# Drilling into footings



## S.U.M (Apr 17, 2013)

Hi All, 
Its been a while since I posted here so I am glad to be back, 

My topic is this, do you guys who do block foundations have any reservations about drilling into concrete footings?

We just completed a block job that called for the 15m rebar with a 2" bend at the end to be set into the concrete as it is poured every 16" vertically. The engineer didn't want it drilled in after incase the footing split, the footing was 20"x8"x 50'. All went well no issues,

Tomorrow we start another one that we didn't form or pour, the guy who formed and poured it didn't leave out the rebar like the drawings stated, 
I asked him why and he said he thought it would be easier for us to drill and epoxy them into place as we where building the first row.
I have done this before at 32"+ again it is a typical 20"X8" footing.

Do you think the footing could split with that many drill holes drilled in a straight line, I might even stagger the rebar so they aren't completely straight. 
Thanks
sum.

...should add both footings are reinforced with 15m (1st) and 20m (2nd) rebar horizontal.


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## slowsol (Aug 27, 2005)

No concern. 


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## Rio (Oct 13, 2009)

If you can stagger them why not?


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## greg24k (May 19, 2007)

It don't matter what we think... It could compromise the structural integrity or it could not, nobody knows or can predict this things. The question is "are you willing to gamble on it?"

If engineer said not a good idea, I'm sure there is a good reason for it.

With that said, I did a s^*t load of additions and I drilled into existing footing (most 10" deep) to epoxy in dowels 6" embedment, I never had an issue, but don't conclude anything based on that.

Good luck


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## Windycity (Oct 3, 2015)

Personally I prefer drilling and epoxying them in place. When the concrete guys pour the footing and place the rebar they never lineup with the cells of the blocks, when i drill it they are centered in the cell and line up for the next courses. I don't see any concern with cracking when you drill it because you're not driving the rebar in there, you are drilling a hole and placing the rebar in as opposed to driving it in. however if the engineer has concerns obviously follow his advice. 


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## brickhook (May 8, 2012)

We drill and epoxy ours.


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## JBM (Mar 31, 2011)

I used to charge 25 bucks per rod. I cant stand drilling the dowels personally, I would rather have a bunch of A's and O's on hand, which is infinitely faster and a better job then drilling. 

That said if you drill a 3/4 hole for a #5 bar it wont split. If you pound the fricken bejesus out of all the bars into a 5/8th hole, I dunno, it wont split either but I could see someone who thinks to much thinking it may.


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## MikeFL (Oct 7, 2016)

You should consider doing your own footings. When the guy doing the footing is not laying the block he doesn't care how out of level it is or whether anything works right for you.


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## jomama (Oct 25, 2008)

It really depends on what you're building.

On home foundations/additions, we almost always drilled them in after the first course. After bowing once to an employee, who insisted we'd save ton's of time by setting them into the footing right away, and then having to saw the webs out of 2/3's of the block on the first course, I definatley have a bias. Drilling time and pounding is negligable, and you can be certain that you have the rod in the correct place when it comes to grouting. Not to mention, on a basement, the rods aren't doing much at all once the floor is poured.

If you're talking about a retaining wall, I'd want to cast them into the footing more-than-likely, but you need to do so precisely.

If you're running into an engineer that thinks a footing's going to crack from drilling and epoxying dowels into it, he probably is a little out of his element............


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## S.U.M (Apr 17, 2013)

Windycity said:


> Personally I prefer drilling and epoxying them in place. When the concrete guys pour the footing and place the rebar they never lineup with the cells of the blocks, when i drill it they are centered in the cell and line up for the next courses. I don't see any concern with cracking when you drill it because you're not driving the rebar in there, you are drilling a hole and placing the rebar in as opposed to driving it in. however if the engineer has concerns obviously follow his advice.
> 
> I agree 100%, I much prefer this way of doing it, the one engineer just got me thinking about it,


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## S.U.M (Apr 17, 2013)

MikeFL said:


> You should consider doing your own footings. When the guy doing the footing is not laying the block he doesn't care how out of level it is or whether anything works right for you.


