CASE STUDY:UNISON House, London

The whole scheme achieved a 50% carbon reduction over and above Part L of the building regulations and having achieved a score of 73.5% was awarded a BREEAM rating of ‘Excellent’.

Squire & Partners Architects

As with any major building project in the capital, the construction of UNISON House threw up a series of challenges almost unique to the area. Not only was it almost ‘kerbside’ within one of London’s busiest thoroughfares but also close to the Royal National Throat Nose and Ear Hospital which tended to children with hearing problems. The foundations were also adjacent to various railway and underground services providing perhaps the more conventional impediments that London contractors take in their stride. The construction was also a regeneration project as the new building abuts the former Elizabeth Garrett Anderson Hospital which was opened in 1890 and being the first purpose built hospital devoted to the treatment of female patients by women doctors. Built within the lifetime of its founder the JM Brydon designed structure was Grade Two listed in 2003.

The brief from the client to its architects, Squire & Partners, was to design a campus type complex to provide a modern interactive facility for its workforce whilst also providing a building which will house its own TV and Radio Studios, Press Rooms, Conference Facilities and Council Debating Chamber. The sympathetic linking of these two very specific structures was always going to be the keystone within this design, as not only did it need to accentuate the Victorian features of the former hospital building but also provide a light and airy workspace that would not compromise the BREEAM or energy efficiency requirement aspirations of its clients.

The limestone clad columns and glass facade meant that the building was always going to be a prominent feature in the Euston Road but not only did it need to radiate good design principles, the construction was very much a working complex. The Atrium linking both buildings needed a great deal of specialist design input from MERO-SCHMIDLIN prior to construction. This is exactly the complex type of bespoke structure which they are known to specialise in. Whilst the requirements of the brief were challenging in many other respects, the roof had an aesthetic requirement as not only would it be viewed from below but with 4 further storeys of the new complex rising beyond the atrium, it would be viewed from above as well. The brief decreed that the roof should encompass a geometry which would include a series of triangular sections to represent the unions logo. The roof geometry with its meandering ridge had to interface with a range of different structure heights linking both the old former hospital and the new build offices.

MERO-SCHMIDLIN used their specialist design expertise to work with the main contractors and architects to develop the existing roof design. Concerns were raised by the MERO-SCHMIDLIN team with regards to both access for cleaning and possible ponding areas as the design included a number of glass panels with a very shallow fall. The possible ponding not only brings with it concerns over potential water ingress but also that the resulting residue could create areas where cleaning would be required more frequently

The expertise gained over many years both in designing and installing this type of roof was imperative and no doubt the experience gained from designing and installing the very complex roof systems on The Scottish Parliament Building and The Eden Project came to the fore. The revised design took into account possible weatherproofing issues on corners and secondary glazing consisting of 100 x 60 RHS members supported by Tee section rafters spanning from the Victorian facade to the new concrete framed structure. MERO-SCHMIDLIN’s specialist installation team put together a stainless steel tie rod support structure that ensured the Grade Two listed building bore no horizontal loading.

The entire roof and rear facade glazing features a flush silicone external jointing system with all glass panels and vents restrained using hidden toggle fixings laying on a fully ventilated and drained bearing gasket fitted directly onto secondary steelwork.

The building has since become a great success with the campus system resulting in staff who have worked for the union for many years ‘meeting each other’ for the first time in the atrium and adjoining cafe area.

The UNISON building is now a well known landmark on the Euston Road.

CASE STUDY: Roof & Glazed Rear Facade at UNISON House

PHONE: +44(0)1276 41 42 43 WWW.MERO-SCHMIDLIN.COM

The full extent of the complicated roof geometry is best appreciated when viewed from above

The MERO-SCHMIDLIN team in action installing the glazed roof

“The roof was fabricated in full in our fabrication facility in Boxberg, Germany. The steel frame was then cut into ladder frames and transported to the UK. The complete roof was then re-assembled in it’s final location with bolted connections.

Fabricating the roof in full in the factory ensured a high degree of accuracy in the setting out of the geometry, which for such a complex roof is vital. Members of our team, including the architect, visited the facilities to check the steelwork at the end of fabrication, just before the frame was cut.

The steelwork was then cut along pre-designed lines to create joints between the steelwork (the cut joints are only a couple of millimetres thick, the width of a thin cutting disk). After the cutting, local to each joint, plates were welded within the box sections along with accompanying csk holes, to form the bolted connections The connection details were designed so that only a thin joint was visible, with the fixings hidden under the glazing gasket. The bolted connection solution was chosen over welding due to ease of installation”

How MERO-SCHMIDLIN raised the roof

MERO-SCHMIDLIN (UK) PLC are able to call upon a great deal of design and installation expertise in the UK but this is further enhanced by their pan-european MERO network who have a huge portfolio of bespoke roofing and cladding projects in both Europe & Asia. These facilities enable MERO-SCHMIDLIN (UK) to tackle the most complex bespoke projects in a design only capacity or a full design, supply and install package.

MERO SCHMIDLIN (UK) Design Team Leader, Barnaby Howe explains the benefits that MSUK were able to offer on the UNISON building:

Offering engineered solutions for projects of this complexity is a hallmark of MERO-SCHMIDLIN (UK) PLC

MERO-SCHMIDLIN (UK) PLC‘Marlin’, 459 London RoadCamberley, Surrey GU15 3JAUnited Kingdom

Phone: +44(0)1276 41 42 43 Fax: +44(0)1276 41 42 41 Email: info@mero-schmidlin.com Web: www.mero-schmidlin.com

PHONE: +44(0)1276 41 42 43 WWW.MERO-SCHMIDLIN.COM

Scope of Works: Design, manufacture and installation of bespoke freeform glazed atrium roof and vertical façade with integrated opening vents

Cladding Details:

21m x 5.5m glazed façade, 39m x 12.5m glazed freeform roof (383m² surface area, comprising 326m² glass and 57m² opening aluminium clad vents)

Steelwork Details:

Spanning Trusses fabricated from mild steel 229x305x70 TUB with 24dia stainless rod rigging connected to a vertical 76 dia CHS compression strut. The Tee section supports a glazing frame of 100x60 RHS at approx 1.5m centres via 100mm long 33.7dia CHS posts. Roof structure factory welded in ladder arrangements comprising two adjacent trusses with glazing purlins welded between, these are site erected and purlins between adjacent ladder frames bolted into position via hidden connections.

Façade fabricated from 200x100 RHS for the outermost mullions and transoms at support levels, 120x60 RHS for all other façade mullions and transoms.

Contract Value: £1.7m