Sheets of lead might be used to cover roofs of both timber (Constantine’s basilica of the Holy Sepulchre: Eusebios, VC 3.36.2) and masonry (Sts Sergios and Bakchos, Hagia Eirene, Hagia Sophia). They could also be used as cushioning at the springing of arches or between columns and their capitals (Paul the Silentiary, Description of Hagia Sophia 476-80). Lead was also used to grip and cushion glass panes in the shops at Sardis, and, in Constantinople, at St Polyeuktos, Christ Pantokrator, and Christ in the Chora (von Saldern 1980:92; Harrison 1986:204; Megaw 1963:349,365; Henderson and Mundell Mango 1995).
Bronze tiles were used to decorate the exterior of the roofs of prestige buildings, such as that of Constantine’s burial place (Eusebios, VC 4.58) and the roof of
St Peter’s, for which Pope Honorius I (625-38) stripped the tiles from the Temple of Roma (Lib. Pont 1.317 and 323) (an illustration, incidentally, of how the ancient temples were considered a ready source of spolia in the Byzantine period). The Masonry Obelisk set up, probably by Constantine I, in the Hippodrome at Constantinople was sheathed in bronze (Mango 1993: 17-20), as was a tetrapylon apparently erected under Theodosios I (Mango 1972: 44-5). Justinian’s masonry column in the Augustaion was covered with bronze plates and hooped with bronze garlands (Prok. Buildings 1.2.3-4).
The Byzantines followed Greek and Roman precedents in the use of iron for cramps and tie-bars (Lancaster 2005: 113-29). Iron cramps, either dovetail - or pi-shaped, were used to join together ashlar blocks, and molten lead was poured into the cramp-holes to prevent the iron from corroding (the lead, but not the iron cramps, is referred to by Prok. Buildings 1.1.53, writing of the piers of Hagia Sophia; see also ‘Walls of solid stone’ above). Iron might also be used instead of wood for tie-rods beneath arches in arcades (Wilcox 1981: 49 ff.; Ousterhout 1999: 210-16; Mainstone 1975: 70-1; Tanyeli and Tanyeli 2004: 23-38). It was also employed for ties between adjacent cornice blocks in centralized buildings, thereby creating, it has been argued, tensile chains containing the thrusts of vaulted roofing systems (Butler 1992). Columns might be bound with metal hoops to prevent them spalling or even splitting when under pressure. This was done with Constantine’s porphyry column in 416 (Chron. Pasch. 1: 573) and with the columns of verd-antique and porphyry in Hagia Sophia, which were given bronze collars at top and bottom, and often at intermediate positions (Mainstone 1988: 42 and pi. 42).