WELSH SLATE LTD

PENRHYN QUARRY
BETHESDA
BANGOR
GWYNEDD LL57 4YG

Tel: 01248 600656
Fax: 01248 601171

Company Logo

Suppliers of: Roofing slates, Slate cladding, Slate paving, Walling, Sills and copings, Landscaping, Aggregates, Slate tiles for flooring, Fire surrounds/hearths, worktops/counters

Welsh Slate Ltd is the world’s leading supplier of high quality slate and supplies the UK construction market with highly durable roofing slates, facade cladding, slate paving, walling, sills and copings.  For internal projects, Welsh Slate manufacture and supply slate tiles for flooring, fire surrounds, bespoke kitchen worktops and counters.

Environmentally Responsible

Welsh Slate’s Penrhyn quarry has been supplying slate worldwide since the 13th Century and has a long tradition of being specified by architects, and our client base also includes leading developers and interior designers. As a result of our work we are committed to conducting our business in an environmentally responsible manner by minimising the environmental impact and promoting sustainable development within its operations and services.

CPD Seminar

This seminar is designed to help architect and specifiers to understand the manufacturing process and the potential applications of Welsh Slate as a building material. It will explain the advantages and problems with slate and clarify the difference between differnent slates from around the world. The presentation will inform delegates of the variety of applications for Welsh Slate and provide information on the standards, accreditations, classifications and fixing methods.

CPD Factory Tour

The two hour tour will demonstrate the current slate quarrying and production processes while in addition giving you some hands on experience of working with a natural product. For enquiries or to arrange a CPD please telephone our sales office on the telephone number above or alternatively click here and fill out an enquiry form.

Our wide range of products include:

Roofing Slate

Welsh slate is proven to out last any other roofing material and is guaranteed to have a productive life in excess of 100 years. Colour variants are available and can be supplied up to 1.2 meters wide.

External Slate Paving

Welsh slate is available in a range of thicknesses from 30mm to 100mm and a variety of colours and textures to suit any application. Slate paving is frost-resistant and slip resistant certified to BS EN1341:2001

Welsh slate is weather and waterproof, unaffected by atmospheric pollution, sea air and organic growth and is colour-fast and non-fading, even in UV light. Certified and tested to BS EN 12326 - 1:2004

Welsh Slate Flooring

Welsh slate is a hard wearing natural floor tile for use in both domestic and commercial applications. The material is highly durable and easily maintained. As an unpolished floor tile Welsh slate is slip resistant to BS EN 1341:2001.

Facade Cladding & Masonry

Welsh slate facade cladding is ideal for use on either internal or external cladding products and is an ideal material for use on ventilated rainscreen cladding. Welsh slate masonry units are available in course heights of up to 180mm and to random or specified lengths with pillared or sawn face.

Our facade cladding is supplied to bespoke sizes and has been installed in diverse applications such as public buildings and churches to industrial and commercial developments and residential properties.

Stone Walling

Welsh slate makes an ideal walling product and is available as either quarried rustic walling with a naturally exposed face or as a smooth faced pillared walling face.

Sills & Copings

Welsh Slate can supply bespoke slate sills and copings for both refurbished and new-build commercial and residential properties and are available from stock and to order.

Aggregates and Landscaping

Slate aggregate has many outstanding technical properties. Welsh slate is available as a decorative aggregate in three colours. Our slate aggregate is also supplied for use in precast and ready-mixed concrete, road building and civil engineering.  Slate granules are used to produce bituminous roofing felts and artificial slate roofing tiles. We also supply Slate feature landscaping stones and monoliths.

Slate Fire Surrounds and Hearths

Welsh slate is the ideal stone for fire surrounds and hearths for solid fuel and wood burning stoves as well as open fires. Bespoke to your specific requirements, these fittings can be supplied in a range of colours, finishes and edge detail.

Slate Kitchen Worktops & Counters

Welsh Slate makes a beautiful and practical material for worktops and counters, combining very low liquid absorption levels with a luxurious warm feel to the hand.  The material is supplied as a completed wipe-clean slate worktop to consumers and contractors’ projects or as unfinished or polished scant to worktop manufacturers.

Further technical information, image galleries and product specifications are available through the Welsh Slate website or via the BPi Download Library.

