Scottish practice Architecture Office has extended Cairngorm Cottage, a Victorian home in rural Aberdeenshire, Scotland, replacing a small, dark 1970s rear extension with a new kitchen, dining room, utility room, and entrance hall. Combining reclaimed local granite with clay-block construction, the extension provides space for family gatherings while retaining the modest proportions and material character of the original cottage.

The clients purchased the property in 2016 and wanted to accommodate extended family and friends without losing the intimacy of the existing home. Architecture Office responded with a masonry extension that draws on the cottage's scale, solidity, and natural materials, using thick walls and deeply recessed openings to establish continuity between the old and new structures.

An extension shaped by its setting

Cairngorm Cottage is situated within a Victorian village on the edge of the Cairngorms National Park, with connections to the Balmoral estate and a distinct local building tradition. The extension takes cues from the original cottage's proportions, orientation, roof levels, openings, and stone coursing.

Following the orientation of the existing building, the new volume reduces its projection into the garden and shortens the side elevation. From the street, it remains within the established building line and sits lower than the original house, maintaining the cottage's prominence.

The reconfigured layout improves circulation between the old and new parts of the house. A new entrance hall and boot room connect the extension with the existing living accommodation, while a side entrance provides access to the kitchen. Repositioned doors establish clearer routes between the living spaces and garden.

Facing northwest, the kitchen and dining areas open towards the garden. Deeply recessed openings introduce ambient daylight and frame views of the landscape without relying on extensive glazing.

‘The clients wanted the house to accommodate family life across generations, while retaining the character of the original cottage,’ explains Alexander Mackison, Director of Architecture Office. ‘We were interested in what gives a cottage its particular identity and how those qualities could be carried into a contemporary addition. Granite and clay became a way of connecting the old and new through material and construction.’

Reclaimed granite and clay-block construction

The extension uses a clay-block wall system selected for its thermal performance and thermal mass. The construction combines insulation and heat storage within a vapour-open wall assembly, helping to moderate internal temperature fluctuations. During winter, the thermal mass can absorb heat and release it gradually as temperatures fall, contributing to more stable indoor conditions.

The walls measure 705 millimetres thick, with reclaimed local granite forming the outer 300 millimetres. Sourced from nearby sites, the stone was selected for its variation in colour and size, including warm peach-pink tones that relate to the original cottage. Rather than standardising the reclaimed material, Architecture Office retained the individual stones as found, aligning their coursing with the existing cottage and the masonry traditions of Aberdeenshire.

A traditional slaistered lime mortar finish, in which mortar is spread generously around and across the stone joints, gives the rear elevation a continuous, monolithic appearance. Deeply recessed openings emphasise the thickness of the masonry and frame views towards the garden.

Aluminium coping, gutters, downpipes, and vents introduce a precise contemporary contrast to the irregular texture and mass of the granite.

Embodied carbon was considered as part of the project's sustainability brief, although no project-specific assessment data is available. The clients prioritised natural materials sourced locally where possible, including the reclaimed granite and Scottish ash used for the interior joinery. Stone worktops and clay plaster finishes were sourced from elsewhere in the UK.

‘We wanted the building to feel substantial and modest, drawing on a stereotomic architecture of mass, depth, and carved openings,’ says Mackison. ‘The clay block and granite construction allow the openings to feel cut from the building, giving the new rooms a sense of shelter, permanence, and continuity with the original cottage.’

Natural materials and integrated joinery

Internally, clay plaster, Scottish ash joinery, oak flooring, and Yorkshire stone worktops establish a restrained material palette. Architecture Office designed the extension, kitchen, and fixed joinery as a single composition, maintaining continuity between the architectural detailing and interior finishes.

The Scottish ash joinery, fabricated by Silvan Studio, uses three-ply timber construction with exposed grain and vertical staves. Individual kitchen units are arranged around a central island, providing space for food preparation and informal gatherings.

Oak flooring introduces a contrasting timber surface, while Yorkshire stone worktops provide durable working areas. Clay plaster contributes subtle variations in tone and texture throughout the interior, complementing the exposed timber grain and natural stone surfaces.

‘The clay plaster has subtle tonal and textural variation, while the grain and vertical staves of the timber kitchen give each surface its own character,’ Mackison explains. ‘These material qualities bring a softness and human presence to an otherwise restrained interior.’

By combining reclaimed masonry, clay-block construction, and natural interior finishes, Architecture Office has extended the cottage's accommodation while maintaining its relationship with the surrounding village and landscape.