Building: Nethermill House, Auchterless, Aberdeenshire

Architect: Kirk Natural Stone Ltd

Stone type: Balmoral grey granite laid randomly; pink granite cassie detailing; Caithness flag window cills and kitchen worktops; natural slate roof

Construction type: Cavity Wall

A traditional-style house, Nethermill nevertheless demonstrates what can be achieved by builders and developers willing to use locally-available natural materials. In this instance, constructing a new property from locally-sourced grey granite, Caithness flag cills and natural slate might be seen as a bold move for a relatively small company but the use of these materials provides a solid and timeless feel to the house and adds significantly to its value. This is an unusually large family home comprising some 500 square metres of accommodation (including a kitchen, dining room, galleried hallway, utility room, shower room with hot tub, lounge, 4 bedrooms and guest room, en-suites and additional bathrooms, games room, conservatory and integral double garage and store) which, despite the granite being randomly laid, was constructed relatively quickly.

Conventional cavity wall construction was used at Nethermill House but, based upon this experience and working in conjunction with Angus Homes Ltd on a project for a site in Turriff, Kirk Natural Stone Ltd are now developing a more economical timber frame kit package which can be used with either random or dressed stone. In this system, an internal lining of plasterboard is separated from a structural timber frame by a vapour check. A thick, CFC-free insulating quilt is sandwiched between the timber uprights and is backed with a sheathing board. A waterproof breathing membrane separates this from the cavity framing, and is itself fronted with sheathing board and a further waterproof membrane. The natural stone outer skin completes the external envelope.