Doing rebar for footing

[Jared Drake]

I'm finally at the place where we can start seriously planning our cabin and I'm figuring out what I can and can't do on my own. I can hand dig our footing but I'll leave the concrete pouring to the cement plant. However, I'd like to try the rebar on my own but can't find anything really helpful on youtube about how to do it or how much to use. Our depth here is 16", so I've got that to work from. Can anyone help?

[rick91351]

Jared are you looking to pour a footings and walls or piers and post?

I can talk you through footings and walls and rebar.  I really have no experience with piers and post.

[Squirl]

Technically, legally, none is required by code.  It doesn't mean that it isn't a good idea.

Two #4 down the center is most common and in all the books I read.



I used concrete bricks to hold up the rebar.  The concrete stands from the store sucked and kept falling over.

Overlapped and tied at the corners.



The concrete truck was able to drive the chute around and drop in strait in the form.





Tamp and screed.

[rick91351]

Technically your corners are incorrect and the wood holding up the rebar wrong and the two pieces of rebar I see extending to the forms are all wrong as well.

All that said I don't think I would lay awake at night worrying about  that.   

My shop photo shows - Technically rebar has to sit in chars that will not act as a conduit for moisture,  or be suspended from the top of the form down via tie wire.  Per the electrical code at the time I ran my grounding wire to the rebar and connected the ground to a frost free as well.





Where your corner is you do not meet it there but actually turn the corner and splice at least 30 X's the thickness of the rebar for 2500 lb concrete.  There are versus charts a available in the net that show proper splicing lengths.  This prevents touching the end of the forms and causing conduit moisture to the rebar and give the whole bar more strength.

Code says something to the effect

"A lap splice is when two pieces of rebar are tied together where the bars overlap. The length of the overlap is calculated by using the equation 30 times the bar diameter. A minimum of four sets of ties are then evenly spaced along the lap length."

So you turn the corner and make your splice.  Now I think if you weld them that does not apply if I remember correctly or if you use these funky rebar couplers that attach a collar with a lot of pressure and you only see them in high $ commercially engineered jobs.

Mechanical splices use metal channel devices to connect two pieces of rebar. Typically, the rebar must have threaded ends to fit into the mechanical splice and then the splice is tightened onto the bar. Lentons and couplers are common names used to refer to mechanical splices. This splice is used for bars too large for lap splicing or, in situations in which the splice may have to be undone at some later point, such as when connecting a column to a setting rig.

Proper corner note the splice out side run near corner.



Note the verticals for the walls wired to the footing rebar and the the first run of the horizontal rebar.  We did not use any chairs here on this job in the footing but suspended it all from the footing forms.  Note the string line used to keep distance in the verticals so they will not touch and lined up properly for when we set the walls.



I did slip in some chairs under these pier rebar cages because it seemed easier than suspending them. 



This is only about half the rebar that was required to go in to our home



This is a cheap rebar cutter and bender that works well with 3/8 and half inch rebar.  5/8 even gives the big commercial cutter and benders a work out.  Just a side bar if 5/8 is required a person might want to look at buying them cut and bent at the jobber.  Long bars are bent as you place then in the forms.  measure and allow for the bend and the joint laps mark the bar and go to the bender.     



Most of the verticals and horizontals cut and bent for the house.

 

Photos shown is our house and shop.  I was working with Mike Taylor a concrete / building contractor who actually hired me to work for him.  I got my experience not long after a couple years of collage and discovered higher education and I were  Well it was not for me..... 
       
   




     

[rick91351]

   Squirl ol buddy - ol pal wish to stand corrected and print a retraction.  You used cement bricks not wood to hold up the rebar.  I have not researched to find out if that is codified or not.  I will give it to you however.  But my little plastic chairs are cheaper than your bricks.    

[Squirl]

  Squirl ol buddy - ol pal wish to stand corrected and print a retraction.  You used cement bricks not wood to hold up the rebar.  I have not researched to find out if that is codified or not.  I will give it to you however.  But my little plastic chairs are cheaper than your bricks.   

I bought the little plastic chairs. They kept tipping over on me.  They never would have held up during the pour.   The ones you have look better than the ones they sold around me. I had to run out and buy the concrete brick.  Considering footings are allowed to be made from unreinforced mortared concrete blocks and rebar wasn't required, I wasn't worried.  I also hung them from wire. 

