Foundation above Grade 2009 IBC

[Mule]

Okay... 2009 IBC I thought there was a section of the code that specified that the foundation must be above grade by a minimum of 6". Am I going crazy or what? Is that still a requirement? Was it ever in the code?

 

[imhotep]

Okay... 2009 IBC I thought there was a section of the code that specified that the foundation must be above grade by a minimum of 6". Am I going crazy or what? Is that still a requirement? Was it ever in the code?

2009 IBC

2304.11.2.2 Wood supported by exterior foundation walls. Wood framing members, including wood sheathing, that rest on exterior foundation walls and are less than 8 inches (203 mm) from exposed earth shall be of naturally durable or preservative-treated wood.

 

[Mule]

Solid block wall, no wood.

 

[SCBO1]

Mule, did you see these sections,

2006 IBC 1803.3 & 1805.3.4

2006 IRC 404.1.6 & R401.3

pc1

 

[steveray]

This maybe....?

1805.3.4 Foundation elevation.

On graded sites, the top of any exterior foundation shall extend above the elevation of the street gutter at point of discharge or the inlet of an approved drainage device a minimum of 12 inches (305 mm) plus 2 percent. Alternate elevations are permitted subject to the approval of the building official, provided it can be demonstrated that required drainage to the point of discharge and away from the structure is provided at all locations on the site.

 

[Mule]

I've looked at those sections and really just don't know???????? The building is below the elevation of the street...

This is really a unique situation. We are building a new park, this is the restroom area with floor drains inside the restroom areas. However there is an electrical room adjacent to the restrooms. There is a screw-up on the plans by the engineer and architech where the sidewalks are shown to be at a specific elevation for accessibility and the foundation finish floor is at the same elevation. The exterior walls are block construction. The architect said we'll just leave the foundation where it is and we won't put a ledge on it for the block wall.

Soooo we have a foundation that is going to be at the same elevation as the grade around it. No drainage away from the building....water could possibly get into the building... Not so bad in the restroom areas since there are floor drains but there is a plumbing chase without floor drain and an electrical room with all of the electrical relays, lighting, basketball court lights, volleyball courts lights path lights, service panels... etc where you would have to program everything from the electrical room or perform maintenance that could become very wet........

 

[gbhammer]

Okay... 2009 IBC I thought there was a section of the code that specified that the foundation must be above grade by a minimum of 6". Am I going crazy or what? Is that still a requirement? Was it ever in the code?

This may have been where you got it from:

2003 IRC SECTION R319

PROTECTION AGAINST DECAY

R319.1 Location required. # 5. Wood siding, sheathing andwall framing on the exterior

of a building having a clearance of less than 6 inches (152mm) from the ground.

In the 2009 2009 IRC 317.1 #5

 

[gbhammer]

or maybe from here:

R320.4Foamplastic protection. In areaswhere the probabili-

ty of termite infestation is “very heavy” as indicated in Figure

R301.2(6), extruded and expanded polystyrene, polyisocyanu-

rate and other foamplastics shall not be installed on the exterior

face or under interior or exterior foundation walls or slab

foundations located belowgrade. The clearance between foam

plastics installed above grade and exposed earth shall be at least

6 inches (152 mm).

Around here most contractors just do it as a matter of practice, because we have both conditions.

 

[High Desert]

How are they going to provide for the sanitary sewer drainage?

 

[imhotep]

I've looked at those sections and really just don't know???????? The building is below the elevation of the street...This is really a unique situation. We are building a new park, this is the restroom area with floor drains inside the restroom areas. However there is an electrical room adjacent to the restrooms. There is a screw-up on the plans by the engineer and architech where the sidewalks are shown to be at a specific elevation for accessibility and the foundation finish floor is at the same elevation. The exterior walls are block construction. The architect said we'll just leave the foundation where it is and we won't put a ledge on it for the block wall.

Soooo we have a foundation that is going to be at the same elevation as the grade around it. No drainage away from the building....water could possibly get into the building... Not so bad in the restroom areas since there are floor drains but there is a plumbing chase without floor drain and an electrical room with all of the electrical relays, lighting, basketball court lights, volleyball courts lights path lights, service panels... etc where you would have to program everything from the electrical room or perform maintenance that could become very wet........

Have you looked at 1804.3 Site grading requirements? Are there sidewalks surrounding the structure?

