History of Roofing Fire Regulations

Fire has shaped roofing more than almost any other force. A roof of dry thatch or wooden shingles catches flying sparks easily, and in dense towns one burning roof can ignite the next. For centuries, authorities have responded by restricting combustible roofs and encouraging tile, slate and metal.

Medieval and early modern Europe

• London, 1212: after a major fire, new thatched roofs were banned and existing ones had to be plastered over.
• 1613: the original Globe Theatre in London burned down when a stage cannon set its thatch alight, a famous illustration of the risk.
• London, 1666-1667: after the Great Fire, the Rebuilding of London Act banned exterior wood and favoured brick and stone.
• Hamburg, 1842: the city's great fire was followed by heavy rebuilding; Germany became an important export market for Welsh roofing slate afterwards.

Japan

In Edo-period Japan, dense timber cities were frequently destroyed by fire. The shogunate and domains encouraged clay tile roofs as a precaution, spreading tiles from temples and castles to ordinary houses. The lighter single-piece pantile developed in 1674 made this more practical.

North America

• Boston, 1631: the town's first fire-prevention ordinance (dated 1630/31) banned thatched roofs and wooden chimneys, according to the Boston Fire Historical Society. Building rules of 1678 called for slate or tile roofs and brick walls.
• Boston, 1872: a fire that spread across wooden mansard roofs destroyed 776 buildings. In its aftermath fire chief John Damrell campaigned for building codes, and Boston established height and area limits in 1892.
• 1905: the National Board of Fire Underwriters published the National Building Code, the first standardised US building code.
• 1916: the same body called for wood shingles to be eliminated as a fire hazard, which helped the rapid growth of asphalt shingles.

Modern fire ratings

Modern building codes generally regulate roofs through tested fire performance and rules for where combustible coverings may be used, rather than relying only on outright bans. Fire risk to traditional roofs persists: in the UK, 50-80 thatched roofs are destroyed by fire each year.

Pattern

Across these cases the sequence is similar: a catastrophic fire, a ban that is often poorly enforced at first, then gradual replacement of combustible roofs as non-combustible materials become cheaper.