Well, building houses (buildings, bridges, power stations, stadiums...) is usually fixed price, waterfall at that (the blueprint is prepared before construction starts, etc).
Of course, the clients can change the projects, that's what addendums to contracts are for. Here you define what changes and how the fixed price changes.
Among other things, it is great anti-slacker motivator. With time&material, the construction company could take whatever time they feel like. With FP, they are encouraged not to, because it goes on their tab.
Maintenance of buildings/whatever structures is on the ofter hand often done as a T&M (it is slightly more complicated, as there are a certain baseline services with fixed monthly fee and everything above that is T&M).