2020)£28500
P Jones (Hants)Basic loft conversion with 2 large roof velux windows, no en-suite, just the double room and staircase. (2020)£25,000
Jane Clark (Hertfordshire)1 bedroom with 2 Velux windows, no ensuite or dormer. Truss roof. Additional stud work to open plan living room downstairs to create protected stairway.
Price quoted excludes fees, planning permission (required), building regs, decoration and carpeting. Also had to pay for change to combi boiler (cost excluded). (2019)
Simone Reilly (Richmond)My husband and I converted the loft of our previous house in Richmond. We had an extra bedroom with en suite and some additional work downstairs which included moving a water tank. (2017)£33000
Paul Heseltine (Kettering)I recently purchased a house where the third bedroom is little more than a cupboard, the best price I have been so far for a loft conversion with an en suite is £31,000 (2017)£31,000
John (Kensington)Double bedroom with shower room, we need to raise the height of the existing roof so planning permission is required. Partial re-slating of the roof is also needed. We've received two prices so far that are far higher than the figures suggested on your site, most likely due to the extra work we need. (2017)£64,000 and £59,000
Michael Eddington (N Wales)1 bed loft convert with 4 roof windows. (2017)£27,000 inc VAT

You can add your own prices and details via the form on this page.

How Much Do Others Think a Loft Conversion Will Cost?

There are several other websites that claim to know the cost of a loft conversion.

We recommend visiting these:

Which? is a well-known brand in the United Kingdom and they offer consumer advice and services. On their website, they have a handy guide to loft conversion prices (subscription is required but it’s heavily discounted for the first month and easy to cancel).

Simply Loft lists some of the most popular types of loft conversion and a realistic price. They’re definitely worth checking out here.

Prime Location also list prices based on the size of the loft. Explore their guide here.

The Two Most Common Types of Loft Conversion

  1. a loft constructed without dormers and only roof windows within the constraints of the existing building.
  2. a loft with a rear aspect dormer and front aspect roof windows.

Any type of loft conversion project outside the scope of these two options may cost considerably more than the prices we have suggested.

These sites are worth exploring if you need more information about loft styles and options:

Up Another Level’s guide to loft conversion styles

Harvey Norman Architect’s in-depth guide to loft conversions is a great read too

Our Beginners Guide to Loft Conversions is also a great read

How Long Does the Work Take?

This depends on the size of the project but 6-9 weeks is a good estimate.

Don’t forget that different trades, such as roofers, electricians, plumbers and plasterers will need to come at different times and there’s almost always a slight delay between each part of the project.

Our week-by-week guide goes into more detail.

Week 1 – Scaffold erected, materials delivered to site and roof opening made.

Week 2 – Change the structure of the roof and add extra supports if required, construct the dormer and begin internal work.

Week 3 – Complete dormer construction and most of the external work including insulation. Begin plumbing and electrical work.

Week 4 – Install windows, vents, floor and plaster boarding.

Week 5 to 7 – Bathroom installation, staircase installation, finish electrics and plumbing, door hanging, trims and skirting.

Week 8 to 9 – Decoration and finishing off work. Lower scaffold.

Get Ideas and Inspiration

As regular visitors to our site will attest to, we are huge fans of Pinterest.

If you are in need of some inspiration for your loft or just looking at ideas and options, go check out the many thousands of images you’ll find on Pinterest.

You could start with these 25+ loft conversion ideas on Pinterest.

Get a Firm Quote

We have done our best to research the cost of a loft conversion but our prices are guides and nothing more.

To get a firm, fixed quote in writing, tap the link below to see how we can help:
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We suggest you explore the following websites for official guidance regarding loft conversions:

Planning Portal - loft conversions

Government website - permitted developments

Slough council guide to loft conversions (pdf)

We feel these websites are worth exploring if you are planning a loft conversion:

The loft converting mini guide

An in depth guide to loft conversions by an architect

We feel that this price is not realistic for a complete loft conversion but could apply to the structural aspect of a small conversion.

Some homeowners use a professional firm to carry out the structural work and then complete the remaining work either themselves or by arranging for other tradespeople to do it.

We can only conclude that a price of £18000 is for this type of conversion.

Planning permission is not normally required. However, permission is required where you extend or alter the roof space and it exceeds specified limits and conditions.
Yes, absolutely, especially if you have enough space for an en suite as well as a good sized room. In fact, a loft conversion is the cheapest, easiest and quickest way to gain extra floor space and increase the value of the property.

This guide was written by and was last updated in April 2021.

Don’t forget; we have price guides for hundreds of home improvement projects.

Explore our full list of detailed price guides here.

Author - Danny Woodley
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