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Welsh Slate is the “perfect application”

Welsh Slate is the lucid choice for Lucent.

 

A project that exemplifies a “perfect application of Welsh Slate to unify a unique roofscape,” has drawn to completion by Wates on a landmark site in London’s iconic West End.

Prior to its development, the triangular site at Piccadilly Circus was a mixture of 13 buildings of different ages, architectural styles, listings, ownerships and uses. But they are now brought together under a new Welsh Slate roof that in itself mimics the complex labyrinth below.

Fletcher Priest architects’ 144,000ft2 mixed-use scheme for Landsec’s Lucent, the new name for the city block that accommodates the Piccadilly Circus Lights, has been radical, involving rebuilding brick by brick and then vertically stretching some of the facades, creating pocket balconies and a three-storey basement, and tucking 20 south-facing rooftop terraces into the Welsh Slate roof that was deliberately facetted to preserve protected views.

To meet their ambitions, a mix of Welsh Slate’s County-grade 500mm x 300mm and 500mm x 250mm Cwt-y-Bugail Dark Blue Grey slates were laid over 1,750m2 on pitches ranging from 20° to 80° by EJ Roberts Roofing Contractors.

The almost vertical slating features on the Lucent entrance in a narrow frontage to a new infill building. It is one of the few areas of the now seven-storey elevations where the geometry of the new city block-sized roof is visible, another being on a replacement retail unit.

The structure of the roof covering the commercial/office, retail and residential elements of the scheme comprised a steel frame with insulated cassettes that were craned into position and then covered in underlay and counter battened ready for the Welsh slates to be nailed into position.

Project architect Joe Sweeney said: “It was a contextual decision to use Welsh Slate as it is appropriate for the building and the area. The roof is a very important part of the project as it unifies the 13 different buildings into one consolidated project.

“It was important to us to use local and traditional products and their sustainability was equally as important, so the Welsh Slate met all those requirements.”

 

Paschal Fennelly, estimator with EJ Roberts, who were 12 months on site, said: “The original design for the roof was a high-tech luminous curtain roof screen but the planners and conservation officers stepped in to insist that all new pitched roofs were done in new Welsh Slate as some of the retained sections of the building and facades had listed status.

 

“The Lucent building is right on top of Piccadilly Circus which presented many logistical challenges. It is estimated that more than 100 million people visit Piccadilly Circus every year. On average, this means 8.3 million people every month, and two million people every week. You can imagine that trying to build in that ultra-busy environment is very challenging.

“Whilst we had no curved roofs, we certainly had plenty of multi-faceted roof slopes. We used zinc capping and valley details to weather the junctions, strengthened by galvanised steel lining sections. The same application of zinc with the galvanised steel was used for all weathering details relating to the new Welsh Slate roof.”

Paschal added: “It was one of the most challenging contracts ever for our company, in terms of restrictions on traffic and parking, waiting times for the crane to get the materials to the roof, controlling the loading zones, staying safe, protecting the public, controlling the hoisting activities, working at height, the risk management of Health and Safety requirements, quality management systems – all that takes up so much energy and management time.

“But this roof is probably a perfect application of Welsh Slate to unify a unique roofscape – an excellent roof design and a new Welsh Slate with top-class roofers equals a great roof.

“I would like to say that the real key to the success of this project is down to our directors Emerson Bennett and Dean Skipper, aided by our site surveyor James Wallace. They worked hard to drive this job and deliver it on time and on budget. We are also blessed to have great roofers who delivered the best standards of workmanship, and of course, the star of the show is the new Welsh Slate.”

 

Fletcher Priest’s project book says of the roofscape algorithm: “The algorithm for the design of the roof is generated by the pedestrian experience of walking around the building. Anyone standing on the opposite pavement of the surrounding streets should not be aware of any of the roof penetrating the skyline when looking up at the eaves. This results in an unusual but functional roof geometry, with the lowest angles generated becoming terraces.

“There are planning constraints around the viewing corridor to Westminster Palace from Primrose Hill, which is a statutory view needing to be maintained. Even though there have been viewing breaches [by others], the building at Piccadilly Circus does not exceed the permitted height limits.

“Conceptually, the roof is the key unifying element of the whole building, bringing together its diverse facades and levels, and touching down towards the ground with a flourish at the former Rainbow Corner and Sherwood Street entrance.

“The design may be an exercise in how to hide the roof from the street but it would be photographed or filmed from above, so the roof’s sculptural quality is important. When seen from above, the roof becomes the fifth elevation. Piccadilly Circus has to be one of the most popular locations in the UK for aerial shots for use in movies, video game, advertising and print publications.”

And of the 3D slate roof, it says: “The slate roof design fits within the context of historic Westminster, as does the inclusion of traditional mansard roofs. Working through the various facets of the roof with the structural engineers required 3D modelling to turn sometimes irrational shapes generated by the street-view algorithm into buildable forms.

