How To Grade A Foundation Floor

Foam insulation runs on the inside face of the airspace behind the brick.

How to grade a foundation floor.

The foundation wall may be an integral part of the load bearing design of the building carrying column and floor loads from above either as distributed loads on the wall or point loads on pilasters integral to the wall system. The word grade references the level of all the ground on your building lot before you start to dig a hole for the foundation. The foundation insulation is in the same plane and is applied to the slab edge below the termite shield down to the footing. The grade beam sits on a footing which provides support for the brick cladding.

Generally it is the siding that should be above the grade not the finished floor. The slope of the finished grade must be maintained at a minimum of 6 inches of fall within 10 feet. A good builder determines the highest point of ground near the home and sets the top of the foundation in relation to this high point. Concrete masonry is used to construct various foundation wall types including full basement walls crawlspace walls stem walls and piers.

Builders need to be sensitive to these established grades. If the building site has problematic soil such as expansive clays a raised floor foundation would perform much better than slab as slab would most likely crack on this type of soil. A raised floor is also used to raise the building above a floodplain. And drainage elements to the exterior of below grade foundation walls a slip plane should be introduced.

R404 1 6 height above finished grade. In some cases additional footings often a thickened slab are necessary under bearing walls or columns in the center of the slab. And also make sure the grade falls away from the foundation to be specific the 2015 international residential code irc requires the foundation to be 4 inches above the finished grade when covered by a masonry veneer or 6 inches elsewhere. Concrete masonry is well suited for below grade applications because of its strength durability economy and resistance to fire insects and noise.

The major structural components of a slab on grade foundation are the floor slab itself and either grade beams or foundation walls with footings at the perimeter of the slab see figures 4 2 and 4 3.