Hip to Gable Loft Conversions in London

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A hip to gable loft conversion replaces the sloping side of a hipped roof with a vertical gable wall, extending the ridge to create more usable floor space and headroom. It’s particularly suited to the 1930s and inter-war semi-detached houses found throughout South London.

Clapham Construction Service has more than 20 years of experience designing and building loft conversions across London. We can assess your existing roof, advise whether a hip to gable is the right option and manage the project from initial design through to completion.

Interested in Hip to Gable Loft Conversions? Contact Us Today

What is a Hip to Gable Loft Conversion?

A hipped roof slopes down at the side of the property as well as towards the front and rear. While this creates a distinctive roof shape, the additional slope can significantly restrict the width of the loft.

A hip to gable conversion removes the sloping side and replaces it with a vertical wall. The existing ridge is extended across to meet this new gable, creating full-height space where the roof previously sloped towards the floor.

For many London homes, this can transform a narrow attic into enough space for a comfortable bedroom, bathroom or combination of the two.

Structural Implications of Hip to Gable Loft Conversions

Hip to gable conversions involve significant structural work. The existing hip is carefully removed, a new gable is constructed and the enlarged roof is supported with appropriate steelwork and roof timbers. Structural calculations are therefore an essential part of the design.

Read more about the structural requirements of a loft conversion.

loft extension

Which Properties Suit a Hip to Gable Conversion?

Hip to gable conversions are most suitable for properties where the hipped side of the roof is restricting usable space.

Semi-Detached Houses

A hip to gable loft conversion on a semi-detached house is one of the most common applications.

Many 1930s and inter-war semis have substantial roof space hidden behind the hip. Replacing this slope with a gable can extend usable headroom almost across the full width of the property.

One consideration is the appearance of the wider semi-detached pair. These properties were often designed symmetrically, so converting one hip while the neighbouring property remains unchanged can create an unbalanced roofline. Local planning policies and the character of the street therefore need to be assessed carefully.

Where a hip to gable is unsuitable, a rear or side dormer loft conversion may provide an alternative.

Find out more about semi-detached loft conversions.

End of Terrace and Detached Houses

End of terrace properties with hipped roofs can also be excellent candidates. Because there is no matching property beyond the hipped end, changing the roof to a gable can sometimes be easier to integrate into the surrounding roofline.

Detached properties offer even greater flexibility, particularly where the house has hips at both ends.

Bungalows

A hip to gable can make a significant difference to a bungalow, where a large roof footprint is often restricted by slopes on several sides. Altering the roof can help turn previously impractical attic space into bedrooms and living accommodation.

Learn more about our bungalow loft conversions.

Hip to Gable Loft Conversion With a Rear Dormer

One of the most effective options for London properties is a hip to gable loft conversion with a rear dormer.

The two alterations solve different problems. The hip to gable increases the width of the loft, while a rear dormer extends the usable full-height space towards the back of the property.

Together, they can make much more of the loft footprint usable.

This can provide enough room for a large bedroom and en suite or, depending on the size of the property, multiple rooms. Areas beneath the remaining eaves can then be used for fitted storage.

The combination requires more structural work than either alteration individually. The extended ridge, dormer structure and new floor all need appropriate support, which is why structural calculations should be completed before construction begins.

A rear dormer also creates opportunities for larger windows or French doors. A Juliet balcony is a popular choice because it introduces plenty of natural light without requiring a projecting balcony platform.

Hip to Gable or Dormer Loft Conversion?

A hip to gable and a dormer address different limitations.

A dormer loft conversion increases headroom by extending part of the roof, but on a hipped property it still has to work within the width left by the side slope.

A hip to gable increases that width but does not remove the slope at the rear.

For this reason, the two are frequently combined. Where planning constraints make a gable inappropriate, a rear dormer with a side dormer may provide an alternative. Where the existing roof already provides sufficient space, a simpler rooflight conversion could be considered.

See our guide to the different types of loft conversion to compare the options.

Planning Permission for a Hip to Gable Loft Conversion

Some hip to gable loft conversions can be completed under permitted development rights, but the property, location and previous alterations all need to be considered.

Permitted Development Volume Limits

Permitted development normally allows up to 40 cubic metres of additional roof space for terraced houses and 50 cubic metres for semi-detached and detached houses.

