Durham Cathedral is the missing link between heavy Romanesque wall architecture and the slender Gothic skeleton: the birthplace of the rib, which gathers the load of roofing a stone vault from continuous thick walls onto a few linear lines.

The barrel and groin vaults that until then roofed large spaces spread all their weight along the thick wall beneath; walls therefore had to be massive and windows small. At Durham the builders try something different: stone ribs are first raised along the diagonals of the vault, and the lighter infill surfaces between those ribs are then closed. The rib acts like a skeleton — the vault's load now flows not through a continuous surface but along these linear lines, down to definite points at the corners and from there into the piers. Because the load concentrates, the wall between the ribs can cease to be load-bearing and begin to thin and open up.

Durham also shows early trials of the pointed arch; unlike the semicircle, the pointed arch can bring spans of different widths to the same height, freeing the geometry of the rib vault. When these two inventions — rib and pointed arch — are joined a few decades later at Saint-Denis with the flying buttress and stained glass, the Gothic will be born. Durham still looks heavy and Romanesque; but its structural logic belongs to the future: it is the first large application of the idea of freeing the wall from bearing and handing the load to a skeleton.