Winner of ‘Best Heritage Roof’ in the 2018 Pitched Roofing Awards
DREADNOUGHT ROOF TILES, one of the UK’s oldest and well-established manufacturers of traditional clay roof tiles, has won the heritage category in the first ever ‘Pitched Roofing Awards’.
The national awards showcase excellence in the roofing sector, highlighting successful partnerships between manufacturers and contractors and recognising commitment to quality.
The winning project in the ‘Best Roof Tile Application for a Heritage Roof’ category was St Mary’s Church, Bushbury, which used Dreadnought Tiles working with specialist contractor Four Oaks.
The restoration of St Mary’s Bushbury
The Church of St Mary, Bushbury in Wolverhampton, is a Grade II* listed building which dates back as far as the 14th Century.
The building reveals two different characters: the chancel and tower which have an irregular medieval fabric, and the nave, the north and south aisles and the organ chamber, which were rebuilt in the 1850’s by the architect Edward Banks and are of a more typically precise Victorian fabric.
The restoration involved the re-roofing of the 56-degree roofs on the nave, the south aisle, the chancel and the organ chamber. All of these had previously been covered with blue clay plain tiles, typical of the area, which were fitted in the 1850s and were now in need of replacement. The tiles had been bedded in lime mortar, with no nailing whatsoever, and most of this bedding had fallen away, along with many of the tiles, causing considerable water ingress.
Access to the Church Roof
Access to the Church was extremely difficult for the main contractor Four Oaks, as all of the tiles and equipment had to be brought in from the road along two sides of a narrow path on a dumpster truck. The site is also exceedingly tight with graves lying up to the edge on both sides of the path, as well as right up to the outside walls of the church.
David Small from Fair Oaks explained: “This made access to the roof and positioning of the scaffolding particularly difficult and it was also very awkward finding enough space to position the hoist to get the tiles up onto the roof.”
It was only once the scaffolding was up, that a really thorough investigation of the roof could be carried out and this revealed a number of issues that had not previously been accounted for, particularly relating to the old Chancel building, where the contractors found damage to major medieval supporting roof beams from death watch beetle, which would need to be repaired and reinstalled.
The Chancel building
The irregularity of the Chancel building, due to its age, also presented significant challenges as the removal of the old tiles revealed old lath and plaster beneath, to which it was not possible to fix the battens.
By fixing 2 by 2 counter battens and then 2 by 1 tile battens, a void was created above the old lath and plaster, which effectively raised the height of the tiles against the coping stones on the gable ends. Architect Bryan Martin said: “Four Oaks went to great lengths to set and pack our new counter battens, so that the very characterful undulations were preserved.”
However, the new height of the tiles made it difficult to fix flashing beneath the tiles and up and beneath the coping stones, so the tiling was terminated short of the gable end, leaving a small gap to create an extremely neat lead-lined secret gutter at the parapet abutment.
The decaying parapet coping stones were also replaced and re-bedded. Instead of nailing the new tiles, which would have damaged the old plaster inside the church, the tiles were fixed to the battens using screws.
The Victorian Roof
The Victorian roofs presented rather different challenges. It was evident that, at some point the south eaves of the south aisle roof had been altered to oversail a previous inadequate gutter carved into the head of the wall. The altered section had been laid nearly flat, and the tiles were simply bedded on roughly laid bricks and large amounts of hard cementitious mortar. This had caused water to discharge straight into the wall rather than into the gutter.
Four Oaks carefully removed all of the roughly laid bricks and cementitious mortar and repaired the wall stonework that had been damaged by the hard mortar and water leaking through the badly laid tiles. They then fitted new counter battens and introduced a gentle sprocket at the eaves, giving a new and somewhat elegant profile, whilst ensuring that in future water would discharge properly into the restored cast iron gutter.
Matching Staffordshire Blue tiles
Architect Bryan Martin decided to re-roof with tiles that matched the originals as closely as possible, laying them in alternating four-course bands of plain and fishtail tiles just as before.
Dreadnought were able to provide tiles that were an extremely close match. Furthermore, it seems likely that the originals may have come from a very similar source, and perhaps could even have been originally manufactured by Dreadnoughts, as the shape and colour of Dreadnought’s tiles have not changed over the years. The authentic Staffordshire blue colour has always been achieved through the control of the kiln atmosphere, which turns the iron content in the clay to blue.
A total of 14,250 fishtail and 32,000 plain Staffordshire Blue tiles by Dreadnought were used, as well as two matching bat tiles and approximately 140 300mm angle ridges. In addition, all of the old tiles were carefully sorted and the best ones were reused on the roof of the organ chamber. As none of these old tiles had nailing holes, each of the tiles had slots carefully cut to allow them to be fixed to the battens.
An impressive achievement
Architect Bryan Martin said, “Four Oaks carried out the meticulous repair of a batch of the ornate crested 1850s ridge tiles for the organ chamber roof, combining the best of the base tiles with the best of the cresting. Needless to say, we are all extremely pleased with this roof too.
“It is notable on the whole project that the tiles are extremely evenly laid, very carefully set out, and the coursing is nicely managed at the abutments to avoid narrow cuts. However, this was by no means a straightforward job.”
The Reverend Doctor Ian Poole commented: “Everybody associated with the restoration is delighted with the result, it looks fantastic and we very much hope it will give a further 200 years of service to the Bushbury Community.”