Extension & Refurbishment


470 m²



Originally, this 1970s house in the leafy suburbs of Cardiff was intended as part of a development of three similar properties. Each house with a long/narrow plan form to fit within the constraints of the site. However, only two houses were built but the narrow plan form was retained. The result was a house pushed to one side of a generous plot with a long narrow garden running alongside. This elongated effect was compounded by the garage being located at the back of the plot with the driveway having to run almost the entire length of the garden. Having not long bought the property, our clients approached us wanting to extend and refurbish the house. They could also see the potential to make better use of the plot.

Initially, a concept design was developed in collaboration with our client. It was agreed that the original garage would be demolished. The new garage positioned just shy of the front of the house but set apart to distinguish the new entrance. This new layout also helped to create a much bigger garden to the rear with the shortened driveway freeing up additional green space. The gap created between the existing house and the new garage forms a double height lobby. Upstairs, a bridge spans over the lobby to link the original stairway with the new master bedroom. Most of the glazing to the lobby is along the northern side (with views of the rear garden). This aspect also helped alleviate the need for louvers or solar control glazing. The southern (entrance) side is partially glazed with a solid door and window above to give a view from the bridge down the driveway.

The existing house has also been extensively altered and refurbished. A significant component in this was the inclusion of much improved thermal insulation to the external walls and within the roof space. Areas of underfloor heating also gave us an opportunity to insulate the floors. In terms of materials, the main house has been re-rendered (the client had a particular dislike of the stone cladding). The ground floor of the extension is in brickwork to contrast with the original house and indicate the utilitarian nature of the garage. The first floor bedroom is clad in charred timber – a nod to the existing bay window at the front of the house. The naturally preserving benefits of the charring process and the low maintenance of the brickwork also appealed to our clients. The new bedroom is a well insulated box which overhangs the garage to emphasise the change of material and the different geometry. This also gave an opportunity to conceal strip lighting underneath the overhang. Both the brickwork and charred timber continues internally to help clearly define the two forms.

For this project, Kotzmuth Williams carried out a full service from initially developing a brief with the client through to construction and handover (with the RIBA suite of appointment documents and contracts). For the most part, this process went smoothly with a supportive client and planning department. There were challenges on site with the start of the build coinciding with the first Covid lockdown. Both our clients are healthcare professionals. A phased construction program was developed with the builder to minimise disruption. Perseverance by the builders and patience by our clients meant that supply chain issues during this time didn’t become a significant problem. The project was completed in early 2021. Since then, we have been in regular contact with our clients to get feedback and see them settling into their new home.