I do them most of the time but to honest I like when they are in, poured and striped so we can just get moving when we arrive.


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## fjn (Aug 17, 2011)

I don't get all this talk of missing the cells in block. We have built a bunch of buildings using General Shale's Super King structural brick. The cores are only 3.5" x 3.5" and we never had a problem .Not to be a wise guy but can't anyone read a ruler ? That is all it takes.


Batter boards,string lines and a good 100' tape.We stick straight pins into the string lines to identify where the rods need to be,drill a hole in a 1" x 4" and nail it across the form boards,tie the J hook to the continuous footing bars and pour away. If anyone is trying to muck the bars in while the pour is going on,you are shooting yourself in the foot. 


Plus,inspectors around most places who have an awareness of the proper way to do it will NOT even allow simple anchor bolts to be mucked in,they need to be positioned BEFORE the pour. Reason being,placement accuracy and proper encapsulation of J hook on bolts. And that is for a simple little hook on 1/2" bolt !


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## fjn (Aug 17, 2011)

Here is a little dialogue regarding "sticking stuff" into wet concrete.


http://www.eng-tips.com/viewthread.cfm?qid=308093


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## superseal (Feb 4, 2009)

Two towns close to me will not allow wet set rebar...you'll be flagged at prepour and zinged for another inspection.


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## MikeFL (Oct 7, 2016)

superseal said:


> Two towns close to me will not allow wet set rebar...you'll be flagged at prepour and zinged for another inspection.


When I was an inspector I had no problem letting them tie them to the horizontal bars and leaning them against the form and swinging them vertical as they poured. But if they're not tied at time of inspection, I'm not signing off.


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## sunkist (Apr 27, 2012)

MikeFL said:


> When I was an inspector I had no problem letting them tie them to the horizontal bars and leaning them against the form and swinging them vertical as they poured. But if they're not tied at time of inspection, I'm not signing off.


I'm with mike on this here in FL we tie off to the bars in the footer, the only time i drill and epoxy if the slab is pre-existing, 3/4 drill 5/8 rod 6 inch enbedment 16" on centre.


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## JBM (Mar 31, 2011)

I believe in Fl, at least Indian River, you couldnt have a span of somewhere around 7' without a bar or thereabouts. 16 oc seems a bit overkill.


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## MikeFL (Oct 7, 2016)

JBM said:


> I believe in Fl, at least Indian River, you couldnt have a span of somewhere around 7' without a bar or thereabouts. 16 oc seems a bit overkill.


7' you might be thinking about that 3rd bottom bar in a tie beam over a door opening >7' wide.

16" o.c. is pretty standard for grouted fill cells.
Check out this video: 



If the fill cells are 7' o.c. that wall is never going to stand up.


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## JBM (Mar 31, 2011)

MikeFL said:


> 7' you might be thinking about that 3rd bottom bar in a tie beam over a door opening >7' wide.
> 
> 16" o.c. is pretty standard for grouted fill cells.
> Check out this video: https://www.youtube.com/watch?v=rTHehy84XJs
> If the fill cells are 7' o.c. that wall is never going to stand up.


I was a licensed masonry contractor and build hundreds and hundreds of sfh with 8" cmu, I assure you the rules I had to follow were something like I stated. It may have been 4', but I think it was 7. They also required double beam courses, which might or might not mean anything. Although in port st. luci they did one beam course with a #6 bar in it, with the same downrod spacing. 

That video would mean something if it had verticle and horizontal re-enforcement somewhere between the target. As someone who has taken a sledgehammer to many walls with re-enforcement, I wished the walls would shake apart like that. 

I do basement rebuilds here every once and a while and for earth retention the white shirts usually spec it at 32 o.c.


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## kapena (Aug 20, 2004)

MikeFL said:


> 7' you might be thinking about that 3rd bottom bar in a tie beam over a door opening >7' wide.
> 
> 16" o.c. is pretty standard for grouted fill cells.
> Check out this video: https://www.youtube.com/watch?v=rTHehy84XJs
> If the fill cells are 7' o.c. that wall is never going to stand up.


That CMU wall sure does not look to be grouted in the video, so I consider that video to be a bogus comparison.


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