A sloped roof design is preferable for a doghouse as it facilitates water runoff, preventing accumulation and potential leakage, thereby ensuring the doghouse stays dry and comfortable. Additionally, a sloped roof helps in reducing the buildup of debris and snow, which is particularly beneficial in areas with heavy rainfall or snowfall. In contrast, a flat roof can provide a secondary function as a lounging area for the dog, especially in mild climates. However, it requires more maintenance to prevent water pooling and potential leakage.