Ashford and Cranbrook Roofing is demonstrating its command of craft skills on the repair of a traditional Kent peg tile roof. Professional Builder’s Lee Jones talks to the company’s Managing Director, Wayne Wills about this ancient trade.
“If it’s old and rusty we’ll work on it,” declares Wayne Wills, and it is that dedication to the conservation of heritage roofs for posterity which has seen his company, Ashford and Cranbrook Roofing brought in to work on the restoration of the Society for the Protection of Ancient Buildings (SPAB) Old House Project.
The original ecclesiastical role of the 15th century St Andrews Chapel in Kent is just one of its many lives, from private residence to local Post Office. Uninhabited since the 1960s, this medieval survivor has been acquired by the charity to put its principles of repair into practice and operate as an invaluable educational resource along the way.
Four generations of the Wills family have trod the battens in the county called the ‘Garden of England’, and it is Kent peg tiles that have become their craft, as Wayne explains. “It’s very hard to source peg tiles in traditional sizes, because many of the clay tile manufacturers are producing the slightly wider and longer versions, which are no good on heritage jobs like these. That’s why we’re now producing our own Kent peg tiles with our stamp on them. It is a product that has been used since at least the 14th century so it’s certainly stood the test of time.”
It is King Edward IV who we can thank for the dimensions of modern tiles, when his statue of 1447 decreed that they should be 10 ½ by 6 ¾in. and 5/8in. in width. Locally made Kent peg tiles did not, however, adhere to the standard until the late nineteenth century, which is why examples such as the SPAB house are 9 by 6in.. “Because Kent peg tiles are smaller you need to know exactly how they should be applied. If you overstretch the gauge, for instance, there won’t be a headlap and it will start to leak. Water evaporation and air flowing around the tiles is also crucial to the longevity of a roof.”
St Andrews Chapel is, in fact, an object lesson on past transgressions and the use of inappropriate materials. During its Post Office era, a nineteenth century extension to the original structure made use of felt as an underlay. As a result, moisture has been trapped, rotting the timbers and necessitating a complete re-roof of that section.
“It’s about being respectful of a building that’s been around for a lot longer than we have,” enthuses Wayne. “The SPAB brief is, of course, to repair wherever possible rather than replace which is why, on the main part of this roof, there will be no membrane – just Kent peg tiles and battens. There is the option of wood fibre boards, providing insulation from beneath, but at the same time ensuring that vital airflow under and through the tiles is maintained.
“Those tiles are inspected individually and repaired, with each section tested for its structural integrity. There is also evidence of roosting bats on the site, which has required a ridge construction through which they can access, whilst at the same time maintaining a water bridge. Complex roofs are our stock in trade but they do require thought at every stage. We had to design the scaffold so that we’re not interfering with the roof in any way or breaking tiles, for instance, with a pole running the length of the ridge so that we can run a ladder from the scaffold onto that pole.”
On the SPAB project, everything that can be reused is, whilst a traditional lime kiln, built on the site, is producing the putty for pointing. The charity even experimented with using the clay from the grounds of the chapel to produce tiles in a local kiln, but the material proved to be too impure for their purposes. Since them Lincolnshire-based William Blyth have supplied these most traditional of tiles from a clay sourced from the River Humber, produced in a coal-fired, down draught kiln. Replacements for the softwood timber dowels that give Kent peg tiles their name will, however, be sourced on site, with up to 3,000 required for the repair.
Whilst many heritage projects would use aluminium alloy peg drops, this project is determined to preserve that historical accuracy. Indeed, this is a building material which is in perfect accord with its environment. Its distinctive rich orange-red variations in hue are derived from the clay used, whilst the firing process produces subtle distortions and cambers in the finished tiles, aiding ventilation and promoting a healthier roof.
“Working on heritage buildings is a craft,” concludes Wayne, “and one where you’re learning every day. Old buildings have a habit of throwing up surprises, and that requires a particular skill and attention to detail. On a job like the Society of Protection of Ancient Buildings project, where the ethos is very much to retain as much as possible and allow the building to tell its own story, that is a mindset that is even more in evidence.”
Ashford and Cranbrook Roofing cranbrookroofing.co.uk/
Society for the Protection of Ancient Buildings spab.org.uk/
William Blyth williamblyth.co.uk/