What is the best practice regarding the surface of footings?

The preferred practice for the surface of footings is to ensure they are flat. This flat surface allows for uniform distribution of the load from the structure above and ensures proper bearing capacity. A flat footing provides stability and helps to prevent differential settlement, which can lead to structural issues over time.

Having a flat surface also facilitates the placement of concrete and ensures that the footing adheres well to the ground. It simplifies the process of leveling and aligning your structure, which is critical in construction.

While other surface treatments like being rough or sloped may have their places in specific contexts, they do not serve the foundational purpose as effectively as a flat surface does in providing the necessary support and stability for residential construction. A rough surface might be useful in enhancing the bond with the concrete but does not contribute to the overall intended function of the footing itself, and a sloped surface could lead to uneven weight distribution. Therefore, maintaining flat surfaces is a best practice when it comes to footings in construction.