Dormer vs L-Shaped vs Hip-to-Gable

A loft conversion is one of the most cost-effective ways to add space and value to your home. But with several types of loft conversions available, many homeowners ask the same question:

Which loft conversion is right for my house?

At NFA Design & Build, we regularly advise homeowners across the UK on the three most popular loft conversion types: Dormer, L-Shaped, and Hip-to-Gable. Each has different benefits, planning implications, and suitability depending on whether your home is terraced, semi-detached, or detached.

This guide breaks it all down clearly—so you can make an informed decision before you start.

Why Choosing the Right Loft Conversion Matters

Not all lofts are the same. Choosing the wrong conversion type can lead to:

• Planning permission refusal

• Poor use of space

• Higher construction costs

• Limited return on investment

The right loft conversion, however, can:
✔ Add up to 20–25% property value
✔ Create a spacious bedroom, office, or ensuite
✔ Avoid the cost and stress of moving

Let’s explore your options.

1. Dormer Loft Conversion – The Most Popular Choice in the UK

What Is a Dormer Loft Conversion?

A dormer loft conversion extends vertically from the existing roof slope, creating additional headroom and usable floor space. It typically includes a flat roof and large windows or doors.

Best Suited For:

• Terraced houses

• Semi-detached houses

• Some detached homes

Key Benefits:

• Maximises internal space

• Excellent natural light

• Cost-effective compared to more complex conversions

• Highly versatile layout options

Planning Implications:

In many cases, a rear dormer loft conversion falls under Permitted Development, meaning planning permission may not be required (subject to size limits and conditions). However, homes in conservation areas or with previous extensions may still require approval.

2. L-Shaped Dormer Loft Conversion – Maximum Space for Period Homes

What Is an L-Shaped Loft Conversion?

An L-shaped conversion combines a rear dormer with an extension over the rear outrigger, forming an “L” shape when viewed from above. It’s commonly found in Victorian and Edwardian properties.

Best Suited For:

• Victorian terraced houses

• Edwardian terraced houses

• Some end-of-terrace homes

Key Benefits:

• Creates the largest amount of loft space

• Ideal for master bedrooms with ensuite bathrooms

• Excellent layout flexibility

• Significant value uplift

Planning Implications:

Many L-shaped dormers also fall under Permitted Development, but the larger scale often means closer scrutiny. Accurate drawings and compliance with volume limits are essential.

3. Hip-to-Gable Loft Conversion – Perfect for Semi-Detached & Detached Homes

What Is a Hip-to-Gable Loft Conversion?

This type of conversion extends the sloping “hip” side of the roof into a vertical “gable,” increasing the internal roof volume. It’s often combined with a rear dormer for maximum space.

Best Suited For:

• Semi-detached houses

• Detached houses

• End-of-terrace properties

Key Benefits:

• Significantly increases usable loft space

• Creates a more symmetrical roofline

• Ideal for larger family homes

• Works well with modern layouts

Planning Implications:

Hip-to-gable conversions often require planning permission, especially when altering the roof shape. Local authority approval is more likely needed, making professional design and planning support essential.

Loft Conversion Suitability by House Type

🏠 Terraced Houses

Best options:

• Rear Dormer

• L-Shaped Dormer (for period homes)

Usually unsuitable:

• Hip-to-Gable (unless end-terrace)

🏡 Semi-Detached Houses

Best options:

• Hip-to-Gable

• Dormer

• Hip-to-Gable + Dormer combination

🏘️ Detached Houses

Best options:

• Hip-to-Gable

• Large Dormer

• Bespoke loft designs

Planning Permission vs Permitted Development

Many homeowners are surprised to learn that not all loft conversions need planning permission.

However, planning is usually required if:

• You exceed volume limits

• You alter the front roof slope

• The property is in a conservation area

• The design impacts neighbouring properties

At NFA Design & Build, we assess your property early and guide you through:
✔ Planning permission
✔ Permitted development compliance
✔ Building regulations approval

How Much Does a Loft Conversion Cost in the UK?

While costs vary, rough estimates are:

• Dormer loft conversion: £40,000 – £55,000

• L-shaped loft conversion: £50,000 – £65,000

• Hip-to-gable loft conversion: £45,000 – £70,000

A proper assessment is essential to avoid hidden costs.

Why Choose NFA Design & Build?

We offer a complete design-and-build service, meaning you don’t have to coordinate multiple consultants or contractors.

What We Do:

✅ Feasibility assessments
✅ Architectural design & planning
✅ Structural calculations
✅ Building regulations
✅ Full construction & project delivery

Our approach saves time, reduces risk, and ensures your loft conversion is done right—from concept to completion.

Ready to Find the Right Loft Conversion for Your Home?

Every home is different—and so is every loft. The best way to know what’s possible is to speak with an expert.

Book a FREE Loft Conversion Consultation with NFA Design & Build
📍 Serving homeowners across the UK
🏡 Tailored advice for terraced, semi-detached & detached homes

👉 Contact us today and unlock the full potential of your loft.