Church of the Nativity Roof

The Church of the Nativity in Bethlehem, Palestine, stands over the site venerated as the birthplace of Jesus. Its basilica is roofed with timber trusses covered in lead sheet, and the condition of that roof shaped the building's recent history: rainwater was seeping into the church through the deteriorating roof.

Danger listing

The church and the Bethlehem pilgrimage route were inscribed on the World Heritage List in 2012 and placed on the List of World Heritage in Danger at the same time because of the poor state of the building. The roof had not received major repairs since 1480, in the Mamluk period.

Restoration from 2013

Work began in 2013, initially with a private donation, after leaks through the deteriorating roof had become obvious. The Italian firm Piacenti carried out the work to UNESCO specifications following an international tender. Key roof measures reported by Arab News:

• the whole roof was re-covered with about 1,625 m² (17,500 sq ft) of new lead sheet;
• about 8% of the timber trusses were replaced with aged timber brought from Italy;
• steel connectors were added to the trusses to improve resistance to earthquakes.

The programme went on to restore facades, mosaics and doors. In July 2019, at its meeting in Baku, the World Heritage Committee removed the site from the danger list, citing the quality of the work on the roof, facades, mosaics and doors.

Why it matters for roofing

The project illustrates the role of a heritage roof as the first line of defence for everything beneath it. Lead sheet on timber is a long-lived system (see lead-roofing and medieval-lead-roofs), but only if the laps, fixings and supporting timbers are maintained; once leaks start, damage spreads to structure and interior finishes. The approach taken, keeping most original trusses, replacing only failed members with matching timber and adding discreet seismic connections, reflects current conservation practice.