The roof has been designed using modular systems – cassettes which are manufactured offsite then dropped into place on the building, with roof slates subsequently applied. Charlie Scott, the structural engineer, described it as a modern way of designing a tiled roof, as the geometry requires interesting structural design, and he doubts if it could have been done without BIM. The process is much simpler with a 3D virtual model, as it’s possible to test every awkward interface and precisely set out the steelwork underneath.

“Alongside the modern construction techniques for the triangulated and faceted roof structures made offsite, the mansard roofs above the historic facades are built on-site using timber – an environmentally sustainable material for roof making. Warren Alexander-Pye [project director at Landsec] describes using a traditional roof material like slate on geometrically challenging roof shapes, and then having to squeeze gutters and drainpipes into the gaps. He describes the result as super-sharp, giving the building an identity when seen up above.”

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Welsh Slate’s Cambrian slate wins international recognition

Cambrian Slate has been awarded Global Heritage Stone Resource status.

Cambrian-age Welsh slate, which is produced at Welsh Slate Ltd’s Penrhyn quarry in North Wales, has become the first slate in the world to be designated a Global Heritage Stone Resource (GHSR).

Its designation by the International Union of Geological Sciences (IUGS), which represents the national geological societies of 121 countries, recognises its importance to the architectural heritage of the many countries in which it has been used in the past and continues to be used today.

It easily met the prestigious GHSR criteria of having a cultural history encompassing a significant period, been utilised in significant works, and widely used in numerous countries.

Cambrian Welsh Slate has been quarried in Wales for almost 2,000 years (its first use being recorded in Roman times), has been utilised on major heritage projects, and been used throughout the world, particularly Australia, New Zealand, America, the West Indies, Europe and even Hawaii.

It was proposed for GHSR two years ago by the Welsh Stone Forum supported by the Stone Roofing Association (SRA), Gwynedd County Council, the Snowdonia National Park Authority and Welsh Slate (Ltd) at the same time as the Welsh slate industry is being proposed as a World Heritage Site.

Designation was awarded by the international Heritage Stone Task Group (HSTG) of the IUGS which was formed to safeguard natural stone heritage by establishing, approving and maintaining the new international geological designation – the GHSR and associated Global Heritage Stone Province (GHSP).

The Cambrian slate belt in Gwynedd extends over 14 kilometres and was historically quarried in three main areas although it is currently only extracted at Welsh Slate’s Penrhyn quarry in Bethesda where it is produced for roofing, architectural (cladding, flooring, paving and walling) and a variety of crushed slate products.

Natural slate expert Terry Hughes, former technical manager with Welsh Slate and chairman of the SRA, said: “We were a supporter of the GHSR concept from its inception. It has been a long haul writing the proposal at the same time as the designation scheme was being developed. We are now delighted that the importance of quarrying and the continued production of Welsh Slate especially, has been recognised. All too often the public forget that almost everything they use which isn’t a plant probably came out of the ground.”

The IUGS explained: “Natural stone rarely excites major interest despite the fact it has been used for construction and other purposes for thousands of years and is part of human tradition. Yet natural stone is also the world’s most sustainable mineral resource because it requires less energy to utilise, produces no toxic by-products, and provides the earth’s most durable construction material. So natural stone should create more than passing curiosity.”

Cambrian Welsh Slate has been used on Buckingham Palace, the Royal Pavilion in Brighton and the British Library in the UK; The Royal House, Copenhagen, Hotel de Ville, Paris and Dublin Castle in Europe; the Shaker Museum and Boston airport in America, Christchurch Arts Centre in New Zealand, and Government House [Perth, pictured] and Sydney Supreme Court in Australia.

Welsh Slate’s commercial director Michael Hallé said: “This is international recognition of the importance of the slate produced from the Cambrian stone in Penrhyn and is important for heritage buildings all around the world.”

GHSR designation seeks international recognition of natural stone resources that have achieved widespread utilisation in human culture. It aims to promote greater prominence for natural stone as used in artistic and architectural masterpieces and heritage building as well as routine historic stone applications.

Designation will also enhance recognition of natural stone among geologists, engineers, architects, heritage professionals, stone industry managers and other groups that work with stone. It will also offer a mechanism to formalise the characteristics of natural stone material for professional purposes and assist international co-operation into the research and utilisation of natural stone.

http://media.globalheritagestone.com/2018/12/Hughesetal2016.pdf

For more information visit www.welshslate.com
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Welsh Slate turns itself inside out

UK’s leading manufacturer launches brochures for interior and exterior uses.

New coffee table-style brochures showcasing Welsh Slate products for interior as well as exterior applications have been launched by the leading UK manufacturer.

Available through www.welshslate.com, the eight-page brochures dispel the myth once and for all that Welsh Slate, part of the Breedon Group, is just about roofing, with stunning photographs proving the product’s versatility for a wide range of uses.

Both beautifully illustrated brochures talk briefly about the company’s quarries in North Wales, including Penrhyn at Bethesda and Cwt-y-Bugail in Llan Ffestiniog, being a focal point for the production of UK natural stone for the past 700 years – the slate’s 500 million-year-old pedigree is reflected in the fact it is still handcrafted.

