A whole-house retrofit in North Oxford, delivered by Lambert Home Builds as part of a Cosy Homes Oxfordshire Whole House Plan.
The Brief
Jane’s 1910 semi-detached home had plenty of character but very little warmth. Solid brick walls, a suspended timber floor, and years of partial upgrades had left it draughty, cold in places, and expensive to heat — her home office in particular was, in her words, “freezing.” Working with Cosy Homes Oxfordshire’s fabric-first Whole House Plan, Lambert Home Builds was brought in to carry out the insulation and fabric improvements that would prepare the house for a heat pump.
The Work
Our team delivered:
- Internal wall insulation — around 67 sqm of woodfibre insulation and lime plaster across the sitting room, a bedroom, the study, and part of the family room
- Suspended timber floor insulation beneath the sitting room, paired with new underfloor heating
- Intermediate floor insulation (Rockwool between joists) for improved acoustic and thermal performance
- Roof and joist-level insulation (300mm Rockwool) above the sitting room extension
- Replacement windows and an external-grade front door, upgrading to double-glazed energy-efficient sashes
- Centralised extract ventilation, installed to keep the newly airtight home fresh and moisture-free
All work was specified and sequenced as part of a coordinated Whole House Plan, with materials chosen to suit the age and construction of the property — breathable woodfibre and lime systems for the solid walls, keeping the building fabric healthy while dramatically improving comfort.
Curious how this system works? See our Internal Wall Insulation FAQ.
The Result
The transformation was immediate. Jane described feeling her study warm up as the woodfibre insulation went in — it’s now the warmest room in the house. With insulation, floor heating, and ventilation in place, the whole home is noticeably warmer and more comfortable, setting it up for the air source heat pump that followed.
“My study was freezing cold, but now it’s the warmest room in the house!” — Jane
Certified and Guaranteed
The project was signed off with Building Control certification, FENSA certification for the windows and door, and manufacturer warranties across all major measures — giving Jane long-term peace of mind alongside the day-to-day comfort.
Lambert Home Builds is proud to work alongside Cosy Homes Oxfordshire, delivering fabric-first retrofit measures that make older homes warmer, greener, and cheaper to run.
