Walter Verhoeven BV celebrates 140 years in business.
Dutch roofing company Walter Verhoeven BV has worked with Welsh Slate for all its 140 years, but it was only this year that contractor’s employees got to see the manufacturer in action.
Managing director Wim Verhoeven flew his brother Thom and 21 other colleagues over in February for a 140th anniversary two-day trip to the UK, one of which was spent visiting Welsh Slate’s main Penrhyn Quarry in North Wales.
Here they witnessed the full production process, from rock face, through sawing, splitting and dressing. Some even tried their hand at splitting the premium Penrhyn Heather Blue slate themselves.
The visit brought home the differences between the slate sector in the UK and The Netherlands where roofing slates are typically almost half the size of British slates – 300mm x 200mm (12” x 8”) or approximately 45/m2, and seldom longer than 350mm/14”, compared to 500mm by 250mm (20” x 10”) or approximately 20/m2.
The reason for this is twofold. Firstly, slate production in the north-east of Belgium and Northern Europe was predominately in small sizes, due to the material’s inferior quality. So, the architectural style developed to accommodate these small slates which could be incorporated into complex roof designs not feasible with the larger slates sold in the UK. Hence the proliferance of steep roofs and mansards on the North European mainland.
Secondly, small slates were produced in Wales as a by-product of the manufacture of the more familiar, larger slates, so were both readily available and sold at a comparatively low price, as there was no market for them in the UK.
The small size of slates used in The Netherlands also impacts their fixing method. This relies on hooks rather than double-nailing each slate, a process that is approximately 10% quicker, at five to 10 minutes/m2, than the UK process.
Walter Verhoeven is a family business and now run by Wim and Thom, the fourth generation. But Welsh Slates have been shipped to the low countries of Europe since the 13th Century.
The big growth in sales to these areas, due to the durability of the superior Welsh Slate product, corresponded with the massive growth of the Welsh Slate industry from the end of the 18th Century to its height in the late Victorian period of the 1880s.
Their team of up to 18 craftsmen has used hook fixings on small Welsh slates on more than a thousand buildings in The Netherlands.
Now specialists in slate, and zinc, lead and copper roofing, 90 to 95% of their work comprises the re-roofing of heritage buildings such as chateaux, churches, cathedrals, castles, monasteries and civic buildings (which the Dutch Government pays grants towards), with new-build houses, shopping centres and business premises making up the remaining five to 10%.
To work on heritage buildings in Holland, there is a preference for roofing contractors who are certified for disciplines like slate and metal roofing and Walter Verhoeven BV is proud to have had all these certificates since they were introduced.
While their employees do not have to complete a seven-year apprenticeship to become a Master Slater, such as in Germany, the company takes such pride in its own heritage expertise that it will turn down contracts where the brief is not for a quality job.
Currently, Walter Verhoeven is re-roofing a villa that was only built 11 years ago but where the Chinese slate roof has already failed due to poor materials and workmanship.
Poor-quality projects are increasingly the case, with many heritage buildings such as churches being forced to close due to lack of visitors and therefore income. These are then being converted into apartments or commercial/retail units by developers who not always want to invest in a re-roof or are happy to only pay for a cheap, and therefore sometimes inferior job.
Two heavily-detailed projects Walter Verhoeven is particularly proud of was the re-roofing, with 400m2 of Welsh Slate’s Penrhyn Heather Blue slates, of a castle with 16th Century origins in Berlicum which was being converted into a private home, and the re-roofing, with 700m2 of Cwt-Y-Bugail slates, of an enormous 100-year-old villa in Helmond.
Wim said: “We like to work with Welsh Slate as it is the best quality and easily lends itself to the complex roof structures we work on. The colours and structure of the Welsh slate are very nice and they have proven their quality over the years.”
This work ethic is already apparent in potentially the fifth generation – Thom’s 19-year-old son who already has metal roofing qualifications and is now into his second year working with slates, alongside a colleague who has worked for the company for 32 years.
It’s all a far cry from the early days when the business was set up by the brothers’ great-grandparents. Wim and Thom’s parents combined roofing with the installation of gas, water and plumbing in houses but that side of the business was divested almost 20 years ago when it could not compete against the growing number of sole traders. Then, slate comprised 40% of the business. Now it is almost 80%.
Looking to the future, Walter Verhoeven employs two apprentices who were looking to start college just before the country went into lockdown, on a training scheme that had been restored after it shut down during the 2008 recession. Now they hope to start this month (November), COVID permitting.