Why Do Roofs Have Different Shapes?

Look at pictures of houses from around the world: a house in snowy Switzerland has a steep, pointy roof. A house on a hot island in the Caribbean might have a flat roof with a wide, shady overhang. A house in the rainy Pacific Northwest often has a long sloped roof too. Roofs are not just decoration -- builders shape them on purpose to solve a real problem where they live!

- Why some roofs are steep and pointy while others are flat - How weather like snow, rain, and sun shapes building design - New words: architect, slope, and overhang - How to look at a building and guess why it was built that way

In places that get lots of snow, like the mountains of Switzerland or parts of Canada, houses often have steep, pointy roofs. A steep roof has a big slope, which means snow slides right off instead of piling up. If a roof were flat in a snowy place, all that heavy snow would sit on top of the house, and heavy snow can be so heavy it makes a roof crack or even cave in!

In hot, dry places like parts of the Southwest United States or North Africa, many houses have flat roofs. There's no heavy snow to slide off, so a flat roof works fine. Flat roofs are also useful -- people can use the rooftop as extra space to sit outside in the evening when it's cooler, or to dry food in the sun.

In places that get a lot of rain, like the Pacific Northwest of the United States or parts of Japan, roofs often have a long overhang -- an edge that sticks out past the walls of the house. The overhang works like an umbrella for the building: it pushes rainwater away from the walls and windows, so the house stays drier and the wood doesn't rot as fast.