# Rebar in contact with soil - gotta go?



## Darren Emery (Jul 6, 2020)

The vertical short bars stabbed in the ground are for chalk lines to guide the placement of wall forms.  If the soil contact rebar was in contact with the horizontal bars - no question, it would come out.  Wondering what others think of the presence of short rebar that will eventually rust out, but is not part of the true reinforcement?


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## Darren Emery (Jul 6, 2020)

Well... I thought I had figured out how to post a pic, but apparently not!   Is there a post that gives some guidance on how to upload a photo?  Could not find anything in the website discussion thread.


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## TheCommish (Jul 6, 2020)

as I understand it you need to be a Sawhorse to post a photo directly, workaround put in somewhere that has a link and post the link


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## ICE (Jul 6, 2020)

When steel rusts it expands.  That's not to say that it would cause the concrete in your case to crack.  A single rebar probably wouldn't matter much other than an impalement danger.  The rebars for strings are usually pulled out before the placement of concrete.


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## north star (Jul 6, 2020)

*+ & +*

Darren, ...in your photo it appears as though
the short pieces of rebar are indeed for the
string-lines.......IMO, the presence of "left
over \ non-removed material" indicates sloppy
work.......I would want them removed.

Are the 2" x 4" wooden forms for a sidewalk ?

Also, ...if you would like to be able to insert
photos in to Thread Topics, I encourage you
to become a Sawhorse by starting a subscription
to this "most excellent" Forum.......Send Jeff a
P.M.  for payment options.

Thanks !

*+ & +*


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## ICE (Jul 6, 2020)

north star said:


> *+ & +*
> 
> Darren, ...in your photo it appears as though
> the short pieces of rebar are indeed for the
> ...



I don’t see a picture.


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## north star (Jul 6, 2020)

*@ ! @*

ICE Man, ...at the end of Darren's OP, there is an
image Link.....I clicked on it and it took me to his
photo.

*@ ! @*


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## TheCommish (Jul 7, 2020)

The  link somewhat appears for me however it does not work


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## ICE (Jul 7, 2020)

It is there but it is not an active link for me.


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## mtlogcabin (Jul 7, 2020)

I right clicked the link and chose "open image in new tab" and it opened with no problems

Or the link below might work 

https://photos.google.com/share/AF1...?key=RFcteGZUSzVBYmtpUzByN1BQczczRVU4Z3FNOWl3


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## classicT (Jul 7, 2020)

Ask for it to be removed and move on...

For me, I prefer that it be removed, but if it isn't, I will not lose any sleep over it.

(Snip shot of the pic from the OP)


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## ADAguy (Jul 7, 2020)

Orange indicates "remove"?


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## Darren Emery (Jul 8, 2020)

Thanks for the input everyone.  I appreciate Ty posting the pic, and I will re-join as a sawhorse soon.  Was one of the original supports many moons ago - good to be back!


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## Darren Emery (Jul 8, 2020)

north star said:


> *+ & +*
> 
> Darren, ...in your photo it appears as though
> the short pieces of rebar are indeed for the
> ...



The forms are for spread footings under foundation walls.


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## Inspector Gift (Jul 8, 2020)

Darren's picture of the form boards for the footing is cause for my residential code question:

What is the maximum allowable space between the bottom of the concrete form and the ground?


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## JCraver (Jul 8, 2020)

ADAguy said:


> Orange indicates "remove"?



No.  In my area the soil is the same color as the rebar, so we paint the vertical bars so they don't get stepped on / tripped over.

I guess if we were in Cali., I'd have to write them up when they do that because there's no caps on top..


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## JCraver (Jul 8, 2020)

Inspector Gift said:


> Darren's picture of the form boards for the footing is cause for my residential code question:
> 
> What is the maximum allowable space between the bottom of the concrete form and the ground?




Depends on how much concrete you want to waste..

There's nothing in the IRC I don't think.  Maybe something in ACI 318?


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## Keystone (Jul 8, 2020)

Inspector Gift said:


> Darren's picture of the form boards for the footing is cause for my residential code question:
> 
> What is the maximum allowable space between the bottom of the concrete form and the ground?



I don’t have an ACI book and it’s been moons since I’ve thumbed through, I do recall when I was ACI 1&2 certified prior to ICC the formwork was to be in substantial contact w the surface.   I wouldn’t raise an eyebrow over a minimal gaps that won’t affect the overall sizing of the footing. And for residential most Crete for footings is poured stiff so the contractors can strip it soon after and move on.


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## Inspector Gift (Jul 8, 2020)

We limit gaps to no more than 2 inches between the earth and bottom of the form.   It was something we got from ACI 318 about the forms are required to *constrain* the concrete.   2018 IRC, Section 404.1.3.3.6 states the forms shall be approved material suitable for supporting and *containing* concrete.

I need to get a copy of ACI 332-14.


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## linnrg (Jul 9, 2020)

I do not have a problem with small rebar used as support - here is why.  Corrosion is not a fast action unless the right conditions exist (oxidation).  When you build large concrete structures (I have built footings that were 6' or more thick) you have form ties that are usually designed to shear off after removing the forms.  I built concrete caps that encased driven steel piles.  For exposed walls we usually rubbed the walls which would somewhat cover them) but to my memory we never did for the underground stuff.  In another post of days past I posted about the fiber rebar that we now see.  If that was used as support by being driven in the ground then I would likely let that go too.


