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Grading

K

Keystone

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Feb 23, 2010
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Location
Lehigh Valley, Pennsylvania
2009 IRC - R401.3 Drainage. Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm) within the first 10 feet (3048 mm).

Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152 mm) of fall within 10 feet (3048 mm), drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.

When a home or a free standing addition to a home rests on piers and the bottom plate of the home is 3" above grade (no floodplain) would section 401.3 apply?
 
The intention is to keep surface runoff from gaining access to the habital spaces. You would not want water to pond under the house.

If these objectives are met I would see no problem with water flowing under the house.
 
Keystone, I believe you meant to say the sill is 3' above grade; whether your AHJ enforces Property Maintenance Code;

302.2 Grading and drainage. All premises shall be graded and maintained to prevent the erosion of soil and to prevent the accumulation of stagnant water thereon, or within any structure located thereon.

The section that Mark K is refering to:

R408.6 Finished grade. The finished grade of under-floor surface may be located at the bottom of the footings; however, where there is evidence that the groundwater table can rise to within 6 inches of the finished floor at the building perimeter or where there is evidence that the surface water does not readily drain from the building site, the grade in the under-floor space shall be as high as the outside finished grade, unless an approved drainage system is provided.

Francis
 
I hope this thread isn't too old to add to.
I'm currently building a home in Wake County, NC.
My question is about where the foundation drainage is allowed to terminate. The builders in this neighborhood use perforated drain pipe. All of the homes seem to have 3 or 4 of these running under the crawlspace to a low point in the yard where the pipes terminate to daylight.
Is it acceptable for the pipes of one home to terminate into a neighbors yard?
There is a public easement behind all 3 homes that would seem to make more sense as the termination point as it is the lowest area.
Also, do the pipes have to extend a certain distance beyond the foundation walls?
Thanks in advance for any/all feedback.
 
EricTengo said:
Is it acceptable for the pipes of one home to terminate into a neighbors yard?
Click to expand...
Not typically. Stormwater and other runoff must typically be maintained on ones own property. This is typically in the municipal code or state laws.
 
What terms would I search for to find this info? I spent hours reading different publications and haven't found anything except ....
"Drain to storm drain or other acceptable area."
Who/what determines what is "acceptable".
 
I can't say what happens in North Carolina but it's probably similar to California.

Natural drainage courses are allowed to continue whereas concentrated flows are prohibited. Daylighting a foundation drain on an adjacent property is not allowed. As to the distance away from a structure, well the code doesn't have much to say about that.

"Drain to storm drain or other acceptable area."
Who/what determines what is "acceptable". The who is you. Whatever suits you on your property. The water will ultimately get to the storm drain...or not. It could percolate....dissipate....evaporate.

R401.3 Drainage. Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall not fewer than 6 inches within the first 10 feet.

Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches of fall within 10 feet, drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet of the building foundation shall be sloped not less than 2 percent away from the building.
 
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Not in CA, must drain via a noncorresive device to the public way or storm drain (which ever is allowed by AHJ) Too many past examples of slope failures due to uncontrolled runoff.
 
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