DOORS AND WINDOWS
Barker Shorten Architects’ sliding glass door for an east London penthouse
Barker Shorten Architects has conjured up a vast sliding glass door for maximum visibility at a penthouse in Limehouse’s Ratcliff Wharf
Architect Barker Shorten Architects
Location Limehouse, London E14
In these lean times, to be in possession of good persuasion skills can come in handy.
Jaimie Shorten, partner of Barker Shorten Architects, first visited the owner of a penthouse apartment to discuss a modest proposal to create a small balcony to the rear of the property. Shorten went away having convinced him to do a considerably more ambitious scheme.
The escalation in ambition must have been aided by the building’s location, just south of Limehouse Basin in east London and right on the Thames’s north bank, with a stunning river view from the building’s rear. The apartment occupies the top two storeys of a four-storey building. Constructed in 1959, it still had its original steel-framed Crittall windows on the second floor, but the space on this floor was “very frontal” says Shorten, and didn’t make the most of its majestic view at the back. Shorten suggested the removal of these windows and brick piers, and the insertion of a massive, bespoke, motorised sliding door, 4.2m wide x 2.7m tall, which Shorten believes could be the biggest insulated sliding door for a domestic property in the UK.
The existing floor didn’t make the most of the majestic view of the Thames at the back
The original plan to create a new balcony was still carried out, the balcony leading off the new sliding door and featuring a 1.1m-tall frameless glass balustrade with a teak handrail. An existing Crittall window at the eastern end was also replaced with a clear paned and fixed window within the existing opening.
The proposal also involved the removal of a semi-circular balcony at the western end of the second floor space and the creation of a winter garden, a glazed-in balcony which incorporates a glass pass door to provide a second access to the balcony. A small casement window has been inserted to the other side of the winter garden to aid ventilation.
On the floor above, which was added in the 1980s, a new balustrade was added to the existing 4.6m-deep x 9m-wide terrace and a galvanised mild steel frame — which Shorten refers to as “the belvedere” — built over the back of the building to frame the view and provide partial shelter via its roof to the balcony below. The soffit to the 4m-wide x 2.7m-deep roof is supported on very slender (150mm-wide) 6.7m-long posts which sit on the outer edge of the second floor balcony. It is fixed with a mirrored, stainless steel sheet which reflects the movement and sparkle of the water.
To provide shade over the top floor terrace, two mild steel beams (260mm-deep and 90mm-wide channel sections) and spanning 11m without intermediate restraint, are fixed, to which stainless steel woven panels or sun shades sit and can be slid across manually using a Harken Battcar, a raising and lowering mechanism normally used in yachts. Depending on the amount of shade required, the sun shades can be moved back and forth, creating different configurations. Due to the exposed nature of the third floor terrace, an oak screen was also fixed to the existing steel structure at the western end to act as a windbreak.
The £333,000 project took about six months to complete — and in that time the team had to obtain a licence from the Port of London Authority in order to erect the scaffolding on the river beach, as well as check the tide timetable to ascertain the best time to assemble the scaffolding.
The work has transformed the space. “To change this frontal and enclosed feeling into a more open one that engages the viewer and allows more enjoyment from that sublime experience of being on the river has been achieved with this project,” says Shorten.
Original print headline - Ratcliff Wharf penthouse
Sliding motorised door
When the high-spec motorised sliding door was first mooted, architect Jaimie Shorten assumed that only a Swiss or German door manufacturer could make it. However, main contractor Gilby Construction had worked with Lincolnshire-based Door Technik on another project and recommended the firm.
1 Belvedere roof
2 Sliding screens
3 New balcony
4 Giant slider
Door Technik had a large workshop which enabled it
to construct over a period of three months a full-scale mock-up (8.4m wide x 3.7m tall) of the entire assembly. This was required mainly because a door of this size
had never been made by the company, and it was a test-bed for all the components except the glass — everything was tried out in it before being used in the final design.
The door itself comprises a 10mm toughened outer layer and a 12mm toughened and laminated inner layer with an argon-filled cavity between the two layers — the glass was supplied by Firman Glass and weighs a hefty 540kg.
The frames to the sliding door and windows were constructed from thermally insulated steel frames powdercoated with a textured architectural finish and fitted with multiple weather seals. The door frame itself was strengthened by inserting steel around its corners.
Graham White, Door Technik’s managing director, says: “Our brief was that we had to achieve an elegance of appearance and functionality suitable for a high-end apartment. Lines of sight were maximised, all steelwork had to be as slim and unobtrusive as possible, and fixings had to be hidden.”
To accommodate the sliding door and the winter garden
at the west corner, most of the brick wall that enclosed the second floor was removed — the client wanted as little of it left as possible. The terrace which lies immediately above was temporarily propped up while a new steel frame was inserted.
An entirely new separate steel frame replaces the support provided by the original brick wall underneath the terrace, carried on only one steel post at the corner of the winter garden. The steelwork that holds up the door track is hung from the 1980s steel beams that support the terrace.
Floor-mounted guide fins run in a groove in the bottom of the door to keep it upright.
A floor-mounted track for the door was avoided for visual reasons, and instead Door Technik installed isolated floor-mounted guide fins that run in a groove in the bottom of the door to keep it upright.
The installation of the heavy glass panel was a bit more problematic, especially as it broke during the first attempt at installation. The glass had to be craned over the building and inserted into the door frame using a glazing robot with suckers.
The door is operated by a hand-held remote control, while the mechanism is concealed within the ceiling. A geared motor drives a toothed rubber belt, and the door is suspended on an overhead track. The door slows down as it approaches the end, and is also wired to give “dead man” operation, which means the door will stop if the user takes his finger off the remote control button. White says that they had difficulty finding a track and powered door operator that was powerful enough and had the weigh-carrying capacity, but they were successful in the end.
To make the most of the view and to introduce another axis
to this view at the second floor, the architect suggested that the corner of the west wall, which had a semi-circular balcony, be removed and a fully glazed, frameless winter garden be inserted.
Second floor plan
2 Winter garden
3 Sliding door
4 Balcony door
5 Fixed window
Central Glass & Glazing supplied the full-height floor-
to-ceiling glass that sits in the channels to the top and bottom, and features a butted sealed joint. The glass is fixed, but a small, operable window (0.5m wide x 2.8m high) located in one corner of the winter garden can be opened to provide ventilation.
A glass-hinged pass door is also accessed from one side of the winter garden allowing the user on to the balcony.
Architect Barker Shorten Architects, Structural engineer Andrew C Smith, Main contractor Gilby Construction, Structural steelwork Playle Engineering, Glazing sliding door Door Technik, Fixed glazing Central Glass & Glazing, Sliding solar screens CF Baker, Solaris mesh Potter & Soar, Sliding mechanism (Battcars) Harken UK