A loft conversion is one of the most effective ways to add value, space, and comfort to your London home. By transforming an unused loft space into a bright, functional living area, you can unlock the full potential of your property – whether you’re looking to add a bedroom, home office, or private suite.
At Armstrong Simmonds Architects, we specialise in bespoke loft conversions tailored to the unique architecture of London’s residential properties. As a RIBA Chartered architect studio, we guide you through the entire process; from feasibility and planning to design, detailing, and construction oversight.


A successful loft conversion requires more than just floorplans and building work – it needs architectural thinking. We approach every project with a deep understanding of space, light, structure, and context.
Our service includes:
We deliver loft conversions that look and feel like a natural extension of your home, not an afterthought.
Our design team also takes into account the property’s original features, such as chimneys, dormer constraints, or roofline variations. We consider head height, fire regulations, stair placement, and daylight orientation, ensuring every detail is thought through from the start.
Every home is different, and so is every loft. Our team of residential architects will advise you on the best solution for your property and ambitions.
1. Dormer Loft Conversion
The most popular option in London, a dormer adds a full-height extension to the rear roof slope, maximising internal space and headroom. Ideal for double bedrooms and en-suite bathrooms.
2. L-Shaped Dormer
A variation of the standard dormer, this layout is perfect for period terraced homes with rear outrigger roofs. It provides extra floor area and is particularly suited for large master suites or home offices.
3. Mansard Conversion
A more dramatic transformation that involves rebuilding the roof slope at a steeper angle. Mansards provide a more elegant design and are typically required in conservation areas, specific boroughs or properties with certain roof types.
4. Hip-to-Gable Loft Conversion
This method converts the sloping side roof (hip) into a vertical gable wall, expanding the loft floor plan. It’s commonly used in semi-detached or end-of-terrace homes.
5. Velux Loft Conversion
The most cost-effective option, a Velux (or rooflight) conversion keeps the existing roof structure intact while adding roof windows and insulation. Perfect for studies or guest bedrooms.
If you’re unsure which option best suits your home, we’ll assess your property, planning context, and long-term needs during the design phase – ensuring you make the right decision.

We combine creative thinking with technical expertise to guide you through every stage of your project from concept to completion. The process typically includes the following key phases:
