Want to build an igloo? Here's how

IGLOO SPIRAL

The bricks of your igloo should spiral upwards in one continuous coil.

Digging a tunnel out of your igloo helps to keep out the cold, but Sijpke says it's easier to just cut your doorway out of the wall. Then you can take the block of ice you removed, cut it in half, and lean the two sides together to make an awning over your igloo doorway, to help keep your body heat inside.

Ice is stronger than snow, so freezing a layer of water on top of your igloo will keep it standing for longer.