Garden Room Extension in Edinburgh

DESIGN CONTEXT AND CHALLENGES

Nile Grove is a tree-lined avenue within the Morningside Conservation Area — one of Edinburgh's most cherished residential addresses — and this garden room extension in Edinburgh sits within a street of handsome Victorian semi-detached villas, predominantly built in the early 1880s. Working within a conservation area imposes real constraints on external alterations. Any intervention must be respectful of the established character of the streetscape and the building itself, and all works require listed building consent from the City of Edinburgh Council.

The existing conservatory — described by Lorn Macneal Architects as 'un-original and un-sympathetic' — had been added to the rear of the property at some point after the building's construction, and it sat awkwardly against the quality of the Victorian stonework. The owners, who had acquired the property with the intention of transforming it into a truly exceptional family home, wanted the new extension to do the opposite: to feel considered, contemporary, and deeply connected to the garden.

There were two distinct glazing challenges on this project. The first was the main garden room extension to the rear, which required floor-to-ceiling sliding glass doors with the slimmest possible profile — to maximise the visual connection between the new kitchen-living space and the extensive south-facing garden without introducing heavy frames that would detract from the sense of openness the architect was seeking. The second was an underused exterior courtyard space, shaded and enclosed by the existing stone walls, which was to be transformed into a light-filled studio by glazing it overhead.

Both challenges required glazing systems that could deliver thermally broken, triple-glazed performance critical in Edinburgh's climate — while maintaining the refined minimal aesthetic the architect and client had specified. The conservation area context meant that visual impact was under scrutiny throughout, and every detail of the glazing specification needed to support the argument for consent.

PERFORMANCE CONSIDERATIONS

Edinburgh's climate demands serious thermal performance from any glazing system. The city sits significantly further north than most of the UK, with cold winters, persistent wind exposure, and frequent rain. A floor-to-ceiling glazed elevation that performs poorly thermally would undermine the very comfort and liveability that the new extension was designed to create.

The Keller minimal windows 4+ system was specified precisely because it combines extreme visual slimness with serious thermal engineering. The 4+ designation indicates the system's thermally broken construction, and in combination with triple glazing, the system achieves Uw values of ≥ 0.70 W/m²K. The flush threshold detail on the sliding track creates a seamless internal floor-to-terrace transition — removing the trip hazard of a raised sill while maintaining a fully weather-tight seal against driving Edinburgh rain.

The Invisio structural glazing system brought its own set of performance requirements in terms of this garden room extension in Edinburgh. The structural glass panels needed to be independently load-bearing, thermally broken, and capable of integrating with the existing stone courtyard walls without visible fixings. IQ Glass worked with the project team to design a fixing detail that transfers load to the stone wall without compromising the frameless visual quality of the finished installation.