This thesis looked at the challenges and solutions for expanding a detached house upwards. The purpose was to present the specific features of the upward extension that may influence the choice of the extension method.

The subject of this thesis was limited to a timber framed detached house with foundations on bedrock, as this type of house is very common in Finland. In addition, a house of this type could be used as an example to illustrate the challenges and solutions.

The theoretical part of this thesis dealt with legislation and guidelines concerning construction and construction planning. In addition, the structures and the loads of the timber frame house were examined. The thesis focused on the most significant structures of upstairs extension.

There were three types of challenges facing upward expansion: structural challenges, implementation challenges, and challenges on functionality of the structure. As a result of the thesis, a structural or functional solution to the perceived challenge emerged. The challenges and their solutions were illustrated with calculations and figures.