Your footing is definitely more professional.  I had never seen the grounding wire used in any of the publications I had read.

I must print a retraction as well.  I said that rebar isn't required by code.  It is in certain areas. Maybe.

Concrete footings located in Seismic Design Categories D0, D1 and D2, as established in Table R301.2(1), shall have minimum reinforcement. Bottom reinforcement shall be located a minimum of 3 inches (76 mm) clear from the bottom of the footing.

http://publicecodes.cyberregs.com/st/ny/st/b400v10/st_ny_st_b400v10_4_sec003.htm

However, it does not state what "minimum reinforcement" is.  The rest of the section only refers to vertical rebar to tie the wall to the footing, and the section might only refer to vertical rebar.

[rick91351]

.......snip.........

I had never seen the grounding wire used in any of the publications I had read.

...........snip..............

It only worked there because of the tie in with the 'frost free' hydrant that comes up into my shop through the footing.   It is like a five foot frost free and buried below the frost line.  You can not normally do that and only where there is a metal water pipe.  ie the frost-free.  A footing is not a recognized conductor and hopefully will not get wet enough to become a conductor.  Only reason I even wrote anything about it was I was concerned some one might see it and wonder what the wire is doing there or do something unsafe.        

[Jared Drake]

Thanks for the replies. Our county has adopted the 2006 IBC, so if it doesn't require any rebar in the footing, then I'm not putting any there. I just always assumed it HAD to be there.

[Squirl]

Thanks for the replies. Our county has adopted the 2006 IBC, so if it doesn't require any rebar in the footing, then I'm not putting any there. I just always assumed it HAD to be there.

I don't know what seismic area you are located in. Eastern Arkansas is listed as a high seismic zone.



Rebar is a good idea in concrete, even if not required.  It can add tremendous strength for the least amount of money.  20 ft rebar was $7 a piece.  So it cost $70 for my entire footing.

[rick91351]

Couple observations.  Rebar pays of big time.  Even is not properly installed.  It adds strength to concrete - most of us or our dwellings - will never go through a major earthquake.  But most will go through improper compacted soils and fills settle, this causes cement to crack.  Most will go through large swings in ground water between drought and feast years, cold and warm years.  This all effects concrete because of the soil it rests on.  I would also like to cite the new problem of fracking and its associated problems.  I have a cousin who lives near Ok City and her home two years ago was like in an earthquake zone..... Denver because of deep well injection of some highly suspect US Government waste had earthquakes by the dozens suddenly.  They stopped pumping and the quake quit.       

Sort of strange I had our house - the one shown engineered.  We are in the same earth quake zone as you if you are by the way yellow.  By code we are not required rebar as well.  Code is the least allowable thing you can do per the law.  Most people can stand on its built to code and smile and feel warm and fuzzy.  With it not even hitting home that is the least allowable.  Sort of like the government is going to save my home.

Guess what the engineer required?  Three bars of #5 rebar or 5/8  and a footing 12 inches deep and 30 inches wide and six bag mix.  Rather than 8 inch by 20 inches and five bag mix.  He also required almost a third more verticals of #4 rebar.  I was really expecting him to add another run of #4 in the walls.  If he would have I would not have thought twice but gladly added it.

I have seen too much stuff built for the moment with no intent of passing it along or having it stand for a hundred and fifty to two hundred years.  HUD Houses I worked on almost 40 years ago are reaching the ends of their life or have reached the end of their life.  Yet stuff my uncles built or worked on are still going eighty to hundred years latter.

Just some thoughts..... Rick       

[UK4X4]

put in the rebar.....! you can never have enough !

Mine is on 48" of crushed rock and its all No5 rebar we had to hammer in small lengths of rebar to support the weight of the metal, the little stands just crushed

My foundation is over built- I expect it to last at least two generations and stay in 1 piece

Even if I built a perimeter foundation I would run rebar - it multplies the strength of the concrete - keeping the foundation in 1 piece even when you have diferent ground support strengths- especially on a shallow foundation.

Yes the corners need to overlap - mine were 36" overlaps on all the corners

[Redoverfarm]

Whether it is required or not I would use some rebar in the footings.  It is a small price to pay for something that may be needed later.  By that I mean that this earth is constantly changing.  Plenty of locations are experiencing problems that they never envisioned to occur before.  It may make a difference between a cracked footing that could ultimately transfer to window alignment, drywall cracks and the like.  Just my $.02 worth.