We explain the true price of a hip to gable conversion, what affects the final cost, and how to budget with confidence. If you’re comparing hip to gable loft conversion costs, partial loft conversion prices or simply want to know what a hip to gable extension costs, you’ll find everything you need here.
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A typical hip to gable loft conversion costs between £30,000 and £70,000 in 2025, depending on the size of your home, the level of finish, and your location. If you’re adding extras like a dormer or an en suite bathroom, expect to be at the higher end of that range.
Below, we break down average costs, what's included, and what can drive your final quote up or down, so you can budget with confidence before starting your project.
The average cost of a hip to gable loft conversion in 2025 sits between £30,000 and £70,000, depending on the size of your loft, the quality of finish you choose, and where you live. To help you budget more accurately, the table below shows typical costs by specification level, along with the approximate price per m².
Most hip to gable lofts fall between 25 and 35m², which means a typical mid-range conversion usually costs £45,000 to £55,000. Larger detached homes or premium design upgrades can push the total above £70,000.
Homes in London and the South East often sit at the upper end of the price range due to higher labour and material costs
A hip to gable loft conversion combined with a rear dormer is one of the most effective ways to maximise floor space. It also comes with a higher price tag than a standard hip to gable because you are adding both structural work and a full-width dormer.
In 2025, the average cost ranges from £55,000 to £85,000, depending on the size of the property, the level of finish, and whether you include extras such as an en suite or bespoke storage. Premium upgrades or larger detached homes can exceed £90,000.
Below is a clear breakdown of typical costs and price per m².
A partial hip to gable loft conversion is a more affordable alternative to a full hip to gable. Instead of extending the entire side roof, only part of the hip is built up to increase usable headroom. This reduces structural work and keeps costs lower, making it a popular option for smaller lofts or properties where a full gable build isn’t required.
In 2025, the average cost ranges from £20,000 to £40,000, depending on the amount of structural alteration, loft size and internal finish.
Below is a breakdown of typical prices and cost per m².
While most hip to gable loft conversions fall within a typical price range, the final cost of your project can vary significantly depending on a few key factors. From the size of your property to where you live, here’s what drives the price up, or helps keep it under control.
The larger the footprint of your home, the more structural work, materials, and labour will be needed, which means higher costs.
Hip to gable conversions involve major structural changes. The more complex your roof design or internal layout, the more your costs can climb. Expect costs to rise if your conversion involves building a new gable wall, raising the ridge height of the roof, or installing supporting steel beams.
If a full re-roof is required, this adds significant labour and material costs compared to a partial alteration.
Read our full guide on roof lift loft conversions to get a complete understanding of altering your roof for you new loft conversion.
What you plan to do inside your new loft space plays a huge role in the final cost. A basic bedroom conversion will naturally be more affordable, while adding an en suite bathroom, built-in wardrobes, or custom joinery can quickly increase the price.
Higher-end finishes such as premium flooring, bespoke lighting, or smart home technology typically add between £5,000 and £15,000+ to your overall build, depending on the level of detail and quality you choose.
Where you live has a significant impact on the overall cost of a hip to gable loft conversion. Labour rates, material prices, and even the availability of experienced contractors can vary widely by region.
Homes in London and the South East typically attract a 10-20% premium, driven by higher demand and living costs. In contrast, properties in Northern England, Wales, and Scotland often benefit from lower build costs and more competitive pricing.
Use our loft conversion cost calculator to understand how much you'll be paying.
While many hip to gable loft conversions fall under permitted development rights, this is not always the case. If your home is in a conservation area or the design exceeds standard limits, you may need full planning permission. This can cost between £250 and £500, with additional professional fees bringing the total to between £1,000 and £2,000. Regardless of planning status, building control approval is mandatory and ensures the conversion meets structural safety, insulation, and fire regulation standards.
The ease of accessing your loft and property can significantly impact labour time and logistics, which in turn affect the cost.
Modern loft conversions must meet Part L of Building Regulations, which governs thermal performance. Upgrading insulation and meeting energy standards can add cost, especially in older homes.
