250.52---2008 code

[overfieldb]

My co-worker and I don't agree on this revision. The change states the conctete encased electrode located horizontally near the bottom or vertically and within the portion of a concrete footing or foundation in direct contact with the earth. He thinks that the electrode can be in the stem wall, I think it should be in the footing. What is your opinion?

 

[raider1]

My opinion is that your co-worker is right, if the stem wall is in direct contact with the earth.

The addition of "or vertically, and within the that portion" seems to clarify that the CEE can be a vertical section of re-bar as long as it is within the portion of the foundation that is in direct contact with the earth.

This section includes the terms footing and foundation so the CEE can be in either the footing or foundation.

Chris

 

[tlaidman]

the concrete and rebar must be in contact with the earth for a minimum of 20feet. Check the cod under ufer ground

 

[overfieldb]

250.52

250.52

As I read the code: the ufer must be located near the bottom and in direct contact with the earth. How would a stem wall be in direct contact with the earth if the pour of concrete of the footing and stem wall are at different times and the stem wall is setting on the footing. It would be in direct contact with the dirt on the sides of the wall but not on the bottom as the code states. Am I wrong ?

 

[Wes G]

It would appear to me that the distinction drawn by this wording is that whether in a footing or in a stem wall, the area counted as an electrode needs to be in direct contact with the earth. The footing or stemwall rebar would want to be as low as practicable because the moisture content that makes the electrode effective will be higher when not directly exposed to the air.
IMO it appears obvious that the portion of the stem wall that extends above the surface of the earth would not qualify
___________________
Wes Gerrans
Electrical Technology Instructor
Northwest Kansas Technical College
Goodland, KS

 

[raider1]

As I read the code: the ufer must be located near the bottom and in direct contact with the earth. How would a stem wall be in direct contact with the earth if the pour of concrete of the footing and stem wall are at different times and the stem wall is setting on the footing. It would be in direct contact with the dirt on the sides of the wall but not on the bottom as the code states. Am I wrong ?

With the addition of "or vertically, and within that portion" makes the intent clear that, a 20' vertical section of re-bar, within a stem wall of a foundation that is direct contact with the earth, is to be considered a CEE.

Chris

 

[barbeer]

I agree with Chris, assuming the steel is tied, ALL steel acts like 1 piece and is connected from top to bottom. Assuming there is even steel in the stem wall!:roll:

 

[raider1]

I agree with Chris, assuming the steel is tied, ALL steel acts like 1 piece and is connected from top to bottom. Assuming there is even steel in the stem wall!:roll:

It is amazing to see how different construction is in other areas. In my area you won't find a foundation that doesn't have at least 20' of #4 re-bar installed and tied to the footing steel. The typical 8' foundation wall will have #4 re-bar installed at 24" centers vertically and at least 6 #4 re-bars installed horizontally and all tied together with in the concrete wall.

Chris

 

[gndrod]

It is amazing to see how different construction is in other areas. In my area you won't find a foundation that doesn't have at least 20' of #4 re-bar installed and tied to the footing steel. The typical 8' foundation wall will have #4 re-bar installed at 24" centers vertically and at least 6 #4 re-bars installed horizontally and all tied together with in the concrete wall.

Chris

Chris,

UBC and IRC require minimum #3 rebar in vertical stemwalls in most cases. A GEC footer connection through the vertical #3 is not NEC code compliant even though the 2008 NFPA 70 states allowing vertical to be connected to the #4 footer Ufer. In most residential, few stemwalls are over 4' high to require 24" oc vertical rebar. Of course using #4 is predicated on other areas as you stated and the #3 NEC non-compliance will probably be overlooked for a while. rbj

 

[infinity]

It is amazing to see how different construction is in other areas.
Chris

You're right different locales do things differently. Around here almost all foundations are built out of concrete block. The footing is poured first then the masons lay the block on top of the footing. If you're lucky the footing has #4 or larger rebar. Some don't, therefore the CEE is not required.

 

[raider1]

Chris,

UBC and IRC require minimum #3 rebar in vertical stemwalls in most cases. A GEC footer connection through the vertical #3 is not NEC code compliant even though the 2008 NFPA 70 states allowing vertical to be connected to the #4 footer Ufer. In most residential, few stemwalls are over 4' high to require 24" oc vertical rebar. Of course using #4 is predicated on other areas as you stated and the #3 NEC non-compliance will probably be overlooked for a while. rbj

I agree,

My point was that if we have 20' of #4 rebar within the stem wall that is in direct contact with the earth then that is to be counted as a CEE.

I live in a high seismic zone and #3 rebar is not permitted for reinforcing within concrete footings and foundation walls, we are required to use a minimum of #4 rebar.

Chris

 

[iwire]

Whats a 'stem wall'?

I have never heard that term used in this area.

 

[stickboy1375]

Whats a 'stem wall'?

I have never heard that term used in this area.

A stem wall anchors a home’s foundation firmly in the ground, working like roots to hold a house down and tie it into the ground below.

They marry the slab to the foundation and the walls to the slab and stem wall. The pour itself is continuous, which means that it is seamless. As a result there is no seam between the stem wall and the slab. There is no seam where water can enter and weaken the connection between the stem walls below ground and the slab on grade or the walls that are anchored into the slab.

 

[George Stolz]

Got a picture?

 

[stickboy1375]

 

[iwire]

They marry the slab to the foundation and the walls to the slab and stem wall. The pour itself is continuous, which means that it is seamless. As a result there is no seam between the stem wall and the slab. There is no seam where water can enter and weaken the connection between the stem walls below ground and the slab on grade or the walls that are anchored into the slab.

Thanks, that was a good description.

A stem wall anchors a home?s foundation firmly in the ground, working like roots to hold a house down and tie it into the ground below.

I thought that was what the basement walls do.

 

[macmikeman]

Whats a 'stem wall'?

I have never heard that term used in this area.

As I read thru page one, I kept thinking the same thing, and also I was thinking these guys are going to murder me if I have to ask what a stem wall was. Glad it was Bob instead of me.

 

[stickboy1375]

Were just used to calling them basement walls around here...