 

[mtlogcabin]

If it is not to late just raise the floor elevation at least in the electrical room

 

[SCBO1]

Mule, it sounds like the way they design schools, keeps it cheep, then fix the water problem later when the water finds its way in.

Agree with mtlogcabin, raise the floor and ramp the sidewalks for ADA.

pc1

 

[Mule]

gbhammer, the IRC will not work for this structure since it is a commercial building.

HD, the sanitary sewer is below the building. This structure is built on a slope and they have excavated out according to the grading plans. Sanitary sewer will not be a problem.

imhotep, yes sidewalks surrounding the building with open air covers on two sides. I think 1804.3 will be my best shot at correction.

mtlogcabin, that was one thing we mentioned was to raise that area. We told the contractor to hold off on the building untill we figure out the best way to attack the problem.

Thanks for all the replies........... Just an FYI.... I posted this question on the "other" site that just opened back up and don't have a response yet!!

 

[Frank]

I've looked at those sections and really just don't know???????? The building is below the elevation of the street...This is really a unique situation. We are building a new park, this is the restroom area with floor drains inside the restroom areas. However there is an electrical room adjacent to the restrooms. There is a screw-up on the plans by the engineer and architech where the sidewalks are shown to be at a specific elevation for accessibility and the foundation finish floor is at the same elevation. The exterior walls are block construction. The architect said we'll just leave the foundation where it is and we won't put a ledge on it for the block wall.

Soooo we have a foundation that is going to be at the same elevation as the grade around it. No drainage away from the building....water could possibly get into the building... Not so bad in the restroom areas since there are floor drains but there is a plumbing chase without floor drain and an electrical room with all of the electrical relays, lighting, basketball court lights, volleyball courts lights path lights, service panels... etc where you would have to program everything from the electrical room or perform maintenance that could become very wet........

Architect designed it right--required by code

Floor level needs to be at same elevation as outside landing (Sidewalk).

2009 IBC 1008.1.5

"1008.1.5 Floor elevation. There shall be a floor or landing on each side of a door. Such floor or landing shall be at the same elevation on each side of the door. Landings shall be level except for exterior landings, which are permitted to have a slope not to exceed 0.25 unit vertical in 12 units horizontal (2-percent slope).

Exceptions:

1. Doors serving individual dwelling units in Groups R-2 and R-3 where the following apply:

1.1. A door is permitted to open at the top step of an interior flight of stairs, provided the door does not swing over the top step.

1.2. Screen doors and storm doors are permitted to swing over stairs or landings.

2. Exterior doors as provided for in Section 1003.5, Exception 1, and Section 1020.2, which are not on an accessible route.

3. In Group R-3 occupancies not required to be Accessible units, Type A units or Type B units, the landing at an exterior doorway shall not be more than 73/4 inches (197 mm) below the top of the threshold, provided the door, other than an exterior storm or screen door, does not swing over the landing.

4. Variations in elevation due to differences in finish materials, but not more than 1/2 inch (12.7 mm).

5. Exterior decks, patios or balconies that are part of Type B dwelling units, have impervious surfaces and that are not more than 4 inches (102 mm) below the finished floor level of the adjacent interior space of the dwelling unit."

Note that if the sidewalk beside the building is an accessible route it has a maximum cross slope of 1:48 --2003 A117.1 403.3

And a minimum slope away from the building for drainage of 2%

I hope your concrete guy is good to be able to fit between that min and max slope.

2009 IBC 1804.3

"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. "

 

[gbhammer]

Your right in this situation none of that would apply.

I figured you may have read the wording in the IRC for the 6'' above the ground protection and may have gotten the 6" thought from there.

The IBC has similar language about protection from decay for siding.

 

[Mule]

Frank, I can see that the architect designed it properly as far as the accessibility at the doors. The sidewalks should be even with the doors but I don't agree with the rest of the structure being at grade.

So what 1804.3 is saying is that all foundations shall be at grade level and the slope starts from that?????? Looks like a blowing monsoon would flood the interior of all buildings!

gbhammer, gotcha!!! I would be willing to bet you that that is where the 6" came in my old brain!!

 

[codeworks]

follow all of the above, we always put a 3-1/2 inch "housekeepin pad" in electrical rooms for all equipment to sit on. great discussion