If tuff beds are thick enough or hot enough, they can consolidate into a fairly strong rock. The city of Rome's buildings, both ancient and modern, are commonly made of tuff blocks from the local bedrock. In other places, tuff may be fragile and must be carefully compacted before buildings can be constructed on it. Residential and suburban buildings that short-change this step remain prone to landslides and washouts, whether from heavy rainfall or from the inevitable quakes, like that which struck San Salvador in Central America on 13 January 2001. There many buildings on the local tierra blanca tuff collapsed.
See more closeup pictures of tuff, plus other related rocks, in the gallery of volcanic rocks.