CLARKE ROOFING RISE TO THE WELSH SLATE CHALLENGE AT ST LUKE'S

25 September 2023

Clarke Roofing’s work with Welsh Slate at St Luke’s Church wins them an award shortlisting.

As if reroofing the conical apse roof of a Grade II listed church was not challenging enough, the contractors for St Luke’s in Southsea were also tasked with removing a step in it.

However, Clarke Roofing Southern Ltd did such a good job that their work with Welsh Slate has now been shortlisted in the “Best use of slate for a commercial project” category in the Pitched Roofing Awards 2023 which will be decided at a gala event in Manchester on November 24th.

As well as the conical roof of the apse, which runs into the upper slate roof of the nave, Welsh Slate’s County-grade 500mm x 300mm Penrhyn Heather Blue slates, as supplied by distributors Yates & Company, were used on the main upper and lower roofs of the main church.

Welsh Slate was the original roof covering when the Neo-Norman flint and stone church was built by Thomas of Ryde between 1858-1861. It was completely re-slated almost 140 years later, in 1996, using existing sound slates and approximately 30% new Welsh Slate which is so sustainable it has a peerless guarantee of 100 years.

But almost 30 years later the formerly existing sound slates had deteriorated and the decision was made to re-slate the nave, including 10 dormer windows on the upper roof, the apse, north and south aisles, boiler room and south porch.

Now here’s the technical bit. The curved roof was set out as follows:

Template chalk lines were struck from the eave (at the width of the slate plus 5mm gap) to the apex.

Slates were taper cut to each side equally to fit the template lines.

Slates were cut from back with traditional cutting tools to produce a chamfered dressed edge.

Slate was cut no less than 245mm wide to provide suitable side-lap.

Where slates with the minimum width were used, Code 3 lead soakers were used with the following course of slates returning to full width.

Where slates could not be fitted due to them being below the minimum width to fit the curve, the slates were closely cut to fit the curve and made weathertight with Code 3 lead soakers.

The apex was completed with a Code 6 lead capping.

Clarke Roofing’s director/contracts manager Karl Strudwick said: “The most complex part of this project was the curved shape of the apse roof, forming part of the north and south elevations’ upper roof. The existing roof had a step where it meets the nave, which was formed as a verge to weather the apse junction with soakers and lead flashing.

“Our carpenters and slaters were tasked in removing the step so that the curved slate roof of the apse continued across the nave elevations without it. Once the alterations had been made to the apse roof, the entire church was then completely re-roofed using all new Welsh Slate from Penrhyn Quarry.

“The exceptional Welsh Slate is one of the best roofing slates available and is highly resistant to acid and other chemicals, making it extremely durable.”

As well as the apse challenge, Clarke Roofing also had to maintain safe public access as the church continued to be used during the works. The bottom of the scaffolding also had to be covered with 3m high continuous hoarding to prevent access, including fitting lockable covers to all ladders which were locked at the end of each day.

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