All things ferrous
One of the great myths surrounding the story of medieval Gothic architecture is the claim that the clever masons of the Middle Ages found a new way of constructing impressively tall churches and cathedrals with large expanses of tracery and stained glass by using pointed arches and vaults that become stronger the more they are compressed, along with massive buttresses to carry the weight of the stonework to the ground. Anyone who has been privileged to visit the hidden parts of a medieval cathedral will confirm that this is not the whole story: large quantities of ironwork were also employed to hold the building together.
The masons’ skill was to hide the ferramenta, as it is known, underneath floorboards and in the space above the vaults to give the appearance that the stonework is self-supporting. In particular, the adjacent blocks of stone that make up the walls of the cathedral have holes and channels carved into the surface to accommodate massive iron staples that are secured with molten lead – literally stitching the blocks of stone together. Iron tie-rods located above the aisle, nave, and sanctuary vaults help to keep the walls from leaning outwards and spreading. The stonework of the nave and sanctuary arcade columns is also full of iron pins to prevent the component blocks from sliding apart and collapsing.
On a medieval building site, iron-working was thus as integral a part of the building process as stoneworking. The failure to recognise this has led to some near disasters: the belief that the use of iron armatures was a feature of 19th-century restoration led to the tie- rods at Beauvais cathedral being removed, leading to major structural issues.
The Princess of Khok Phanom Di