Two Victorian terraced houses combined into a family home
The Neely family enjoyed living in their terraced house in Cambridge, but the growth of their family meant they needed somewhere larger to live. When their neighbour's property came up for sale, it provided an ideal opportunity for them to extend their living space without moving away from the area.
The two adjacent Victorian houses, located in a conservation area, were renovated, extended and converted into one large family house. The brief was to provide modern, spacious family accommodation using environmental best practice.
The requirement was to provide: a contained entrance hall with lobby and storage; a large lounge; a kitchen; a family eating space/dining room; a children's space/room; a utility room with secondary access; five bedrooms; a bathroom; a second bath/shower-room or ensuite; use of loft space; a wine store; and an external patio area.
Natural materials with low embodied energy were selected for use on the project and included natural/organic paints, timber and slate finishes, natural waxes and stains. PVC-U products were avoided. To improve health standards in the house, non-toxic and low -VOC materials were chosen. Carpets and other fabrics were avoided in an effort to limit dust mites. Natural daylight and ventilation were also employed.
A dry lining system with 100mm of insulation was used to insulate the solid brick internal walls of the original structures. The levels in the existing extension and the new one were increased by 200mm (100mm full-fill cavity wall insulation and 100mm dry lining insulation). Very limited roof space in the attic room - which the new design allocated to workspace, a spare room and an en-suite - meant little headroom, so 200mm of insulation was fitted between the rafters and then battened out for a further 25mm of reflective insulation and plasterboard lining.
On the ground floor, the existing suspended flooring was replaced by a solid floor with underfloor, low-temperature water heating and 200mm of insulation underneath. Damp penetration was prevented with the use of membrane protection.
Windows and doors
The new windows to the rear and sides of the property are triple-glazed, with low-e glass on two of the panes, argon-fill and insulated spacer bars giving a U-value of 1.0W/sqmK.
The Victorian sashes at the front of the property have been replaced with double-glazed and draught-stripped timber windows, which match the original style. In the bays, the roofs and side walls were insulated when the windows were replaced. There is even an insulated and airtight cat flap!
The building achieved 5 air-changes per hour at 50Pa in a fan pressurisation test. As the building fabric did not contain materials that were particularly sensitive, a ventilation system was installed.
Thermal bridging was minimised by insulated dry lining, including the window and door reveals. Counter-battening was used in the roof and care was taken over insulation edge details at ground floor level.
Daylight was provided to all habitable rooms. Roof lights were added to the courtyard in-fill (the main dining room) - this area had been an external space between the two houses and was filled in to create a new, light and airy room in the centre of the home. Architecturally, this room was treated differently, an 'external' feel being given to the decoration with earth plaster walls and a slate floor which is linked to but separated from the slate patio area in the garden.
The new dining/family room faces south into the garden and has a glazed facade and rooflights.
Natural passive stack ventilation has been installed with humidity controls.
A wood burner is located in the centre of the building with an external air feed and a shut-off valve. A high efficiency gas condensing boiler supplies an underfloor heating system on the ground floor and radiators upstairs. Room thermostats, radiators with thermostatic radiator valves (TRVs) and weather compensation controls have been included. A solar collector connection is planned for the future.
Low energy light fittings are used throughout together with low energy appliances.