DLR Lexicon – Building an Icon

Like all iconic buildings, the DLR Lexicon (the name given to the new library in Dun Laoghaire) has attracted its share of controversy. Opened specially for an event on Culture Night 2014, controversy was forgotten for the most part as kids enjoyed the outside area while adults appreciated the stunning views from the fifth floor and the myriad spaces for people to escape with a good book.

Construction on the €36.6 million four-storey building began in May 2012, with completion reached in September 2014. Cork-based architects Carr Cotter & Naessens designed the building, John Sisk & Son built it and Horganlynch were the structural engineers. One of the first tasks for Sisk was to obtain a crane licence from CIE in order to allow the erection and operation of tower and crawler cranes.  CIE permission was conditional on the rail line being monitored for vibration, and restrictions on the construction and operation of the Tower Crane. “Alongside that, another initial job that had to be completed before work could begin was a sweep of the site for hazardous items such as needles, bottles and drink cans. The enabling works involved the dewatering of the existing pond and removal of the sludge. The sludge contained particular hazards which required the material to be dried on site and disposed of in an engineered landfill,” says Shane Glynn, Contracts Manager at Sisk.

Previously a well-known run-down park, home to lots of feral cats, DLR Lexicon sits on a fairly unique narrow site. It’s bounded by the DART, the Royal Marine Hotel and the National Maritime Museum of Ireland (a protected structure), so integration with boundary neighbours was a key consideration. “The granite bedrock was described as competent which was reflected on-site as extremely hard and unweathered. This competent rock was close to the foundation level, which allowed from a solution point of view an uncomplicated foundation structure to be designed,” says Karel Murphy, Horganlynch. Two methods were used to remove the rock – one method involved high impact breaking using 50 ton excavators with 6 ton hammers, while tougher rock was removed by an expansion grout technique which fractured the rock thus decreasing its strength significantly. Where rock was extremely hard, the hydraulic rock splitters were used. “Noise was certainly an issue during rock removal. We tried to suppress noise where possible. We endeavoured to restrict rock removal to the hours of 8:30am to 5:30pm weekdays and avoid breaking whilst key events were taking place in nearby venues.  Due to the irregularity of the rock, soil nailing techniques were utilised to support the embankments,” says Shane Glynn.

Reinforced concrete was the only material used for the structure of the Library. No blockwork, no structural steel – using just one material for such a large project isn’t the norm. “The finish of the concrete was very important to the project. As it would be visible in the finished building we had to take this into consideration when we were looking at the design,” says Karel Murphy. “When you’re dealing with one single material as the structural solution, obviously there are no difficulties interfacing with any other structural element but we did have specific design challenges while working with this concrete structural solution. We were dealing with the design of very large spans and extremely tall walls so we used finite element analysis for the majority of the analysis work on the building.”

“Externally approximately 6,500 sq m of Spanish granite was used; most slabs weighted over 115kgs with some slabs weighing up to 500kgs. Extensive quantities of European oak timber were used throughout the building to create bookcases, doors, acoustic panelling, flooring and furniture, much of which was produced in Sisk’s own Joinery works,” says Shane. The interior has been decorated in neutral tones of browns and blues while carpets and sofas are also in shades of blue, a conscious decision which allows colour to come from the books. When it came to joinery, Shane and the team at Sisk travelled to Denmark along with the architect and Truwood to select the trees to be used for the timber veneers. “The guy would wheel out a big log, sliced up like a loaf of bread and we’d sift through the veneers ensuring only the finest timber was incorporated into the works. After that, we got on a plane and flew to Italy where we selected all the solid timber for the project. The trees selected for the veneers were grown in Germany and the trees selected for the solid timber grew in Croatia. This isn’t standard practice for projects even of this size but does serve to demonstrate the extra lengths Sisk went to in order to maintain the highest possible standards of quality.  Environmental considerations were also a priority for Sisk and all joinery supplied was FSC certified. The building is largely naturally ventilated; stale air is drawn out and fresh air drawn in through “chimneys” capped by the cowls on the roof that look like funnels on a ship, an unintentional feature according to the architects.

Designed to offer a mix of both social and quieter intimate spaces, the structure was built into the existing slope creating two ground floor areas and a pair of quieter upper levels. One side is clad in granite (as a nod to the town’s former quarry) while the southern side is clad in brick (to respect the material palette of the Victorian high street). The roof is instantly recognisable, with nine ventilation cowls sitting on top. There are two entrances. One is accessed by walking in from the harbour and up along the side of the building and through the café while the main entrance is on Haigh Terrace, off Georges Street, through a revolving glass door. This entrance is located within a sheltered recess at the south-west corner, bringing visitors into a space described by the architects as a central ‘living room’ that looks out over the harbour. To the left of the stairs at the main entrance there are shelves displaying a collection of what’s available in the library and a place where people can read magazines, books or go online. To the right of the stairs is an automatic book sorter which will be able to receive books 24 hours a day. On the same level towards the seafront is a long art gallery with an audio-visual “mini-gallery” at the end of the room. A “Lexicon lab” with Apple Mac computers where young people and adults can make 3D graphic designs and a space for teenagers to use for different activities.

