
Retrofit for Living: How can you make existing housing zero carbon?
Transformational changes have been made to this 1990s Dockland house to bring about highly efficient energy use and an improved quality of living for the residents, whilst minimising visual impact on the neighbourhood.
The completed project is currently undergoing a 2-year period of energy and environmental monitoring. The predicted CO2 emissions after retrofit are 16kg/m²/yr – a reduction of 79% from the 1990 baseline for average UK social housing.
Without extending the house, the internal environment has been transformed by the creation of a ventilating lightwell within the existing loft space to provide fresh air, daylight, amenity space and a clothes drying area. Accessible temperate storage is provided in the residual loft.
Innovations include:
- Triple-glazed windows with ventilating panels and louvers for secure day and night ventilation;
- A new product developed by Penoyre & Prasad and the window manufacturer;
- A ‘breathing’ roof to dissipate moisture, using natural insulation products (wood fibre slab and hemp quilt) with an intelligent vapour control membrane;
- Vacuum insulation panels in the floor for high thermal performance with minimal (25mm) rise in floor level.

1. Existing masonry cavity wall with facing brickwork
2. Existing suspended concrete floor with screed finish
3. Existing brickwork parapet with concrete copings
4. Existing timber trussed rafters adapted
5. Timber beams inserted between party walls
6. Existing roof tiles retained to lower parts of roof
7. 90mm rigid PIR foam internal insulation to front wall
8. 120mm rigid phenolic foam external insulation to rear wall
9. Gypsum plasterboard on battens and vapour control layer
10. Silicone render finish to rear wall
11. 20mm vacuum insulation panels (VIPs) with cellular polyethylene foam sheet protection
12. Thin galvanised steel sheets as puncture protection to VIPs
13. Wood floating floor
14. 300mm hemp-flax quilt insulation to existing ceiling
15. 100mm rigid wood fibre insulation above rafters
16. 75+225mm hemp-flax quilt insulation between and below rafters
17. Intelligent vapour control layer with moisture vapour permeable lining
18. Existing roof tiles re-laid to area of raised roof
19. Triple glazed aluminium rooflight with automatically opening lights
20. Triple glazed composite wood aluminium windows with secure ventilator panels
21. Composite wood aluminium front door
22. Triple glazed composite wood aluminium rear door
23. Solar ventilating lightwell with mezzanine, space saver stair and clothes drying space
24. Loft storage space
25. Solar photovoltaic panels to front roof
26. Solar thermal panels to rear roof
27. Existing gas combi boiler fitted with flue gas heat recovery system
Elements not shown for clarity: Party walls with cavity fill insulation, insulated dry linings to party walls in mezzanine and loft spaces, solar thermal storage tank in roof.