Historic Churches 2021

10 BCD SPECIAL REPORT ON HISTORIC CHURCHES 28 TH ANNUAL EDITION struck between the face of the quoin stones. Indeed, external finishes may well have started out as an integral base coat of the bedding mortar to the walling as recent research by Tim Meek and Paul Adderley is finding out¹. When, a few years ago, there was a partial collapse of the south wall of the tower, it exposed the west end of the south aisle, and here evidence of a lime render was discovered. Since the date of the tower is later than the south aisle, this render must be medieval (a sample of it has been retained for further analysis). Two further points to make: does it not tell us something that the south clerestory is rendered? And the north aisle and lady chapel confuse the issue as they are both Victorian, and their rubble facings (on a brick core) are meant to be exposed. Although not ideal from the point of view of keeping a solid wall dry, it is clear that a Victorian rubble wall is built in a considerably different manner to that of a medieval one. In particular, the bedding mortar is more robust, with no voids, there is often a nine- inch brick inner skin, and the external face of field stone, flint, or cobbles are packed together much more tightly. Something that medieval rubble walls have in common, when you get your eye in, is that the bedding mortars are in a very soft lime mortar, or perhaps even more likely a lime consolidated earth mortar. The masonry units are also much further apart, so there is a greater area of mortar exposed. Furthermore, there will be many cavities in the mortar, and I suspect these were always present from the date of construction; after all it would be nye on impossible to completely cover every face of every piece of irregular masonry unit, and neither did it matter because it was going to be covered up anyway. A sign that the cavities are old is the number of cobwebs that cover the surface, as these holes make excellent homes for spiders. However, as a result, these holes create perfect pathways for water to get deep into the core of the wall and saturate the masonry; this in turn means it takes longer for the wall to dry out. UPWELL ST PETER CHURCH, NORFOLK Sitting on the Norfolk and Cambridgeshire border, Upwell St Peter again suffers from the typical problems of a church having lost its external finishes. Quite apart from its astonishing medieval roof (which needs all the protection it can get), internal plasters are spoiled by damp and give the church a very forlorn and unwelcoming appearance. Externally, the fabric is in a parlous state with several buttresses on the point of collapse. Apart from the usual issues such as poor drainage, it is clear to me the rubble walling was rendered. Little evidence remains in situ, but a recent discovery of a 19th-century photograph clearly shows the church entirely rendered, as does another engraving by John Cotman. The fact that an internal plaster fall at the west end of the nave requires about six square metres of replastering can be no surprise when you look at the decayed ironstone on the external face. Mercifully, we have obtained consent to re-render this part of the elevation, but quite honestly the entire church needs it. ST MARY MAGDALENE CHURCH, MADINGLEY, CAMBRIDGESHIRE The picture of evidence here is a complex one, but on this one church alone there is a multitude of renders and techniques worth looking at. The chancel has been shortened and refaced by the Victorians, and earlier in the 19th century the north aisle was refaced in an extraordinary ‘crazy paving’ effect. You might like to discount the fact that the two-storied south elevation of the nave has been re-rendered and lined out (early C20, and I suspect a copy of what was there before); and again the Roman cement rendered remnant left on the east wall of the north aisle, and all of the pecking to the dressings which one very much doubts is medieval. However, older renders do clearly survive and would be worth further analysis. For a start the lower stages of the tower are clearly rendered and are showing signs of slow and inevitable decay of a soft lime mortar over many years. Left: An engraving by Cotman, c1817 of Upwell St Peter with uniformly rendered walls Right: A photograph of the church taken c1882 clearly shows the entire church rendered The poor state of this masonry at Upwell St Peter today, with many hollows and water traps, is typical. The idea of repointing around such decayed rubble seems unthinkable.