Until the late 19th century, sod roofs or turf roofs (a type of green roof covered with sod on top of several layers of birch bark) were the most common type of roofs on rural log houses in Norway and large parts of the rest of Scandinavia. The term ‘sod roof’ is somewhat misleading, as the active, water-tight element of the roof is birch bark. The birch bark underneath ensures that the roof will be waterproof. Sod or turf for roofing was cut from good pasture land, preferably with sandy soil. A naturally grown grass with a deep root system was desirable. A total thickness of about 15 cm is enough to make the sod survive a dry summer. Now that you know more about these interesting traditional Scandinavian house, click start and start putting the red log cottage featured in this puzzle back together piece by piece. Have fun!