What is the maximum allowable slope for the bottom surface of footings?

The maximum allowable slope for the bottom surface of footings is established to ensure that the footing is placed on a stable base and is adequately supported. A slope of up to 10% for footings is permissible within the guidelines of many building codes, including those applicable in North Carolina. This limitation helps to prevent any potential issues related to stability and load distribution, which could arise from a steeper slope that might lead to uneven settlement or insufficient support under the foundation.

If the slope were to exceed 10%, it could compromise the effectiveness of the footing by creating an unstable condition, potentially leading to structural failure as the foundation itself may not rest uniformly on solid ground. This establishes the importance of maintaining a controlled slope in footing design and installation to ensure long-term safety and stability in residential construction.