Initial proposals to convert this house from two to three floors were rejected way back in 2001 by the local Planning Department on the grounds of it being “visually intrusive, overbearing massing not part of the existing architectural language and overlooking neighbours”. These same considerations faced Robinson Leigh Architects, whose track record of successful planning application had led to their appointment in 2013 by a client keen to find a solution to the planning impasse.
There were a number of challenges for the architects, as they sought to design a scheme that would prove more successful through planning. The house is situated in St John’s Wood Conservation area, where restrictions on the character and appearance of all buildings are strictly applied. Normally any roof extension in this area would not be permitted and the house, indeed the entire mews, had been identified as an “unlisted building of merit”. Consequently the planners insisted that all new work to the house “must match existing original work in terms of choice of materials, method of construction and finished appearance”(1) in order to maintain the cohesion of the mews.
In conjunction with these structural requirements imposed on Robinson Leigh’s design of the mansard roof, unlocking natural daylight in the “dark zones” in the interior of the new storey was a key priority. Mindful of the rejection of the glazed roof proposal from 2001, which the planners had deemed to be too intrusive on the neighbours and at odds with the surrounding architecture, the architects sought to reduce the amount glazed by 50%, whilst simultaneously addressing the problem of reduced levels of natural daylight resulting from the recessed dormer windows.
Glazing Vision’s sliding over fixed skylight was to inhabit the space immediately above the stairwell, which had also been lined in timber to subtly link the top floor with the ground floor and to help draw the eye upwards. Timber frames had also been used on the windows. As with the other four skylights, Glazing Vision’s sliding over fixed skylight needed to be made to a bespoke size – the architects required it to be the exact size of the stairwell, or indeed over-sized, so that the frames were not visible from below. Precision-engineered at the Glazing Vision factory in Norfolk, the special sliding over fixed skylight was supplied in two sections, with an overall span of 2400mm and a width of 2240mm. The minimalist internal framework, finished in pure white rather than the standard grey, ensured that there were unfettered, sky-only views from the inside, thereby enhancing the impression of space and loft. Through the clear glazing of the Glazing Vision skylight natural daylight absolutely flooded the stairwell, permeating also down to the lower floors.
No less important was the need for natural ventilation in the mansard roof extension. The architects were keen to create a venturi effect in the central core of the house and stairwell by channeling the airflow through the opening of the skylight. The Glazing Vision skylight, specified by Robinson Leigh to slide side-to-side rather than up and down, is electronically controlled at the touch of a button from inside the house, retracting the sliding section over the fixed section of glazing. Once the sliding section is fully retracted, there is a 50% clear opening in the skylight, out towards the sky, thus providing superior air quality within the top floor, as well as intensifying the amount of natural daylight. An essential security feature of the Glazing Vision sliding-over fixed skylight is that it is supplied with a manual override as standard.
If you would like to discuss design considerations for an upcoming project, call Glazing Vision on 833-759-3667
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