Previous enlargements to the original roof count towards this allowance. If an earlier owner added a dormer, for example, the volume created may reduce the amount available for a future conversion.

This is particularly important with a hip to gable and rear dormer loft conversion, as the combined extensions can use a substantial proportion of the available allowance.

Read more about permitted development for loft conversions.

The Eaves Set-Back Rule

Roof enlargements under permitted development are normally required to sit at least 0.2 metres back from the original eaves, measured along the roof plane.

However, hip to gable enlargements are specifically excluded from this requirement. This means the new gable can extend to the eaves line, even though a rear dormer constructed alongside it will generally still need to comply with the relevant set-back rule.

Conservation Areas

Permitted development rights for roof extensions are restricted on designated land, including conservation areas.

This is particularly relevant in South London, where parts of Clapham, Battersea, Dulwich, Brixton and Streatham are within conservation areas. Individual streets may also be affected by Article 4 directions or local design policies.

We assess the planning position before recommending a design so you understand what is achievable before progressing with detailed drawings.

Read our guide to loft conversions in conservation areas.

loft extension -Terraced House

How Much Does a Hip to Gable Loft Conversion Cost?

The cost of a hip to gable loft conversion in London depends on the size and structure of the roof, the steelwork required, whether a rear dormer is included and the final specification.

As an indicative guide for London in 2026:

  • Hip to gable conversion: approximately £45,000 to £60,000
  • Hip to gable with rear dormer: approximately £58,000 to £78,000
  • Larger conversion with en suite and higher specification: £80,000+

Restricted access, trussed roofs, extensive structural work and specialist conservation area requirements can all affect the final price.

For a tailored estimate, use our loft conversion price calculator or read our guide to average loft conversion costs.

How Long Does a Hip to Gable Conversion Take?

A straightforward hip to gable conversion will typically take around eight to ten weeks on site.

A larger project incorporating a rear dormer and en suite may take approximately 10 to 14 weeks.

Before construction begins, time also needs to be allowed for architectural design, structural calculations, planning where required and party wall procedures for attached properties.

Hip to gable loft conversion with rear dormer

Hip to Gable Loft Conversions Across South London

Hip to gable conversions are particularly suited to areas developed extensively during the inter-war period, where semi-detached properties with hipped roofs are commonplace.

We provide hip to gable loft conversions across Streatham, Beckenham, Bromley, Croydon, Sutton, Wimbledon and Dulwich, as well as Thornton Heath, Chislehurst, West Wickham and surrounding areas.

Closer to our base, we work throughout Clapham, Balham, Tooting, Battersea and Wandsworth.

Why Choose Clapham Construction?

We have been designing and building London loft conversions for more than 20 years and have extensive experience with the structural and planning considerations involved in hip to gable projects.

Every project begins with an assessment of the existing roof, available headroom, surrounding street and the space you want to create.

Our service includes fixed prices agreed before construction, directly employed teams, structural and architectural design, planning and Building Regulations support, independent inspections, £10 million insurance cover and a 10-year warranty.

skylight illustration in loft conversion

Frequently Asked Questions

Not always. Some projects qualify as permitted development, subject to the relevant conditions and volume limits. Planning permission may be required in conservation areas, where permitted development rights have been removed or where the proposed enlargement exceeds the available allowance.

Yes. It is one of the most popular combinations for hipped London properties. The gable increases the width of the loft while the rear dormer increases full-height space towards the back.

It can. Semi-detached properties were often designed as symmetrical pairs, so altering only one hip changes the original roofline. The surrounding street and local planning guidance therefore need to be considered.

Many can, but suitability depends on the existing roof structure, available ridge height, staircase position and planning constraints. We assess these factors during the initial survey.

Most straightforward projects take around eight to ten weeks on site. A hip to gable with a substantial rear dormer and en suite may take approximately 10 to 14 weeks.

