# "Slopes  Of  Land"  Away  from  Commercial  Bldgs.



## north star (Jan 30, 2018)

*@ ~ @*

Greetings all !

I seem to remember a few Code cycles ago, in a Single Family Residential
application, that the IRC used to require that:  "At 12 inches away from the
exterior wall, the grade [ land ] shall be sloped a minimum of 6 inches lower
than the top of the foundation".

*QUESTION # 1:*  Am I correct in this "foggy rememberance" ?
*QUESTION # 2: *Is there a requirement in the IBC for the grade at the
exterior walls to be a certain [ minimum ] distance lower than the top
of the foundation ?

Thanks for your input !* *

*@ ~ @*


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## classicT (Jan 30, 2018)

IRC Section 401.3 - The _grade_ shall fall a minimum of 6 inches within the first 10 feet


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## classicT (Jan 30, 2018)

Also, Section 317.1 may help.

Protection from decay shall be provided for :_ "5. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less that 6 inches from the ground or less than 2 inches measured vertically from concrete steps, porch slabs, patio slabs and similar horizontal surfaces exposed to the weather."_


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## mtlogcabin (Jan 30, 2018)

2012 IBC
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).

The procedure used to establish the final ground level adjacent to the foundation shall account for additional settlement of the backfill.


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## ICE (Jan 31, 2018)

I do believe that there is a code that requires an eight inch separation between a mudsill and dirt.


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## MtnArch (Jan 31, 2018)

R317.1 in the California Residential Code is where you're thinking ICE.


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## Paul Sweet (Jan 31, 2018)

I don't know of any requirement for wood to be a minimum distance from the ground, but IBC 2304.11 requires naturally durable wood or pressure treated wood in several locations near or below grade.


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## my250r11 (Jan 31, 2018)

GRADING & DRAINAGE
Grading F20 09 IRC
n Grade surface to storm drain or other approved collection point______ [401.3]
n Grade away from foundation min 6 in. fall within 1st 10 ft. EXC_______ [401.3]
• Use swale if physical barrier or lot line prohibits 6 in. fall in 10 ft.___[401.3X]
n Hardscape within 10 ft. min 2% slope from building_______________[401.3X]
Drainage 09 IRC
n Top of foundation min elevation above drainage inlet or street gutter
12 in. + 2% slope_ ________________________________________ [403.1.7.3]
n If water does not readily drain from site, crawl space on same level
as outside grade or install approved drainage system_______________ [408.6]
n Roof drain must discharge min 5 ft. from footing or to approved drain
system if soils expansive or collapsible___________________________ [801.3]

Sills 09 IRC
n Sills < 8 in. from exposed ground PT or naturally durable wood_______ [317.1]
n Sills & sleepers on slabs PT or separated by moisture barrier________ [317.1]
n Min 2×4 nominal size_________________________________________ [404.3

n Grading to provide req’d slopes & clearances; 6 in. siding to soil,
2 in. siding to hardscape F27_______________________________ [317.1#5]75


This from my 09 IRC code check


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## JBI (Feb 6, 2018)

The language in the IRC and IBC is slightly different but the result is the same... 6" drop in the first 10' or one of the other methods to protect the building from surface runoff.


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