A hip to gable loft conversion is a popular way to transform your unused roof space into a spacious, liveable room, most commonly seen on semi-detached and end-of-terrace houses with a sloping side roof.
The process involves extending the "hipped" side of the roof vertically to create a full-height gable wall. This structural change increases both headroom and floor space, making it ideal for a new bedroom, office, or en suite. Many homeowners also choose to add a rear dormer to the cost of a hip to gable loft conversion to maximise space and light.
In this guide, we’ll explain exactly how hip to gable conversions work, which homes are suitable, and what to expect in terms of design, planning rules, and timelines.
Hip to gable loft conversions are ideal for homes with a hipped roof, where the roof slopes down on three or more sides. By building up the sloped side to form a vertical gable wall, you create more headroom and usable floor space. H
ere are the most common types of hip to gable conversions, and the kinds of properties they suit best:
A standard hip to gable loft conversion involves extending the sloping side of your roof vertically to form a straight gable wall. This simple structural change increases both head height and floor space, making the loft far more usable.
It’s a popular choice for detached, semi-detached, and end-of-terrace homes, as it blends neatly with the existing roofline while offering a practical, spacious result.
This variation combines the hip to gable extension with a rear-facing dormer,a box-shaped structure added to the back of the roof. The dormer provides even more internal space and allows for larger rooms or an en suite bathroom, thanks to the improved ceiling height and natural light.
It’s especially suited to semi-detached and detached properties where homeowners want to maximise every inch of their loft space.
Additional dormers can be added to increase space, light, or meet design requirements:
The suitability of a hip to gable conversion depends on your roof shape, property type, and available space. Here's a quick breakdown:
Hip to gable loft conversions are best suited to detached, semi-detached, and end-of-terrace homes with hipped roofs. Adding a rear dormer alongside the gable extension is one of the most effective ways to increase headroom, create spacious rooms, and let in more light.
If your home is mid-terraced or a bungalow without a hipped roof, you may want to explore alternatives such as a dormer loft conversions, Velux loft conversions, or a mansard loft conversion.
A hip to gable loft conversion typically takes 6 to 8 weeks. This timeframe can vary based on factors such as the project's size and complexity, the existing structure's condition, and any unforeseen issues that arise during construction. Here’s a summary of the timescale of a hip to gable conversion:
When planning a hip to gable roof extension, understanding volume limits is key to staying within permitted development rules and avoiding costly planning permission delays. For most semi-detached and terraced homes, the extension volume must not exceed 50 cubic metres, while detached properties have a higher allowance of up to 70 cubic metres.
If your loft conversion falls under permitted development, it must stay within specific volume limits, 50 cubic metres for semi-detached or terraced homes, and 70 cubic metres for detached properties.
To estimate the added volume of your hip to gable extension, you can use a simple formula:
Volume = (Length × Width × Height) ÷ 2
This assumes your loft has a pitched or triangular roof shape, which is common in most homes. Dividing by two gives a more accurate estimate by accounting for the sloping ceiling.
Example calculation:
If your extended loft measures 6 metres long, 4 metres wide, and 3 metres high:
(6 × 4 × 3) ÷ 2 = 36 cubic metres
This would fall comfortably within the permitted development limit for a semi-detached property.
These volume restrictions help maintain character and ensure your loft conversion complies with permitted development rights, avoiding the need for full planning permission. Always double-check your measurements and consult with a professional if you’re close to the limits.
In most cases, you won’t need full planning permission to carry out a hip to gable loft conversion, especially if your home falls under permitted development rights. However, there are some exceptions. Here's what you need to know.
Most hip to gable loft conversions fall under permitted development (PD), which means you can carry out the work without submitting a full planning application, as long as certain conditions are met.
To qualify, your project must:
Always check with your local authority or a loft conversion specialist to confirm your property qualifies before work begins.
You’ll likely need full planning permission if:
If your conversion does require planning, factor in additional time (typically 8–10 weeks) and costs for design drawings and application fees.
If you're planning a hip to gable loft conversion, the interior layout is where the transformation really comes to life. Thanks to the squared-off roof and extra headroom, this type of conversion opens up a world of layout and design possibilities, whether you're after a luxurious master suite, a bright home office, or clever storage solutions.
Below are some popular interior ideas to inspire your design:
A hip to gable loft is ideal for creating a spacious double bedroom. Use the sloped eaves to your advantage by installing built-in wardrobes, drawers or under-bed storage. Not only does it make smart use of the space, but it keeps the room clutter-free and open.
Pinterest inspiration: Bedroom with eaves storage.
Many homeowners opt to include an en-suite bathroom, making the most of the newly available floor space. Place the shower or bath under the eaves, and use skylights or dormer windows to bring in natural light. A corner layout or sliding door can help save space without compromising function.
Pinterest inspiration: Stylish en suite under loft eaves.
A quiet, private workspace fits perfectly beneath the new gable end. This setup gives you full ceiling height and the opportunity to add a desk with shelving or storage above. It's a great option if you're working from home or just want a calm corner to focus.
Pinterest inspiration: Home office in gable loft.
If you live in a semi-detached, end-of-terrace or detached home with a sloping side roof, a hip to gable loft conversion could be the perfect way to unlock extra space.
It’s ideal for families needing an additional bedroom or bathroom, homeowners working from home, or anyone looking to enhance their property’s value without having to relocate. If your roof has enough height and your property isn’t in a conservation area, it’s likely a strong option worth exploring.
Use our loft conversion cost calculator to get a tailored estimate for your home.
A hip to gable loft conversion can transform your loft into a spacious and functional area, but it's essential to weigh the benefits and limitations before making a decision.
Below, we outline the key pros and cons to help you determine if this type of conversion is the right choice for your home.
A hip to gable loft conversion significantly increases your living space, property value, and home aesthetics, all while being a cost-effective alternative to moving.
Here we look into it in more detail:
However, the conversion must adhere to strict volume and height restrictions, may require planning permissions, and can involve significant structural changes and costs.
Let's dive into these a little deeper:
Thinking about a hip to gable loft conversion but still have questions? Below, we’ve answered the most common queries homeowners ask, from planning rules and design options to how much space you’ll gain.
They’re most suitable for semi-detached, end-of-terrace, detached homes, and bungalows with hipped roofs. Mid-terrace properties typically aren’t appropriate.
Yes. Combining both is common and maximises internal space. It’s especially effective on semi-detached homes with limited loft height.
Yes, it alters the external shape of your roof, but when done well, it looks natural and can increase kerb appeal.
In most cases, no, they fall under permitted development. But if you’re in a conservation area or a flat, you may need full planning permission.
Most projects take between 6 and 10 weeks once construction starts, depending on the complexity and whether a dormer or en-suite is included.
It depends on your property, but it can add 10-20m² of usable floor space, often enough for a double bedroom and en suite.