Have your say…

Testimonials

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Andy Brown profile picture
Andy Brown
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From the initial meeting to the final finishing touch, Paul, Dangis and their team were great! We knew exactly what to expect each week, we had lots of photos and drone videos of work happening when we couldn’t see. They were full of advice and suggestions when we couldn’t visualise the end result. They left our home as clean and as tidy as they possibly could (we were living in the house as they were working around us). We are really pleased with the end result and with the building experience! Great time, fantastic work ethic and brilliant result!
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Rebecca Barrett profile picture
Rebecca Barrett
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We can’t thank Paul, Dangis, and the team, enough for their hard work on our house. The house is everything we had imagined and more. We increased our scope multiple times throughout the process, and the team helped us seamlessly, and were always there to answer questions and support our plans. We only have good things to say about Clapham Construction, and will definitely be recommending them to all our friends and family. Thanks again!
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Helen Stevens profile picture
Helen Stevens
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I cannot speak highly enough of Clapham Construction. Paul and Dangis were a dream to work with from start to finish. Everything was communicated so well and they provided honest, transparent and clear advice throughout; I felt supported and guided through all the decisions and they helped me make more bespoke decisions such as our windows and floor which weren’t necessarily easy! Everyone who came to work on the loft was excellent and it has all been completed to a high standard. The loft is beautiful and we just can’t believe how much space we have and how well done everything is. I would (and have!) recommend to anyone! Thank you Paul and Dangis - and we will be coming straight back to you for the next project!
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Georgia Beales
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We’ve had our dormer loft conversion for coming up to three years now and haven’t had any major issues in this time. Any minor snagging issues have been dealt with quickly by Clapham. The whole process from start to finish was seamless. All the builders were very friendly and considerate too. Will continue to recommend this company to anyone who needs a loft done and will not hesitate to use again in the future. Thank you!
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Danilo Rico profile picture
Danilo Rico
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Clapham construction service was extremely professional, the project was finished before the plan and we are so happy with our new space. Problems were resolved quickly and efficiently throughout the process. This was one of our best investment that not only added value to our property but also a significant improve of our quality of life.
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Joel Prime profile picture
Joel Prime
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I had a loft conversion completed by Clapham Construction Service earlier this year and couldn't be happier with the results. Paul and Dangis were on site every day and kept me fully informed throughout the entire process. Their communication, professionalism, and attention to detail were outstanding. I felt completely confident in their work from start to finish. Highly recommended for anyone looking for reliable and high-quality building services.
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Jane Ansell profile picture
Jane Ansell
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We recently completed a double mansard loft conversion with Clapham Construction Service, and were very happy with the whole design and build process from start to finish. Paul and Dangis were great to work with, providing clear communication and always being available to answer questions or discuss options. Their team are also excellent, with all the trades doing a great job, very professional and respectful of the rest of our house. Inevitably with a build project there were a couple of issues that cropped up along the way, but CCS were excellent at helping resolve them. We are delighted with the final loft and the extra space, and have already recommended them to others!
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Jamie Garratt profile picture
Jamie Garratt
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We have just completed a loft conversion with Clapham Construction and it was great! We are so pleased with the new loft we have in our house, but the process of working with CC was really good. They were easy to engage with from the outset, the price was competitive and the actual construction was quick and efficient. Obviously it was a major building project with all the mess and decisions you’d expect, but it was made a lot easier and less stressful working with Paul, Dangis and the team. They completed the project on time and on budget and we enjoyed working with them - that is more than almost anyone we know can say about similar projects! We’d definitely recommend them.
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Christina Ansong
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We had an exceptional experience with Clapham Construction for our loft conversion. Paul, Dangis, and the whole team were fantastic from start to finish. They transformed our attic into two beautiful loft rooms and a bathroom, exceeding our expectations with their attention to detail. The entire project was completed at an impressive speed without compromising quality. The team showed great care throughout, ensuring everything was done to the highest standard. Their service was professional, friendly, and stress-free. We’re absolutely thrilled with the results and would highly recommend Clapham Construction!
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Ayan Sengupta
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We have recently used Clapham Construction Services for loft conversion to add a bedroom and a bath in the house. We are very happy with the end-to-end experience with Paul, Dangis and the entire CCS team for high quality work done in quick time and with a very collaborative approach. Our overall project went into some unexpected blockers, but Paul and Dangis patiently helped us to resolve all the matters, kept us updated with timely communication and have been very flexible to guide us. They brought in a fantastic team to complete the work fast and in a cost-efficient manner. We will recommend CCS any day as a trusted team for home transformation projects.

Book Your Free Hip to Gable Survey

If you have a hipped roof in South London and want to understand its potential, book a free, no-obligation consultation.

We will assess your existing roof, discuss the space you want to create and advise whether a hip to gable, rear dormer or combination of the two is the most suitable option.

Call 0203 950 7957 or request your free survey online.

Request Your Free Loft Conversion Survey

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