What is the maximum slope permitted for exterior landings?

The maximum slope permitted for exterior landings is indeed 0.25 unit vertical in 12 units horizontal. This means that for every 12 horizontal units, the landing can rise a maximum of 0.25 vertical units, which translates to a slope of approximately 2.08%.

This requirement is established to ensure safety and accessibility. A slope that is too steep can pose a hazard, particularly for individuals with mobility impairments. By adhering to a maximum of 0.25 unit vertical over 12 units horizontal, the design maintains a safe and gentle slope that helps facilitate safe navigation for people using these exterior landings. This is crucial in the context of building codes and standards, which aim to create accessible environments.

In contrast, slopes that are steeper than this specified measurement increase the risk of slips, falls, and difficulty in ascending or descending, which is why the standards prioritize a shallower slope such as the one mentioned in the correct response.