Architecture Studio · London
Rosace Design Studio is a London architecture and construction practice specialising in extensions, loft conversions, new builds and interior architecture - designed with precision, built with care.
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What We Do
Rosace Design Studio is an architecture and construction practice based in London. We design and build residential projects across Greater London and within a 30-mile radius, from single-storey kitchen extensions to substantial new build homes.
What sets Rosace Design Studio apart is that we are both the architectural designer and the builder. Most practices do one or the other. We do both, under one contract, with one team. That means there is no gap between what gets designed and what gets built. No finger-pointing between firms. No surprises when the builder prices a design that was drawn without any thought for buildability or budget.
We take on a manageable number of projects at any time so that every client gets our full attention. Our work spans house extensions, loft conversions, new build homes, basement conversions, HMO conversions, and interior architecture. We also handle all planning applications in-house.
Whether you are considering a rear extension on a Victorian terrace in Islington, a mansard loft conversion in Wandsworth, or a new build home in Surrey, we can visit the property, assess the potential, and give you an honest view of what is achievable before you commit to anything.
How we work
Every project begins with a conversation. We visit your property, listen to your brief, and give you an honest assessment of what is achievable within your budget and within the planning framework that applies to your site.
From there, we develop design options, prepare and submit planning applications where required, produce detailed construction drawings, and build the project with our own construction team. You deal with one practice throughout, and one point of contact manages your project from start to finish.
This model means you get realistic cost guidance from day one. Our architectural designers design with buildability in mind because they work alongside the people who will actually construct it. The result is fewer surprises, tighter programmes, and a finished project that matches the design.
Services
Whether you're extending a Victorian terrace in Hackney or building a new home in Surrey, Rosace brings the same level of design rigour and project management to every commission.
01
House Extensions
Rear extensions, side returns, wrap-arounds and double-storey additions - designed to complement your home and your lifestyle, managed from concept to completion.
Learn more →02
Loft Conversions
Mansard conversions, rear dormers, hip-to-gable and velux conversions - architecturally designed and fully managed from planning application through to handover.
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New Build Homes
Substantial new build projects - from initial feasibility and planning through to building regulations and construction oversight. Designed around how you want to live.
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Planning Applications
Full planning applications, householder applications, listed building consent and prior approval - managed with established knowledge of London's planning authorities.
Learn more →05
Interior Architecture
Space planning, specification, joinery design and FF&E - designed in-house and coordinated to the same standard as the architecture. Available as part of any project or as a standalone commission.
See interiors →06
Basement Conversions
Full basement excavations and lightwell conversions - requiring careful structural coordination and planning management. Rosace has experience delivering basement projects across London.
See projects →Where We Work
Rosace Design Studio works across Greater London and the surrounding counties, with established relationships with local planning authorities and a strong understanding of what works - architecturally and commercially - in each area.
Our projects range from Victorian terraces in Hackney and Camden to grand townhouses in Kensington and Mayfair, and significant new builds in Surrey.
Areas Covered
How It Works
01
Initial Meeting
We visit your property, discuss your brief and budget, and give you an honest assessment of what is achievable. We check the planning position and flag anything that could affect the project before you commit.
02
Design Options
We develop design options at different scales and budgets, so you can see what is possible and make an informed choice. Once you settle on a direction, we refine the design into a full set of drawings.
03
Planning & Technical
We prepare and submit the planning application or PD notification, handle all council correspondence, and produce full construction drawings coordinated with structural engineers.
04
Build & Handover
Our in-house construction team builds the project. We manage the programme, handle building control, and keep you informed throughout. One point of contact from start to finish.
Fees & Costs
Architectural fees for residential projects in London typically range from 8 to 15 percent of the construction cost, depending on the scope and complexity of the project. Smaller, more straightforward projects such as a single-storey rear extension tend to sit towards the lower end. Larger, more complex projects like new builds or basement conversions tend to sit higher.
For a house extension with a construction cost of £80,000, architectural fees would typically be between £6,400 and £12,000. For a new build home costing £500,000 to construct, fees might range from £40,000 to £75,000, reflecting the greater amount of design and coordination work involved.
Rosace Design Studio provides a clear fee proposal at the outset so you know exactly what to budget. Because we also handle the construction, our combined design-and-build fees are often more competitive than appointing an architectural designer and a builder separately.
Our Approach
The biggest frustration homeowners face with residential projects is coordination. The architectural designer designs something, the builder prices it higher than expected, and nobody takes responsibility for the gap. Meanwhile the project stalls and costs climb.
Rosace Design Studio eliminates that problem. We are both the design studio and the builder. Our design team creates the drawings, and our construction team builds from them. There is no handover gap, no miscommunication between firms, and no finger-pointing when something needs resolving on site.
This model also means you get realistic cost guidance from day one. We design with buildability and budget in mind, because the people drawing it work alongside the people who will build it.
Common Questions
