Typically, Kiln Dried Oak is recommended for indoor use due to its lower moisture content. Like all natural wood, oak may expand or contract with fluctuations in humidity and temperature. Proper installation, with expansion gaps where necessary, will help accommodate this natural movement and prevent warping or cracking over time.
For exterior projects, green or air-dried oak is often more suitable. However, if properly treated and maintained, it can be used outdoors in sheltered conditions where appropriate consideration is given for movement and seasonal swelling.