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## TheCommish (Jul 10, 2020)

if is used chairs do they have to be isolated from the ground?


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## Mark K (Jul 10, 2020)

As long as the concrete flowing under the bottom of the forms does not disturb the concrete within the  forms it is not a code issues.  If there is a concern about a specific extreme case ask the engineer.

With regards to pieces of metal embedded in the concrete that are also in  contact with the ground I do not see a problem as long as they are not part of the required reinforcing.  If this is not acceptable then you should prohibit metal chairs for the rebar buy those chairs have been used for  years.


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## Msradell (Jul 10, 2020)

Mark K said:


> If this is not acceptable then you should prohibit metal chairs for the rebar buy those chairs have been used for  years.


Actually, chairs than that used in most cases to hold the bottom mat above the ground, in most cases, either small plastic chairs or dobies are used for that Mat and chairs a use top of that hold up the 2nd mat.

Here's an example of each: https://www.whitecap.com/dayton-superior-214-plastic-ez-chair-64406#127652-132PEZ225/, https://www.whitecap.com/dayton-sup...Ch0VtwQJEAQYAiABEgLoPfD_BwE#CPD075-132CPD075/


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## TheCommish (Jul 11, 2020)

I am aware there are nonmetal chairs, however, around here this is what is used

https://www.aftfasteners.com/produc...MJuWkWydn6WZ9nSRRIfi1BU3corYsXzxoCL4sQAvD_BwE


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## Msradell (Jul 11, 2020)

TheCommish said:


> I am aware there are nonmetal chairs, however, around here this is what is used
> 
> https://www.aftfasteners.com/produc...MJuWkWydn6WZ9nSRRIfi1BU3corYsXzxoCL4sQAvD_BwE


The only place I've seen those used around here are in highway construction. Just goes to shows it there different local standards in different parts of the country.


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## BJN (Nov 17, 2020)

I know - old thread. I’m seeing some rebar chairs made of wire that is stuck in the ground - basically a three sided wire square stabbed into the ground that the rebar sits on, usually used for footings. They are not made of rust resistant material, or protected in any way. Does that cause the rebar to rust? Is it a violation? I can’t find anything specific in the Concrete Manual or ACI 318.


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## Mark K (Nov 17, 2020)

As noted above metal chairs have been used for years


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## Pcinspector1 (Nov 17, 2020)

Would be concerned with mud on the rebar, which I'm seeing a lot more of lately.


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## BJN (Nov 18, 2020)

It’s kind of a small to worry about, even if it did cause rust, it might take 50 - 100 years before it matters. I just saw some of those wire chairs rusting in the back of someone’s truck, so I wondered.


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## ADAguy (Nov 19, 2020)

3" no?


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## BJN (Nov 19, 2020)

Yes, the chairs do hold the reinforcement 3” off the ground as required in IRC R403.1.3.5.3. This 3” minimum is so we don’t allow rebar to contact the earth, which would allow rust to eat the ground contact rebar and anything attached to it.
Which was why I wondered how mild steel wires in contact with the ground didn’t cause the same problem (although, the answer is probably that they are much smaller in diameter than No. 4 rebar.)


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## my250r11 (Nov 20, 2020)

BJN said:


> Yes, the chairs do hold the reinforcement 3” off the ground as required in IRC R403.1.3.5.3. This 3” minimum is so we don’t allow rebar to contact the earth, which would allow rust to eat the ground contact rebar and anything attached to it.
> Which was why I wondered how mild steel wires in contact with the ground didn’t cause the same problem (although, the answer is probably that they are much smaller in diameter than No. 4 rebar.)



Had an issue with an inspector many years ago on the metal chair in a 3' thick slab with 2 layers of rebar mats. He wanted us to remove the metal chairs and use the cmu rebar chairs. This slab was for a concrete tank an was 100' X 200'. This would require a lot of work to change and time & money. Called the structural engineer and he gave us a letter stating that the wire chair with or without sand plate will rust quickly which in turn causes the capillary break needed to stop the corrosion from continuing. That letter was given to the BO and was excepted. I have used that same mind set since. Just my 2 cents.


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## Beniah Naylor (Nov 20, 2020)

my250r11 said:


> Had an issue with an inspector many years ago on the metal chair in a 3' thick slab with 2 layers of rebar mats. He wanted us to remove the metal chairs and use the cmu rebar chairs. This slab was for a concrete tank an was 100' X 200'. This would require a lot of work to change and time & money. Called the structural engineer and he gave us a letter stating that the wire chair with or without sand plate will rust quickly which in turn causes the capillary break needed to stop the corrosion from continuing. That letter was given to the BO and was excepted. I have used that same mind set since. Just my 2 cents.


That is great information, thank you.


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## Beniah Naylor (Nov 20, 2020)

Not a huge concrete expert, and I see a lot of creative ways of suspending the rebar - not always sure how to handle that. Just because it's ugly and lazy doesn't necessarily make it a code violation...


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