A timber oasis

Sheppard Robson’s timber pavilion created in Manchester’s Spinningfields commercial district offers a contrasting distraction, with an exposed frame and richly textured elevations harking back to colonial buildings. James Parker reports

Spinningfields is Manchester’s biggest commercial district, home to a clutch of new glass and steel buildings housing finance firms and many of the city’s more prestigious bars and restaurants as well as retail names. Pristine offices – including in Hardman Square which forms part of the development, contain workers ready to enjoy the new quarter’s amenities.

One of the popular establishments for a high-end crowd is the Ivy restaurant, located in an eye-catching timber building in the centre of Hardman Square. The rectilinear double-cantilevered pavilion’s form, by architects Sheppard Robson (SR), is offset by a softer, more richly textured exterior that presents an intriguing contrast with the commercial units surrounding it. Its distinctive ‘colonial’ appearance befits the classically British Ivy brand established in London, and now present in several UK cities.

The practice has had a long-standing presence at this location, and a close relationship with client developer Allied London, having worked on the 3 Hardman Square office buxfilding before the 2008 recession, among other buildings. The cornerstone of the development, No. 1 Spinningfields Square, grew from an original refurb proposal by Ian Simpson Architects, with Sheppard Robson being finally appointed to deliver a landmark glass and steel building.

While SR were working on that scheme, the client approached them, says partner Neal Allen-Burt, regarding a plot between numbers 1 and 3 Hardman Street. It was occupied by a temporary single-storey pop-up restaurant (The Lawn Club), and Allied London asked the architects to develop proposals for a pavilion.

While this would be a relatively small (1,150 m²) building for Sheppard Robson, Allen-Burt also characterises it also as a signal by the client Allied London that Spinningfields “was growing up a bit.” So rather than the more informal dining which previously took place on the site, food retail was “becoming a bit more sophisticated, linen and napkins rather than scaffolding planks on breeze blocks.”

The building would also be a catalyst for the completion of Hardman Square as “the final piece in the jigsaw of Spinningfields,” says Allen-Burt. The practice developed “loose” ideas of a richly green public realm, however its design would be developed by landscaping architects Layer Landscape. The pavilion would be closely linked with its surroundings, with its elevations effectively “wrapped in a veil of landscaping, so the architects “were looking to closely align the two concepts.” The proposal also included two smaller buildings within the public realm (the ‘barn’ and the ‘cabin’), and although these did not end up getting built quite as planned, two pop-up timber kiosks have been erected in their place.

At the project’s outset, the final tenant was not confirmed; Allied was considering multiple restaurant operators, or a series of pop-ups. However, requiring a Manchester location for its brand, the Ivy came out on top of a range of possibles, widening the goalposts somewhat once the initial scheme had gone through planning. “The Ivy came back and said it’s great, but we want more space,” says Allen-Burt.” What was to be a more modest two-storey pavilion is now three stories, plus a roof terrace.

The four-storey Ivy restaurant is a permanent venue, albeit only designed for a 25-30 year life, rather than a more common 60 years. Partly inspired by the temporary timber buildings in the square, the exposed glulam frame is based on a regular 6 metre grid pattern formed of 280 mm deep structural elements that are expressed externally. The structure is clearly revealed so that a viewer can understand the building’s floor plates and columns from a quick glance at the exterior.

A grey-painted diagrid of steel bracing sits proud of the timber grid, forming the next layer of the relatively complex facades, largely following Allen-Burt’s initial concept sketch. This structure, which needed to be in steel as timber members would have been “huge,” makes it possible to create 6 metre cantilevers in the structural bays at either end of the building. These deliver the quantum of necessary floor area for the Ivy, while dealing with the issue of building above existing basements beneath Hardman Square. They also provide more visual interest, and provide a canopy and sense of arrival to the main entrance at the northern end, where the building faces onto the approaches into the square.

The designers wanted to “make a virtue” of this strongly expressed diagonal structure, and the cantilevers, which echo other Sheppard Robson buildings in the area (3 Hardman Street, and 1, the Avenue, which is tenanted by Armani, and has a 27 metre cantilever). Allen-Burt says that in designing an exposed external structure, it’s important to “work very closely” with the structural engineers (in this case Engenuiti), otherwise the facade can “become a structural solution rather than an architectural one.”

The building has no front or back, being ‘very much an island,” and addressing this challenge fed into the notion of creating a trellis-like exposed frame to make a visual statement; the decision to give it “more of a colonial feel” as a pavilion, redolent of buildings in the Far East, was driven by the client, says Allen-Burt, but the practice’s key ambition to expose the timber, and solve how it would weather, was a challenge. “When we first pitched the idea, I remember saying to their chief executive, I don’t know whether we can build this yet. We’ve done lots of timber buildings, but not quite like this. But they were extremely supportive.”

The idea behind the 700 mm deep multi-layered facade was to “contrast with the surrounding buildings, which are largely single skin with small amounts of solar shading,” says Allen-Burt.

The horizontal and vertical exposed larch glulam elements provide a good amount of shading, but the architects wanted to enhance this, while also facilitating landscape growing up and across the building. So a metal trellis was designed, in front of the darkened timber cladding, with further timber slats positioned within it. Onto this structure is mounted GRP planters with laser cut anodised aluminum faces, which sit on the projecting floor edges. This enables a high volume of planting to combine with the trellis as the final visual layer of the facade, producing bands of green running across the building. There are also gabion boxes hanging underneath floor ledges for “trailing and hanging” plants, and a mesh between the trellis members for climbing plants.

