The brief

Rebuild the back of a cold 1890s semi as a kitchen and garden room the family would use in January, without touching the original bay and cornicing at the front.

What we did

Took the rear wall back to a steel frame, laid an insulated slab under an oak-framed garden room, fitted triple glazing and an air source heat pump, and restored the front rooms by hand.

The result

61%

lower heating bills in the first winter, against the meter readings from the winter before. Finished a week early and £4,200 under the agreed price.