New high-rise timber buildings are planned to be built in the near future all around the world. The fire protection concepts are not always considering natural fire scenarios. As timber is a combustible material, it can contribute to the fire within and outside of the fire compartment. For buildings with cross-laminated timber (CLT) elements the possible fall-off of lamellas should be considered because of the risk for second flashover, which can lead to a continuous fire. However, in case fire service interference or sprinkler activation is absent or inefficient, it may be necessary to design a building so that it leads to a decaying fire. Additionally, it is important to limit fire spread to neighbouring compartments. This paper discusses a compartment test of a two-story building made of CLT performed in Estonia to study delamination behaviour and consequences in compartments with realistic ventilation conditions. State-of-the art solutions to limit fire spread from the first floor into the second floor were applied. This involved robust design of connections, penetrations through the compartment boundary and the façade. The paper provides a description and analysis of the test.