# Boring Holes in Cinderblock Wall - Codes



## macmikeman

It's fine in the other 49 states, California it probably releases cancer causing dust particles into the air putting undocumented workers and their large families at risk.


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## Southeast Power

RickM15752 said:


> I'm bidding on a job to install security and surveillance systems in an industrial building which has a cinderblock wall separating the main area from the server room. I'll need to bore some holes through the cinderblock. The data installer will need to do the same, so there will be a few holes. I estimate I'll need 4 2" holes, might get by with just 3 2". I might go slightly larger in case I need to sleeve the hole and pack it with intumescent.
> 
> Is there a code that addresses the hole pattern in a cinderblock wall? Horizontal versus vertical? Hollow versus filled? I'm sure the Data installer will be putting a few more holes than I will and I don't want to violate a spacing code. I don't know if the block wall if filled with concrete and rebar either. I know to stay away from the center and ends of the block as that is where the block webbing structure is located. What reference would contain the code on something like this?


You can go through the webs just fine or you can remove an entire block.

Nothing is stick built here. Every exterior wall is CBS, some interior walls are partition block. Ive never had anyone mention anything about spacing hole.
Also, you can core right through the webs too.


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## splatz

Nobody really worries about it, but with brick / block construction, if you take out enough horizontally, you need a lintel installed to carry the weight or the sag above can cause cracks. This is more of a concern for cutting a window or door in a block wall than drilling holes for conduit, but if you compromised enough, you'd probably want to get an engineer involved. If you ran a horizontal rack with several feet of closely spaced pipe, yeah I could see that being a possible issue. 

Just for nice workmanship, I don't make my holes any bigger than they need to be, and I firestop with this stuff, which is stronger than the red: 

http://www.3m.com/3M/en_US/company-...r-Sealant-IC-15WB?N=5002385+3293123898&rt=rud 

With this stuff filling the gaps the hole is filled with something as rigid as the material you removed, so I doubt there would ever be a problem. 

(As always, technically you should make sure the rating is adequate for your requirements, the yellow is three hours and the red is four hours, but I've never heard a peep about it.)


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## drsparky

1. Check to see if is a fire rated wall.
2. Have a coring company cut the holes.


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## telsa

drsparky said:


> 1. Check to see if is a fire rated wall.
> 2. Have a coring company cut the holes.


Dittos.

Dump such a headache onto a sub.

There is NO WAY you're going to compete with those players.


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## splatz

drsparky said:


> 1. Check to see if is a fire rated wall.
> 2. Have a coring company cut the holes.





telsa said:


> Dittos.
> 
> Dump such a headache onto a sub.
> 
> There is NO WAY you're going to compete with those players.


I might agree in that if the OP has to ask this question they might as well pay someone to install sleeves. I'd also bet the OP could use some help sizing these and doesn't know the guidelines for conduit fill. 

Otherwise, why would you farm out something so small? Two or three small holes in block is nothing, no special tools needed, we're talking about 15 -
30 minutes of work.


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## Glock23gp

splatz said:


> I might agree in that if the OP has to ask this question they might as well pay someone to install sleeves. I'd also bet the OP could use some help sizing these and doesn't know the guidelines for conduit fill.
> 
> Otherwise, why would you farm out something so small? Two or three small holes in block is nothing, no special tools needed, we're talking about 15 -
> 30 minutes of work.


Agreed. I have a rotohammer and core bits in my van at all times. Why would you farm out your own work? Especially so small of job as stated....?

Sent from my SAMSUNG-SM-N910A using Tapatalk


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## MechanicalDVR

Welcome aboard @RickM15752!

I wouldn't stress the holes you are looking to make damaging anything. As others said you could pop out a whole block with no problem.


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## sbrn33

Hell it is cinder block you can go thru that with your linesmans.


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## John Valdes

sbrn33 said:


> Hell it is cinder block you can go thru that with your linesmans.


Right on.
My preferred method is the round end of a ball pean hammer.
I can make a almost perfect hole in the web with one.
The trick is to make sure you go through the open web. Its easy and its fast.

I have never used a drill of any sort on cinder block walls.
You pop your hole on one side. Note the exact block and exactly where the hole is and pop out another hole perfectly.

I can do this with 1/2 inch and get a great fit or a loose fit. 2 inch would be so simple and easy.
I also concur on removing the complete block. In situations where you need more room.


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## MechanicalDVR

John Valdes said:


> Right on.
> My preferred method is the round end of a ball pean hammer.
> I can make a almost perfect hole in the web with one.
> The trick is to make sure you go through the open web. Its easy and its fast.
> 
> I have never used a drill of any sort on cinder block walls.
> You pop your hole on one side. Note the exact block and exactly where the hole is and pop out another hole perfectly.
> 
> I can do this with 1/2 inch and get a great fit or a loose fit. 2 inch would be so simple and easy.
> I also concur on removing the complete block. In situations where you need more room.



Lol, I love the ball peen method, quick fast and simple! :thumbsup:


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## sbrn33

John Valdes said:


> Right on.
> My preferred method is the round end of a ball pean hammer.
> I can make a almost perfect hole in the web with one.
> The trick is to make sure you go through the open web. Its easy and its fast.
> 
> I have never used a drill of any sort on cinder block walls.
> You pop your hole on one side. Note the exact block and exactly where the hole is and pop out another hole perfectly.
> 
> I can do this with 1/2 inch and get a great fit or a loose fit. 2 inch would be so simple and easy.
> I also concur on removing the complete block. In situations where you need more room.


