Slope For Concrete Slab Drainage

But the reason for including any fall rather than making the surface level is to allow the concrete surface to drain.

Slope for concrete slab drainage.

Pour the sand into the trench sloping it toward the area you want the water to drain to don t drain it toward the house. If the slab elevation at the trench drain is within 3 4 inch of the plan elevation and the slab top elevation farthest from the drain is also within 3 4 inch of plan elevation the slab. So to calculate the difference in height between one end of a patio or walkway and another simply multiply the length by one quarter. Positive drainage requires a slope of 1 4 in ft 20 mm m however even at this slope some standing water often called birdbaths should be expected after a rain due to construction tolerances and normal surface deformations over time.

The proper slope for runoff drainage is a 1 4 inch of slope per foot of concrete slab. The standard slope for proper concrete drainage is a one quarter inch drop for every foot of length. If the slope is more gradual than this you may run into trouble getting water to run off properly. The recommended slope is 1 4 inch per foot but it can be anywhere from 1 8 inch to 3 8 inch per foot depending on other factors.

Slope the sand 1 inch for every 20 feet. A 2 slope will probably ensure better drainage we could also find no slope tolerance for use when a floor slope is specified. The patio needs to have a uniform surface to lay on. A concrete slab that is 10 feet long should have a slope away from the home of 2 1 2 inches.

Generally using 1 8 inch fall which is 1 1 4 inch per 10 feet works well on larger surfaces like driveways and patios but it requires good screed bullfloat and finishing operations to minimize water puddling birdbaths. Use a scratch template typically a piece of 2 by 4 or 2 by 6 lumber equal to the specified slab thickness with stakes attached to the top surface at each end or a string line across the top of the forms to ensure proper slab thickness. Aci 117 90 standard specifications for tolerances for concrete construction and materials gives a level alignment tolerance of 3 4 inch for top of slab elevation of slabs on grade. Calculate the ideal slope the standard formula for the slope of a concrete patio is a 1 4 inch drop for every foot of length.