Prismas stora ordbok. As easy as that.

http://www.swedesintexas.com/readingroom/rr0002.htm
Backstugesittare was a term used for people living in small houses or sheds etc on a landowner’s land or on the village common land. These houses, backstugorna (pl.), were exempted from taxation. Backstugesittare were without any assets and were a motley crowd of people consisting of craftsmen, farm workers as well as old people and the very poor.

In the south and southwest parts of Sweden they were called gatehusmän and in the southern parts of Norrland utanvidsfolk. On the westcoast they were also called strandsittare.
The backstuge houses were often collected in groups of houses outside the cultivated land area of a landowner’s land (with the permission of the landowner). Normally there were a small strip of land belonging to these houses where they could grow potatoes and keep some pigs and poultry. Sometimes they also had the possibility to use the farmer’s farmland. However, normally they earned their living as farmhands, craftsmen etc. They had no permanent employments and the backstugesittarna were often underemployed and underfed. The number of backstugesittare increased a lot between 1750 and 1850.
It was common that the backstuge houses only had three proper walls. The fourth wall was made of earth if the house was built in a slope.
In other words, the backstage houses were more or less hovels