We were recently given the complex task of replacing these unusual ‘bottle top’ shaped timber casement windows on a listed property in Kingston, South West London.
Our client wanted to improve the insulation of the property by changing from single glazing to double glazing, without affecting the unique look of these unusual casement windows.
Although the single glazed windows that we were replacing weren’t the original windows, we needed to ensure that our replacement timber windows were faithful to the design of the existing ones to gain planning approval from conservation officers at the Royal Borough of Kingston-upon-Thames planning authority.
All the casement windows on this unusual property were different sizes so careful, accurate drawings were needed from our design team.
As well as the unusual shape of some of the windows, each window needed to include pre-antique lead bars. We used our slimmest ‘4/4/4’ slimline double glazing, to give the impression of single glazing while improving the insulation of the windows. Each window was glazed with putty, as it would have been when the windows were originally made.
To further improve the thermal efficiency of the windows, each one was fully weather stripped with compression seals – which are more thermally efficient than regular brush seals. We also chose Accoya timber for the windows as it is not only an incredibly durable and stable timber, it is also thermally efficient.
The casement windows were finished with traditional black ‘Monkey Tail’ casement stays and fasteners, and a dual colour paint finish for the curved windows at the front of the property, using our long lasting microporous paint.
We also replaced the back door and side door of the property to the same specification as the casement windows, glazed with individual slimline double glazed units, glazed with putty and lead bars. See the gallery below for the full range of images.
We were pleased to discover that the Kingston-upon-Thames planning department were happy with the result.