As well as offering further shading in summer months, the landscaping will provide “some disorder to what are very rigorous, ordered facades,” says the architect, “as if it started to overgrow the building.” To complement the natural feel, the architects wanted to avoid overt symmetry; which, with the building being eight structural bays long, was a risk. The flexibility provided by the multi-layered facade was exploited to both adjust to the changing window placements as the tenant decided on its internal arrangement, but also to offset the facade elements from the windows so that the metal meshes and timber louvres don’t line up precisely with the windows behind them. This disrupts any impression of the building being too orderly that might have resulted from what is a fairly simple underlying structure.

Interiors & roof terrace
The ground floor contains the Ivy Brasserie, with the first floor housing the ‘Dalton Room’ for private dining, kitchens and staff areas. The second floor has the Ivy Asia late-night bar and restaurant, complete with a bright green, illuminated stone floor. The Roof Garden is a separate restaurant, on an enclosed terrace added to the building’s three storeys.

The architects wanted the roof to have a considered design, as a “fifth elevation that’s looked down on,” and the final solution came late in the day. The architects suggested including a glazed, metal ‘orangery’ structure sitting within a timber trellis, “It was very important to me to keep it as honest to the original idea as possible.” The semi-external space has a retractable roof, but also has two canvas ‘boxes’ at either end, providing further dining space required by the client.

CLT & glulam
The ‘stick’ glulam frame consists of columns and beams, on which sit 140 mm CLT floor slabs, supported by ribs. Due to this construction by manufacturer Stora Enso, the thickness of floor slabs can be reduced considerably, in this case to match the exposed external glulam beams. In addition, floor to ceiling heights are maximised, and a lighter weight overall structure is produced.

Thanks to the structural engineers suggesting this approach, the alternative of a “potential 200 mm thick CLT panel to span 6 metres was avoided,” says Allen-Burt. He adds that it’s “potentially a more stable structure, as it’s deeper overall when the glulam ribs are taken into account.

There were compromises when it came to the interior of the building and the question of exposing the CLT panel walls, due to the client’s desires for their own distinctive decor. Says Allen-Burt, “we worked very hard to disguise all the bracketry, but when the Ivy came on board they covered everything up.” Despite the diagonal metal bracing, this is largely a timber building; the lift and stair cores are CLT, as well as stair treads and risers.

Another benefit of going for timber wherever possible, supported by the contractor BAM, was that subcontractors on site were minimised. The architects and contractors decided to maximise efficiency by allowing all of the trade packages that did exist to be “effectively subcontractor designed.” Allen-Burt explains: “We took our design up to a very detailed phase 3, but ultimately most of the elements other than the frame itself were designed and detailed further with the subcontractors.

“It was a very collaborative process, rather than traditional D&B jobs where you put forward a design intent, something else comes along, and doesn’t quite work or coordinate.” Allen-Burt adds: “It actually helped us to resolve complicated interfaces.”

As part of the drive to minimise packages, Allen-Burt pushed for a CLT screen to be included around chillers and boilers in the roof. An unintended benefit of this occurred when the restaurant suffered a small fire on the roof terrace three months after it opened, despite significant damage that meant the glass and steel enclosure had to be replaced, the restaurant levels below were able to resume operation within 24 hours, partly because the fire charred the CLT wall, but it didn’t spread to the plant room.”

The idea for a ‘field’ in the square to provide an oasis for office employees and others “came from Allied London,” says Allen-Burt, adding that they are “very good at creating narratives for places and weaving them into developments.” The concept developed by landscape architect Layer reflects the local history, there having been a garden nearby.

Working with Sheppard Robson, they developed ideas of “field edges, meadows, woodlands – an existing group of trees further down in the public realm would be retained.” The two kiosks in the square tie in with “ideas of timber shacks in woods and fields,” and the landscaping scheme “tapers down from the woodland into the ‘field edge’ and more rough cut areas, into a ‘meadow.’” Finally there are more lawned areas with hard landscaping, adjacent to the new building.

This modest scheme, by Sheppard Robson’s standards, demonstrates what the architects can do to create a carefully textural timber building, and one which stretched their proven abilities into new areas. Having shifted somewhat from its original concept, its low pavilion form still adds a sense of welcome relief to a commercial district which exhibits the familiar glass and steel materiality of many of its counterparts.

Costing only £5m, the building represented a different challenge for Sheppard Robson, given the amount of design time and effort it would require. However it’s a “career highlight” for Neal Allen-Burt, who adds: “It’s not often we get a chance to do something like this.” The results of a somewhat experimental approach to using timber are bearing fruit: “Some of the ideas on it we have developed on the project are starting to inform ideas of how we may use timber on other buildings in the future.”

Project FactFile
Client: Allied London
Architect: Sheppard Robson
Tenant: The Ivy
Main contractor: BAM
Structural engineer (superstructure): Engenuiti
Structural engineer (substructure): RoC Consulting
Floor area: 1,150 m²
Landscape architect: Layer (Landscape Architecture)
Timber frame: B&K Structures
CLT & glulam manufacturer: Stora Enso