A belief in the value + benefits of good modern design underpins the horncastle:thomas approach to every project. Always considering context, environment, local Island constraints + levels of craft. Combining design technology with a keen + careful understanding of the past, horncastle:thomas retain an aspiration to find quality in the slightest of projects
Both RIBA Chartered Architects, Karen Horncastle + Martyn Thomas formed horncastle:thomas in the Isle of Man in 2011: Karen has worked in the Isle of Man for over thirty years; Martyn worked for two leading architectural practices in North West England before returning home in 2010
Together they have worked on a range of existing and new building types, and have developed an affinity for working on listed and registered buildings and buildings in conservation areas, new + old
Karen retired at the end of May 2026 and after 15 years in practice together Martyn is continuing and is in the process of building a new team
In addition to the practice's current work, this website includes projects undertaken for previous employers + collaborators (as credited)
horncastle:thomas is a RIBA Chartered Practice
We have always valued teamwork and currently work alongside Alex Bowers, Finbar Samson + Lana Bell
In recent years we have enjoyed working with Andrew Traynor, Raquel Pueyo, Fariba Shaban Poor, Betty Laurincova, Patricia Tutt, Laura Jones + Rania Gomaa