Musician Effie Galletly’s 1930s two-storey family house stands on a hillside above the city of Bath. She has recently extended this family home to incorporate a music studio, a 12 x 6m oak-framed building with large windows in the gable giving fine westerly views over the garden and the city. It includes a mezzanine workroom, a new garage at the rear, a shower and utility room, and a ‘boots’ area which links the studio to the house.
Galletly’s concept for the studio - a timber-clad New England boathouse on an ashlar podium - was developed in discussion with Joe Cunningham of Edward Nash Architects. The studio replaces an original stone garage, and Galletly was concerned to re-use materials already on the site. It is built with ecologically sound materials and techniques: the structure is a green oak frame, exposed on the inside; there are high levels of natural light and insulation; low permeability; and roof rainwater is stored in a large tank in the undercroft.
After the plan was finalised and planning permission obtained, Michael Dickson, Galletly’s husband and chairman of Buro Happold, carried through the details and work on site.
To accommodate the sloping site, the oak frame sits over an ‘armchair’- shaped structure formed by the ashlar and blockwork garage behind it and the undercroft below it. The floor of the studio is formed from 155mm- deep Bison hf beams and 440 x 215 x 100mm concrete blocks grouted together.
The roof structure comprises three green-oak cross-frames with intermediate trusses between them. Fifteen pairs of 75 x 100mm common rafters sit on 125 x 150mm purlins that span the trusses and the cross frames; these are scallop-notched into the inclined members of the trusses to allow installation during construction. The pitched clay-tiled roof, on battens, counterbattens, vapour barrier and insulation, is laid on a white-painted plywood ceiling screwed to the rafters and the truss members. Together with 175 x 32mm windbraces to the intermediate trusses, the ply ceiling acts as a rigid roof diaphragm.
The green oak was rough sawn and jointed together with pegged mortice- and-tenon and dovetailed dowel joints.
The studio walls are formed of frames of 150 x 150mm oak posts. The site is exposed, and to give lateral stability the west elevation is braced with concealed hardwood struts and two pairs of oak cross-frames are fixed down to the rigid masonry base structure.
Softwood sub-frames between the oak frames support battens for the external cladding of oak lap boarding, breather membrane, 12mm plywood and rigid polyisocyanate-foam insulation boards.
On the north wall, close to the boundary of the site, the lap boarding is replaced by sand/ cement render finish on expanded metal lath to comply with fire regulations.
The studio floor is of 18mm tongued-and-grooved maple boards on 65mm floor battens with rigid insulation between. In order to incorporate a heating unit below the large west-facing studio windows, the 100mm concrete blocks which sit on the lower flanges of the Bison floor beams have been replaced by 48mm concrete pavers. This created sufficient space below the finished floor level to let in a heating unit; it is covered with a 10mm charcoal-coloured metal grille. The floor is fitted with flush electric floor sockets.
The interior finishes are designed as simple planes which form a background to the strong forms of the structural oak frame. The painted internal plasterboard linings were each cut as one piece and recessed into the frames, secured with a mastic joint.