ACCESS FLOORING Slate .
AGGREGATES Slate .
ARCHITECTURAL Stone Slate
CILLS Slate .
CILLS Slate Welsh Slate
CLADDING TILES Stone Slate
CLADDINGS EXTERNAL Cut Facing Stone Slate
CLADDINGS EXTERNAL Riven Slate Surface .
CLADDINGS EXTERNAL Slate .
CLADDINGS INTERNAL Riven Slate .
CLADDINGS INTERNAL Slate .
COPINGS Slate .
COPINGS Slate Welsh Slate
CRAZY PAVING Slate .
DRY STONE WALLING Slate .
FABRICATIONS Slate .
FIRE SURROUNDS . .
FIRE SURROUNDS Natural Stone Welsh Slate
FLAGSTONES Slate .
FLOORING Natural Stone Flooring .
FLOORING Natural Stone Flooring BS EN 12058 CE Marked
FLOORING Riven Slate .
FLOORING Slate Flooring .
HEARTHS AND BACK PANELS Welsh Slate Hearths .
KITCHEN WORKTOPS . .
KITCHEN WORKTOPS Curved Worksurfaces .
KITCHEN WORKTOPS Natural Stone .
KITCHEN WORKTOPS Slate Welsh Slate
LANDSCAPING Aggregates .
LANDSCAPING Paving .
PAVING SLABS Patio Natural Slate .
PAVING SLABS Riven Slate .
PAVING TILES Welsh Slate .
RAINSCREEN SYSTEMS Slate .
ROCKERY STONE Slate .
ROOF VENTILATORS Flush Slate .
ROOF VENTILATORS Welsh Slate Bat Access Units
ROOFING Slate .
ROOFING SLATES . .
ROOFING SLATES BS EN 12326 CE Marked
ROOFING SLATES Natural Stone .
ROOFING SLATES Natural Stone ASTM S1 Classified
ROOFING SLATES Natural Stone BS 5534
ROOFING SLATES Natural Stone BS EN 12326-1 CE Marked
ROOFING SLATES Natural Stone BS EN 12326-1:2004 A1-S1-T1
ROOFING SLATES Natural Stone Heavy Slate
ROOFING SLATES Natural Stone Heritage and Conservation Applications
ROOFING SLATES Natural Stone Heritage and Conservation Applications England
ROOFING SLATES Natural Stone Heritage and Conservation Applications Scotland
ROOFING SLATES Natural Stone Heritage and Conservation Applications Wales
ROOFING SLATES Natural Stone Low Pitch Roofs
ROOFING SLATES Natural Stone Welsh Slate
ROOFING SLATES Roof Weathering Slates .
ROOFING SLATES Strip Slates .
ROOFING SLATES Ventilator .
SLATE Paving .
SLATE Rustic .
STONE FLOORING See Also FLOORING: Natural Stone Flooring .
TILES, FLOOR Riven Slate .
TILES, FLOOR Slate .
TILES, WALL Slate .
WALLING Riven Face .
WALLING Sawn Face .
WALLING Slate .
WALLING Slate Pillared Slate
WALLING Slate Welsh Slate
WINDOW SILLS See Also CILLS: .
WORKTOPS Welsh Slate .

Welsh Slate products help strike the balance between design and crime

September 2019

Architectural products feature on the new HQ of an international crime agency.

Natural slate walling and decorative aggregates from Welsh Slate are bringing a soothing calm to the new headquarters of an international crime agency.

The manufacturer’s Cwt-y-Bugail blue/grey pillared and rustic walling and Cwt-y-Bugail blue/grey pillared and rustic blocks in various sizes, have been used for and around a 232m2 feature waterfall at the new €105 million offices of Eurojust, which combats serious cross-border crime and organised crime within the EU.

The walling and decorative aggregates are part of Welsh Slate’s architectural portfolio of products that also includes flooring and paving.

The new building enables the agency’s Netherlands personnel to relocate from two locations to just the one, in The Hague’s World Forum/International Zone area.

Developed by the Central Government’s Real Estate Agency, the Ministry of Justice and Security, and the municipality, the stringent security measures and complexity of the location required a carefully integrated design solution.

Mecanoo architects have designed a headquarters building that is an elegant composition of two volumes – a high-rise tower and a low-rise plinth on the park side – in which the rhythm of pure white composite façade elements gives the building a timeless, classic beauty. Windows are subtly tilted horizontally or vertically, reflecting both the sky and the surrounding landscape.