Although both show the range of colours (Penrhyn Heather Blue and Grey and Cwt-y-Bugail Dark Blue Grey) and finishes (riven, honed, flamed and machined) there the similarity ends.

The exteriors brochure features copings and sills, as used at the ME Hotel in London, walling and cladding as used at the National Waterfront Museum and many prestige private properties, paving, and roofing as used at York Racecourse and St Mary Abbots Church, London.

The interiors brochure features flooring, as used at the British Museum, interior walling and cladding, worktops, and fire and hearth surrounds.

No matter inside or out, the brochures reinforce Welsh Slate’s suitability for a wide range of contemporary and heritage architectural and interior design uses due to its aesthetics, durability and low maintenance.

For more information please visit www.welshslate.com.
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Welsh Slate is trusted to help deliver a medieval facelift

Roofing, walling and flooring from Welsh Slate feature on the redeveloped cardigan castle.

A three-pronged helping hand from Welsh Slate has contributed towards giving a medieval castle a new lease of life.

The manufacturer’s roof slates, walling and floor tiles feature on multiple aspects of the £12.5 million redevelopment of Cardigan Castle which had been in danger of being lost to the nation forever.

Penrhyn Heather Blue slates from Welsh Slate’s quarry at Bethesda have been used to re-roof Castle Green House, Ty Castell and The Stables while 200m2 of dark blue grey cleaved walling from the company’s Cwt-y-Bugail quarry clads the interior and exterior walls of “1176” – a new 70-cover contemporary restaurant which cantilevers over the castle walls.

Here the coursed walling is complemented by Welsh Slate’s Cwt-y-Bugail Dark Blue Grey floor tiles which are echoed in a total of nine new bathrooms in the East Wing guest accommodation and Green Street Cottages visitor centre. The new Welsh Slate flooring was laid by main contractor Andrew Scott of Port Talbot.

The Welsh Slate materials were specified by Purcell architects who worked for 10 years to repair and regenerate the 13th Century site, albeit with a few modern money-making twists.
Project architect Izaak Hudson said: “Cardigan Castle is one of the most significant historic building projects recently completed in Wales and all of the project team were very keen to be able to use local materials where we could.

“We specified Welsh Slate to match the existing slate on site, with WEFO*1 funding targeted at Welsh materials and contractors, but also because it was historically appropriate and good quality.”

“Castle Green House, the main dwelling within the castle walls, has a large-format, wet-laid diminishing course roof. This was expertly re-laid by skilled roofers from Tree and Sons of Milford Haven. The wet laying took some time as due to the weight of the huge Penrhyn slates we had to wait for the lime mortar of lower courses to carbonate before laying more, but it was a key existing feature and Cadw were very keen to reinstate it.”

Home to the first recorded Eisteddfod in 1176 (hence the restaurant’s name), the castle was partly dismantled by Cromwell’s forces after the Civil War, then enjoyed a brief renaissance in the early 19th Century as a Romantic site for a new mansion.

By the end of the 20th Century the site was derelict and ruinous, its buildings collapsing and roofs open to the weather. Most noticeably, the castle curtain walls were propped up with great raking shores to prevent their collapse onto the town’s main road.

This was despite the castle’s designation as a Scheduled Ancient Monument and the six buildings within its walls being listed Grade II or Grade II*. So under public pressure, Ceredigion County Council acquired the site from the elderly owner while a group of local people set up the Cadwgan Trust to help.

Purcell architects were commissioned in 2005 to carry out an options appraisal to identify future potential uses which were agreed as heritage interpretation, a restaurant, holiday accommodation, restored gardens and space for open air events.

Phase I of its redevelopment was the £1 million repair of the castle’s curtain walls; Phase II was the conservation and upgrading of the six buildings within the castle walls and restoration of the Regency gardens.

The conservation works covered all aspects of traditional building skills, ranging from structural carpentry repairs, to slate roofing, leadwork, masonry repairs, external joinery repairs and lime rendering.

Purcell carried out careful research, along with trials and testing of materials and finishes, to inform its conservation decisions and ensure the building would be an exemplar for innovative conservation practice.

The project brief required new accommodation to house the restaurant and catering facilities and the decision was taken to locate the new building above a section of the castle walls which had collapsed in the 1970s.

The position provides views across the Teifi quayside and the river below and inwards across the castle Regency gardens. Purcell’s design cantilevers out above the castle walls, its strong visual presence indicating to visitors there is something special inside.

The new restaurant is uncompromisingly contemporary with large glazed elevations taking advantage of the views and giving it a transparency which helps minimise its impact on the site. Where solid, the external and internal walls were constructed of coursed Welsh Slate laid by Coe Stone of Carmarthen, specialist stonemasons concentrating on the conservation and repair of historic buildings and monuments, echoing the Cilgerran slate garden walls that form the backdrop to the site.

“It was a very challenging and interesting project and we learned a lot about slate,” said Izaak.

*1The Welsh Government organisation distributing funds from the European Union for economic and social development.

For more information please visit www.welshslate.com.
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