Projects · 07 of 08 · completed June 2024
Garden room for a piano teacher
Two and a half metres of permitted height, a cherry tree that was not going anywhere, and a piano that needs a stable room. The height limit shaped everything.
The brief
Our client teaches piano, eleven pupils a week plus her own practice, from the front room of a stone cottage. The room is next to the kitchen and below the main bedroom, and it had stopped working for the whole household some years before anyone said so out loud. Parents waited in the hall. Lessons stopped when the kettle went on.
She asked for a room in the garden that would take an upright piano, two people, and a parent waiting. She wanted to be able to teach in it in February. And she wanted it to be a proper room, not a shed with a radiator, because she is in it fifteen hours a week.
What made it difficult
The obvious site was within two metres of the boundary, and under permitted development an outbuilding in that position is limited to 2.5m in total height. That is a hard number and it governs everything above it: the floor build up, the insulation depth, the ceiling height and the roof.
A cherry tree stood four metres from the proposed corner and the client was clear that it stayed. Its root protection area ruled out a conventional strip foundation on that side.
Sound had to work in both directions. Pupils should not hear the road, and the neighbours should not hear the pupils, some of whom are eight years old and learning scales.
Heating was the other problem. Running a spur off the house system meant a trench, a pump and a pressure question the existing boiler was not going to answer well.
What we did
The 2.5m limit was met by digging rather than by building low. A shallow excavation dropped the finished floor 250mm below external ground level, with the ground falling away slightly on that side so drainage still worked. Internal height came out at 2.35m, which is a proper room, and the building reads as low and quiet in the garden rather than as a box.
Foundations were screw piles on the tree side and a conventional pad on the other, which kept machinery and excavation out of the root protection area entirely. An arboriculturalist's method statement cost £480 and took a morning. It was worth it.
The walls are a timber frame with 140mm of wood fibre insulation, chosen over mineral wool partly for its acoustic mass and partly because it handles moisture better in a small heavily used room. Externally, larch boards laid horizontally, left to silver. Internally, plasterboard on resilient bars, which is the detail that does most of the acoustic work.
Glazing is on two elevations. A 2.4m sliding door faces the garden and a high slot window faces the boundary, set above eye level so the room gets morning light without either party looking at the other. The piano sits on the internal wall away from both, because pianos do not like a window.
Heating is a single electric panel heater on a programmable thermostat, sized for a room this well insulated, plus the underfloor insulation to make it work. Running cost through the first winter came to about £11 a month. A wet system would have cost £4,000 to install and saved nothing meaningful at this scale.
Parents wait inside now. There is a bench, a shelf, and a door that closes.
What it cost
£36,080 against a range of £34,000 to £39,000. That is a genuine range that we could give with confidence because the building is small, simple and entirely new, which is the easiest kind of thing to price. Renovation is where ranges get wide, for the reasons set out in how to budget a renovation without lying to yourself.
The breakdown: groundwork and piles £6,400, frame and envelope £15,800, glazing £5,900, internal finishes £4,300, electrics and heating £2,900, arboriculturalist and drawings £780.
No planning application was needed, because the design was kept inside permitted development. We did apply for a lawful development certificate at £129, which is not required but is the cheapest insurance available when a building sits close to a boundary.
Our fee was £3,800 for the full design package plus the certificate application. Our client ran the build herself with a timber frame contractor we introduced her to, which on a small new building with no existing fabric to surprise anyone is a reasonable thing to take on.
What we would do differently
We would put a second socket by the door. It sounds trivial. She now teaches two pupils at once occasionally, using a keyboard alongside the piano, and the only sensible position for it is the one place in the room with no power.
