The path went across short sunny grass, to the edge of the bank. Down below it was the creek, rippling and glistening in the sunshine. The willow trees grew up beyond the creek.
Over the edge of the bank, the path turned and went slanting down, close against the grassy bank that rose up like a wall.
Laura went down it cautiously. The bank rose up beside her till she could not see the wagon. There was only the high sky above her, and down below her the water was talking to itself. Laura went a step farther, then one more step. The path stopped at a wider, flat place, where it turned and dropped down to the creek in stair-steps. Then Laura saw the door.
The door stood straight up in the grassy bank, where the path turned. It was like a house door, but whatever was behind it was under the ground. The door was shut.
On the Banks of Plum Creek, Chapter 1, The Door in the Ground
A sod house, also known as a “soddy,” is a type of dwelling that was commonly built by pioneers on the American frontier during the 19th century. The walls of a sod house were made of blocks cut from the thick sod of the prairie grasslands. The blocks were piled on top of one another and then packed tightly together to create the walls of the house. The roof was often made of wood or canvas, and the floor was typically made of packed dirt.
Sod houses were a cheap and relatively easy way to build a house on the frontier, where there were few trees and traditional building materials were not readily available. They provided insulation against the cold and kept the interior cool during the hot summer months. However, they were also prone to leaks and could be infested with pests such as mice and insects. They were also not very durable and had to be rebuilt frequently.
Laura never commented about any of these issues, other than leaks or when an animal’s foot went through the roof one day. It was also commented how hard it was to keep a dirt floor clean while they lived in the dugout, before Charles built them a permanent home.
Sod houses were mostly built in the Great Plains region of the US, where the prairie grasses were thick, and trees were scarce.