You don’t have to be an expert in construction to know that wood burns. You might also recall that parts of London were destroyed in the Great Fire because they were made largely of wood, after which they were rebuilt in brick and stone. So it will seem a reasonable reaction to the Grenfell disaster that the government banned timber (along with other combustible materials) from the exterior of residential buildings more than 18 metres high.  …But there’s a cost to this caution, which is that it will impede one of the most promising recent innovations in building. …High-performing timber construction will continue to expand, in other words, in many parts of the world, but will be held back in England.  …Part of the problem is that the current ban doesn’t adequately distinguish between the cladding, or outer skin of a building, and its structure.