The cost of a hip to gable loft conversion varies depending on the type of property you own. Each house type comes with different structural considerations, such as roof shape, ridge height, and access, which can influence both labour time and material requirements.
Below is a breakdown of estimated 2025 costs for different property types, based on standard mid-range finishes.
Bungalows often sit at the higher end of the cost range due to their wider roof spans, which typically require more materials and support. Detached homes may also require additional ridge support or internal alterations to accommodate staircase access and layout.
A mezzanine loft conversion can be achieved within a hip to gable structure, but is more suited to larger or architect-designed properties. These typically appeal to homeowners looking to create light-filled, open-plan living spaces with visual impact.
If you're working to a budget, there are smart ways to reduce the cost of your hip to gable loft conversion without compromising quality. Here are a few tried-and-tested tips:
Yes. In most cases, a hip to gable loft conversion is well worth the investment. It typically adds 15% to 25% to your property’s value, depending on the location, finish, and how the extra space is utilised (e.g., adding a bedroom with an en-suite bathroom).
According to research from Nationwide Building Society, adding a double bedroom and bathroom through a loft conversion can increase a home’s value by up to 21%. In high-demand areas like London, the return can be even higher.
While upfront costs range from £45,000 to £70,000+, the long-term return on investment (ROI) makes it one of the most valuable types of home improvement, especially for families needing more space but wanting to avoid moving costs or stamp duty.
Learn more in our how much value does a loft conversion add guide.
Under UK permitted development rights, a hip to gable loft conversion must not exceed 50 cubic meters for detached and semi-detached houses or 40 cubic meters for terraced houses.
The conversion must use materials similar in appearance to the existing home and must not extend beyond the existing roof slope facing the principal elevation or highway.
Side-facing windows must be obscure-glazed and non-opening if they are less than 1.7 meters above the floor level. For in-depth insights and detailed guidance, check out our comprehensive Permitted Development Rights Guide and unlock the full potential of your loft conversion project.
Below are some of the most common cost-related questions homeowners ask when planning a hip to gable loft conversion. From pricing breakdowns to VAT and optional upgrades, these quick answers help you budget more confidently.
A hip to gable loft conversion with a rear dormer usually costs between £55,000 and £85,000 in 2025. This higher price reflects the additional structural work required to extend the hip and build a full-width dormer. Premium finishes or an en suite can push costs above £90,000, especially in London and the South East.
Yes. A hip to gable conversion involves more structural work, as the entire side roof must be rebuilt into a full gable end. This makes it more expensive than a standard rear dormer on its own.
Yes, and it’s one of the most popular combinations for semi-detached and detached homes. A hip to gable with a rear dormer usually costs £55,000 to £85,000, depending on size and finish, and offers the most usable space of all loft types.
A partial or shell-only hip to gable conversion typically costs £20,000 to £30,000 for structural work only. This includes building up part of the hip but does not include insulation, plumbing, electrics or internal finishes. A more complete mid-range partial conversion usually sits between £28,000 and £35,000.
A shell-only hip to gable conversion is the lowest-cost option. Structural work is completed, but the interior is left unfinished. Prices typically start from £20,000 to £30,000, not including insulation, electrics, plastering or flooring.
Yes. Adding an en suite or bathroom usually increases the budget by £5,000 to £10,000+, depending on plumbing complexity, sanitaryware, and whether new drainage runs are needed.
Smaller lofts can show a higher cost per m² because fixed items, such as scaffolding, structural design, steelwork and labour setup, cost the same regardless of floor area. These fixed expenses are spread across fewer square metres, raising the per-m² figure.
The cost per m² for a hip to gable loft conversion ranges from £1,300 to £2,500, depending on the level of finish.
Most hip to gable lofts measure 25-35m², which is why typical projects fall between £45,000 and £55,000 for a mid-range finish.
Yes. Common add-ons include planning fees (if required), structural upgrades, enhanced insulation, bespoke storage, and higher-spec finishes. These can add £2,000-£5,000 to the core build.
In most cases, yes. Loft conversions are charged at 20% VAT. Some exemptions or reduced rates may apply for qualifying properties (for example, listed buildings or major energy-efficiency works). Always confirm VAT status in your builder’s quote.
