Cassion Castle Architects is an award-winning architecture practice, based in London. Founded in 2006 and led by Cassion Castle, we are dedicated to the creation of well-crafted, quality designs for both residential and commercial clients. Our understated buildings and spaces can be found in a range of locations, from small urban plots to rural green-field sites.

We believe that design solutions flow naturally and most successfully when the specific context of each project is examined carefully and then considered alongside the client's particular requirements. Emphasis is always placed on thoughtful design and craftsmanship. We aim to use natural, textural materials - wood, stone, metal, concrete - transcending trends, in order to create timeless and elegant design. We believe that good design can radically enhance the ability of our clients to carry out their everyday activities.

Current residential projects include: Chalk House - a Paragraph 55, zero-carbon house in the Kent downs, made from compressed chalk quarried from its own site; Bar Lane - a trio of new-build houses in the Cambridge countryside; Chandos Court - a penthouse development on the top floor of a 60's block in North London; and Albert House – the re-development of a small, urban outbuilding, into a compact three-storey dwelling. Recently completed commercial work includes the design of a Giacometti exhibition for Luxembourg & Dayan Gallery, and the creation of two new centres for Triyoga, London’s leading yoga company.

The practice has received prestigious RIBA and Manser Medal award nominations for our work. In 2016 Oak Lane House won The Daily Telegraph award for Best Residential Design, the same year Cassion Castle was a finalist in the BD Architect of the Year Awards.

Our work has been exhibited at the RIBA and published extensively in books, magazines, and the national press, including features in The Daily Telegraph and The Sunday Times. We are proud to be included in the Architecture Foundation's recent publication: "New Architects 3 - A Decade of British Talent".


Cassion Castle BA Hons (Cantab), MA (RCA), RIBA

Cassion was born in London in 1972. His interest in buildings and construction begun at an early age, inspired by his father who is also an architect.

He began his formal training at Cambridge University after which he completed a Masters Degree at The Royal College Of Art, where he was taught by David Adjaye and Zaha Hadid. Prior to establishing his own practice, Cassion worked for various architectural offices including Florian Beigel's Architecture Research Unit, Paxton Locher and Dominic Cullinan, where he gained valuable and varied experience. Cassion completed his training at the Architectural Association, receiving his professional qualification in 2001. He established Cassion Castle Architects, an RIBA chartered practice, in 2006.

A keen interest in materials and the practical craftsmanship of making informs the practice's design approach, and has lead to the evolution of an affiliated construction company: Cassion Castle Construction.

Cassion has been a member of the RIBA small practice group since 2014. The main output of this group is the Guerrilla Tactics conference at which he is a regular speaker. Cassion has been invited to judge and present the RIBA London Awards 2018.


Cassion leads a creative and experienced team, yet the practice is deliberately kept at a size which enables him to carefully oversee the design and delivery of every project, remaining directly involved in all aspects of the process. 

The multi-disciplinary studio offers a full range of services which include: architectural design, interior design and decoration, bespoke joinery design and fabrication; in addition to project management and full construction services via our sister company Cassion Castle Construction.

We do not build everything that we design and nor do we design everything that we build, the two arms of the company work independently of one another in a flexible way that can be tailored on a project by project basis to meet the needs of each individual client.

We have strong working relationships with other independent professionals: fabricators, engineers, quantity surveyors and landscape designers, which enables a collaborative and design focused approach to projects of any scale. 



Architects' Journal Cassion Castle wins approval for Paragraph 55 home


Architects' Journal Oak Lane House


The Times  An Architect For Any Job


Concrete Coast House, Southern England


Elle Decoration The Directory


Architecture Today Cassion Castle Architects - Coast House


Dezeen Photography studio by Cassion Castle


Dezeen Castle's studio embracing "timber & craftsmanship"


Architects' Journal Long Sutton Studio, Hampshire


The Independent Is This The New Face Of The Modern Home?


Architectural Review  Living in a Box


Building Design Castle Plans a Stealthy Citadel for Bethnal Green


Architects' Journal  AJ Small Projects Part 2


Wallpaper* 40 Fabulous Reasons To Be Exactly Where You Are


Plan Magazine Small Projects Part 1


Architects' Journal  Dunne Raby Studio


Building Design  Village Pavilion Makes Its Debut


Total Production Park Life With The Metal Gurus


FRAME Bargain Basement


Wallpaper* Take Slat


Grand Designs Magazine  The Best Homes and Products of 2009


Metro Extending Your Dreams


Contract - Inspiring Commercial Design Solutions Shiny and New


Business Life Office of the Month: McCann Erickson


FX Steeling Beauty


IdFX Hidden Depths


Financial Times Where the People Provide the Colour


The Sunday Telegraph Double Act


Building Design Summerhouse: Stoke Newington, London


Grand Designs Simple, Sam Says


Creative Base Underexposed


The Guardian Space Young Guns go for it