Don't you love it when it is filled and you didn't know it?


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## John Valdes

sbrn33 said:


> Don't you love it when it is filled and you didn't know it?


I have had that happen. But very rarely. I usually tap on the block to make sure its open.
If its filled, you can tell on the first strike.
If you have to, you can drill a small pilot hole. This verifies its clear and also helps you to tap out the hole.

I know others that do drill the pilot hole anyway. I was taught to drill a pilot hole. But found out on my own its not necessary.


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## sbrn33

John Valdes said:


> I have had that happen. But very rarely. I usually tap on the block to make sure its open.
> If its filled, you can tell on the first strike.
> If you have to, you can drill a small pilot hole. This verifies its clear and also helps you to tap out the hole.
> 
> I know others that do drill the pilot hole anyway. I was taught to drill a pilot hole. But found out on my own its not necessary.


No I meant with that powdered insulation. You make your hole not thinking anything and all of a sudden that **** just comes pouring out with no way to stop it.


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## RickM15752

Wow, I didn't think I'd get such great replies so soon. Thank you to all. I do know about conduit fill codes and like to do larger conduit for future expansion. In reality 2 2" holes will handle my wire requirements within code, but I may do 3 holes. When doing a walk through for bidding I did not check whether the wall was hollow or filled. This wall separates two tenants, and the server room of my customer is actually within the envelope of the other tenant's building. So, I'm assuming it's a filled fire wall. Either way, I can bore the holes myself and can handle the fire/smoke blocking too. My concern was about structure, I haven't had to bore large multiple holes in cinder block walls, usually I only need to do 3/8" or 1/2" to run one wire through this wall type.


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## just the cowboy

*To the OP*



sbrn33 said:


> No I meant with that powdered insulation. You make your hole not thinking anything and all of a sudden that **** just comes pouring out with no way to stop it.


Pay note to this, It is called Vermiculite and flows like water. Have a caucking gun ready with the end cut large, if stuff starts flowing out cover with hand and pump half a tube in hole between fingers. It will not stop on its own.


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## RickM15752

Once, when drilling a 3/8" hole in a hollow perimeter cinder block wall for a Cat 6 (camera location) the bit hit what appeared to be heavy paper, like an empty cement bag. I usually stop the drill when it penetrates into a hollow area and push until it stops against next point where I need to drill. I used a smaller bit to probe but found nothing but paper. The smaller bit pushed the obstruction clear and I drilled through. I take care when drilling into any wall, concerned about hitting pipes and wires, so this caused me some concern.


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## telsa

All of the above posts assume that the project can tolerate the ultimate in "hammer drilling." ( Heh )

When you're punching through a Legally Demising Wall -- that is certainly fire rated -- in a commercial build -- like HECK you're going to be allowed to 'get sloppy' -- and quick.

I'd have a totally different 'take' on this if this were otherwise.


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## RickM15752

To update my project, I just got back from the job site, took another look and decided to relocate my main alarm panel and my NVR to a secondary server room that does not require large holes through the cinder block wall. I examined the cinder block wall, which has a door cut out, no door or jamb, and I see where rebar, perpendicular and horizontal, was cut for the door opening. And, it is filled with concrete. The only wire I need to feed through is a 4 conductor, 22 ga. cable. The data installer has to bore the holes for the network and telephone, so I'll be getting away cheap on this wire run.


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## telsa

RickM15752 said:


> To update my project, I just got back from the job site, took another look and decided to relocate my main alarm panel and my NVR to a secondary server room that does not require large holes through the cinder block wall. I examined the cinder block wall, which has a door cut out, no door or jamb,* and I see where rebar, perpendicular and horizontal, was cut for the door opening. And, it is filled with concrete.* The only wire I need to feed through is a 4 conductor, 22 ga. cable. The data installer has to bore the holes for the network and telephone, so I'll be getting away cheap on this wire run.


Call me totally unsurprised.


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## RickM15752

I meant to write vertical and horizontal rebar, not _perpendicular and horizontal_. But, you got the point.


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## sbrn33

telsa said:


> All of the above posts assume that the project can tolerate the ultimate in "hammer drilling." ( Heh )
> 
> When you're punching through a Legally Demising Wall -- that is certainly fire rated -- in a commercial build -- like HECK you're going to be allowed to 'get sloppy' -- and quick.
> 
> I'd have a totally different 'take' on this if this were otherwise.


Be honest, you have really never done any work in the field have you?


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## telsa

sbrn33 said:


> Be honest, you have really never done any work in the field have you?


Sab...

Now even *I* am embarrassed for you. 

You've gone full re tard.


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## Southeast Power

Glock23gp said:


> Agreed. I have a rotohammer and core bits in my van at all times. Why would you farm out your own work? Especially so small of job as stated....?
> 
> Sent from my SAMSUNG-SM-N910A using Tapatalk


They are stick built guys.
We have everything we need to make holes in block, its called a hammer. Very fast and easy to do.
As for coring, we do all of our own.
I would only sub out deep saw cuts as cut and remove or holes bigger than what Sunbelt can rent us.


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## Jlarson

I'll core, cuts I sub too.


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