DLR-Lexicon-1The library will house about 80,000 items including books, CDs and DVDs for people to borrow. More than 50 mobile devices such as laptops, iPads, and Kindles will be available for people to use. As well as an adult and junior library, the building contains an auditorium, art gallery, café, and history department. At least four meeting rooms are available free to the community, each with a large table and wall-mounted 42-inch screens and for the first time ever, Dun Laoghaire will have a dedicated children’s library. A nice touch is a map of Dún Laoghaire is cast into the concrete in the far corner. The top floor houses a local history room for special collections, study and reading rooms and the office for the writer in residence and is very much being promoted as a celebration of local history and writers. The bottom floor, called Moran Park level, has a café with long windows looking out on to the park, the auditorium with 120 retractable seats, offices for staff and storage for about 40,000 items for all the libraries in the county. It’s hoped that this mix of facilities will attract more than 50,000 people to Dun Laoghaire every year.

A bamboo garden, a plaza lined with trees and a series of tiered water pools are dotted around the building’s perimeter. It is intended that the outdoor area will host free events, performances and market stalls. A bronze sculpture called Christ the King has been reconditioned and returned to the site and sits on a raised platform in Moran Park looking out towards the sea. Great care had to be taken by Sisk in the removal and remounting of this precious structure. Seating areas run along the edges of the space while a staircase at the heart of the library leads up to the main reading room on the level above. At the north-eastern tip of this floor, the huge two-storey-high window offers spectacular views out towards the Irish Sea. Throughout the interior, the building’s concrete shell is left exposed but is offset by the wooden floor and joinery that includes bookshelves and acoustic baffling.

According to Shane, one of the main challenges of the build was the execution of the high quality architectural concrete frame. “The zinc roof was very detailed and complex so that took time and careful attention to detail. The glazing incorporated bronze clad windows that required a bespoke design analysis and widespread sample production. A lot of research and time went into these elements to make sure we fulfilled the brief and maintained the high level of workmanship throughout. Good collaboration between the various sub-contractors and design team ensured the work was completed to the design intent.” As mentioned above, the library’s roof required a lot of attention. “The roof structure is interesting. There are 13 large ‘V’ beams which have spans of up to 20 metres and weigh up to 100tonnes, these clear span across the structure. The decision was made to make those in precast in terms of practicality and safety. They beams were produced in Banagher Concrete Co Offaly and travelled under license at night to get to the site as they were considered extraordinarily loads,” says Karel. Each roof beam is clad on one side by slatted oak acoustic panels and interspersed by parallel rooflights. “The beams lifts were certainly difficult. They required a tandem lift with two 2,500 ton cranes.”

Considerable time was spent on the design process before which meant the project required no major changes during the build. “It was well considered and well planned out from the start so we encountered no fundamental problems or changes. There was significant time given to the design which allowed us to achieve a considered solution,” says Karel.

Plans for such an ambitious project during a time of cutbacks were naturally considered controversial. But the criticism levelled at the project while under construction did seem excessive. “It’s completely understandable that no-one wants a building site on the main strip but there has to be an inconvenience to ultimately get what was achieved. There’s nothing attractive about seeing scaffold up around the structure. When it was peeled away and we were left with the building we now have, I think the attitude changed,” says Karel. Shane says the building probably doesn’t fit in with a conventional design for a library. “The truth is that most buildings that try and break the mould will endure some criticism. Some people have looked at it and revere its beauty and innovation while others loathe it. I really like the library’s interior, it’s extremely functional.”

According to Karel at Horganlynch, the primary consideration for them with DLR Lexicon was the fact that concrete was the only structural element used. “That wasn’t a limitation, it was the challenge and the result is elegant. The concrete form allows interesting spaces to be created. Now you can still admire and appreciate the primary structure which on other buildings is often hidden. With the new library, you’re looking at the structural shell. Internally there’s an honesty about how the structure is behaving.”

“A very high standard of workmanship has been achieved. Attention to detail has been second to none, driven by the architect and produced by the contractors. In general, the standards of quality that have been achieved by all teams on site are excellent. It’s important to remember that this was a very detailed and complex building. A huge amount of drawings reports and specifications had to be coordinated. It was a challenge but a very satisfying one,”says Shane.

 This article first appeared in Issue 1 2015 of Irish Building Magazine.

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