We all know the point on a slope of 6 inches in 10 feet minimum going away from the house - to drain water away from the foundation.
But in FL, it is basically all sand as “dirt” and sand has water run through it very quickly. And I have noticed that most houses have zero slope away from the foundation or not very much. Also, I don’t think there are many basements or deep foundations. I think most are slab on grade type foundations.
So for FL, I don’t think this spec applies about having to have a slope away from the house in many cases.
So my question is, what is the spec for FL? or is there an approved variance for this point?
Reference Florida Building Code Chapter 18 Soils and Foundations
2010 FBC
1804.3 Site grading.
The ground immediately adjacent to the foundation shall be sloped away from the building at a slope of not less than one unit vertical in 20 units horizontal (5-percent slope) for a minimum distance of 10 feet (3048 mm) measured
perpendicular to the face of the wall. If physical obstructions or lot lines prohibit 10 feet (3048 mm) of horizontal distance, a 5-percent slope shall be provided to an approved alternative method of diverting water away from the foundation. Swales used for this purpose shall be sloped a minimum of 2 percent where located within 10 feet (3048 mm) of the building foundation. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.
Exception: Where climatic or soil conditions warrant, the slope of the ground away from the building foundation shall be permitted to be reduced to not less than one unit vertical in 48 units horizontal (2-percent slope).