Mecanoo designed the landscape as one of undulating dunes with grassy vegetation and wild flowers, in collaboration with landscape architects DS Landschaparchitecten. By incorporating the security requirements within the landscape design, the building has retained an open character.

Inside, visitors are welcomed into a spacious, double-height lobby from which there is a gradual transition from open spaces to more private areas. A wide staircase, overlooking the dune landscape, descends to the conference centre. Higher levels feature contemporary office environments to encourage cooperation.

Eliano Felicio, marketing communications manager for Mecanoo architects, said: “We’re positive about the stone as it delivers the intended atmosphere and most of all responds to the security requirements that such a complex building demands.”

Frans Rombouts, manager for main contractor Heijmans who partnered with de Enk Groen & Golf on the landscaping element, said: “The contract was awarded on the basis of economically most advantageous tender, with the construction quality being a major contributing factor.”

The Welsh Slate walling and decorative aggregates were specified by Heijmans, supplied through Lei Import in The Netherlands, and installed by Roys Maatwerk.

Welsh Slate wins Westminster’s vote

September 2019

Welsh Slate wins Westminster’s vote

Two types of Welsh Slate feature on the new roof of London’s Irish Embassy.

The £2.5 million re-roof of the Grade II listed Irish Embassy in London, with more than 10,000 Penrhyn Heather Blue slates from Welsh Slate, has required its own exceptional levels of diplomacy.

DarntonB3 Architecture had multiple challenges to factor in when it came to specifying the replacement slates, including the City of Westminster’s planning department, which was keen to see as many of the existing slates re-used as possible and required convincing to embrace the “new” metric sizes.

Then there were landlords Grosvenor Estates, leaseholders the Department of Foreign Affairs and Trade, and Historic England, not to mention the site being opposite Buckingham Palace, on a “Red route” with diplomatic bays nearby, and between two of the most important Conservation Areas of Belgravia.

Work began on the landlocked Grosvenor Place site in March 2018, a year after DarntonB3, who are specialist conservation architects, were appointed to oversee the project, and has just completed (January 2019).

Two types of Welsh slates have been used on the former terraced town mansion with decorative metal roof crest that was designed by architect Thomas Cundy, who was surveyor to the Grosvenor Estate at the time, and built in 1868 in a French Renaissance style.

Roofing contractor Mundy Roofing was involved at an early stage in the project and were ultimately appointed as principal contractor. Specialising in leadwork and natural slate roofing, they were pivotal to the project’s success.

A total of 600m2 of County-grade 500mm x 300mm slates have been used on the numerous standard 30° to 35° pitched roofs while Capital-grade bespoke arrow-head slates of the same colour but sized at 400mm x 250mm were used around dormer windows on the 80° mansard roof elements that are reminiscent of Paris and feature lead secret gutter detailing around the perimeter. There is also some vertical slating to the rear elevation.

The old 5mm to 7mm thick slates had been on the roof since it was first built 150 years ago. The rectangular ones had been slightly longer and narrower, at 510mm x 255mm, while the arrow-head slates had been smaller all round, at 350mm x 200mm.

But a roof survey showed they were not laid to the correct bond or headlaps and fixing points were far from ideal and non-existent in places (the headlaps between 0 and 50mm), leading to the hardened sarking underneath becoming sodden in places. In fact, most of the roof had been repaired over the years with different types of slates using temporary lead tags or painted with a bitumen solution in an attempt to prolong its life.

DarntonB3 argued that if the roof was re-installed as existing, its appearance would alter as they would have no option but to lay the slates at the correct headlap which would create additional courses. In addition, using the slightly larger arrow-head slates for the mansard roof would enable them to form a more robust detail at the abutments to the dormers and party wall.

Home to the Irish Embassy for the past 70 years, the building comprises office and entertainment space. The traditional timber truss roof featured timber sarking boards with penny gaps, a form of construction usually found in Scotland. The slates were then fixed with copper nails directly to the boarding without any timber battens.

Once city planners had agreed to 100% replacement of the Welsh slates, at the new metric sizes (a process that took a year), the addition of timber counter battens, to improve ventilation of the roof and prolong the life of the new slates, was also proposed by the Architects.

Mundy Roofing produced sample comparison mock-ups to demonstrate to the conservation officer this change would not be detrimental to the building’s character. As it is, the interface details where slates have been lifted has not altered the character of the building and the introduction of battens would not be known by the general observer.

DarntonB3 senior associate Matthew Jones, who was project manager and lead architect throughout, said: “Westminster City Council are regarded as one of the leading conservation-led councils in the UK, with some of the highest standards and criteria to meet, and dialogue with the conservation officer was detailed and robust. The need for wholesale replacement of the existing slate due to them being at the end of their life was a delicate decision and sufficient evidence of this necessity was proven. The replacement of the slates with metric sizes was also an extensively discussed item but the principal contractor and Welsh Slate worked with us to develop the narrative.”

Keith Hamilton, an architect accredited in building conservation, acting for DarntonB3 alongside Matthew was reasonably sure Welsh slates had been used previously but was keen to ensure the correct thickness and grading were eventually used throughout the renewal process.

He said “We have specified Welsh Slate on numerous other projects and their reputation for the highest quality precedes them. We were able to argue the merits of increased ventilation behind the slates using cross battening in lieu of direct nailing to the existing sarking board, which in the majority of areas had survived over 150 years’ performance.

“The risk of lack of ventilation on the lower roof pitches behind the slates was particularly relevant at the eaves and head. We had previously considered introducing slate vents and felt underlay to augment any need for ventilation but the existence of the ‘penny gaps’ in the sarking boards encouraged us, to believe that this was not required.

“This was another point of continued discussion with the conservation officer who was against an underlay in this instance. The timber sarking was found to be in remarkable condition considering the lack of existing underlay and the direct fix of the slates, highlighting the quality of the original slates. Hence, there is no secondary layer apart from the slating itself and we trust the quality of the new Welsh slate will replicate the existing quality and last another 100 years.”

Due to tight access on the roof, they were also able to widen the lead gutters and set back the lower courses of slates to avoid getting them broken. All the new Penrhyn slates were holed and traditionally fixed with 38mm copper nails as opposed to clipped or other methods. The standard-size slates were able to cope with the wide variation of roof pitches and new rooflights encountered by varying the lap and gauge slightly.

In virtually every case, the slate junctions are with lead or copper flashings and as it was appreciated there is some risk of staining, all lead was treated with patination oil. Using new treated timber battens for fixing the new slates proved a great success as direct fixing into the old hardened sarking boarding would have been a major problem and time consuming.

Matthew said the support they had received from Welsh Slate had been “fantastic” and included a site visit to match the type of slate, a letter explaining the need to change from imperial to metric sizing, technical drawings of the arrow-head slates, technical information on the end life of slates and their unsuitability for re-use, on-time deliveries with little if no wastage, and recommending experienced slating contractors.

Mundy Roofing were on site for a total of 10 months. Work included the rebuilding of three chimney stacks, involving 30 tonnes of stone and brickwork, and restoration of traditionally-forged wrought ironwork to the pavilion roof crest, all underneath a temporary roof.

Russell Mundy said: “This project was extremely challenging due to it being a working embassy but Welsh Slate were excellent with their support in achieving planning consent and the product has received widespread praise from the client.”

Matthew said: “Due to the extremely difficult access to this roof, we were conscious to use a slate that will require little maintenance (if any) and satisfy appearance for an extended period of time. Welsh Slate were able to provide technical studies comparing different types of slate and their longevity. This enabled the landlord, Grosvenor Estates, that the new roof should outlast the previous roof and match it entirely with other buildings nearby. Welsh Slate’s evidence on the existing slates being at the end of their useful life, and the lifecycle information of the new slates, helped give the conservation officer comfort that the right approach was being taken for the building.”

Keith added: “Essentially, Welsh Slate ensured we got the right slate, quality, consistency and sizes for the varying roof pitches and conditions. There have been no problems with mixing batches or colour variations which can occur. They also met the stringent programme requirements, reducing risks of delay from the main contractor. To our knowledge, there have been no rejects on quality of slates.

“The final result is the new slating looks exactly like it was envisaged in 1868, except with the knowledge it is better-fixed and easier to reach for maintenance, with a discreet fall arrest system fitted. The client is extremely happy with the quality of the final works.”

Andrea Fox, senior architect with the property management unit of the Department of Foreign Affairs and Trade, said: “The team have provided us with an exceptional and beautiful project that we know will stand the test of time and one we are extremely proud to have commissioned.”

“I want to thank the Welsh Slate team for the support they provided during our project and especially in relation to protracted issues relating to the listed building consent approval.”

List all press releases