# Hammering holes in block



## mk2munky

Of course, there are cleaner ways to make holes in block, but I was using my hammer to bust a hole today to nipple a pipe through. The customer, a guy from the school district, told me I wasn't allowed to do that because it makes microfractures in the block.

I understand what he's saying, but has anyone else ever heard this and is this THAT serious of an issue?


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## walkerj

You are a butcher for that. 

You will take out the whole wall if you aren't careful.


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## ponyboy

wow thats a new one. so how do you determine where to bash the other side of the wall since youre too lazy to get a drill out


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## Celtic

walkerj said:


> You will take out the whole wall if you aren't careful.


Does it matter how big the wall is?
:jester:


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## Southeast Power

mk2munky said:


> Of course, there are cleaner ways to make holes in block, but I was using my hammer to bust a hole today to nipple a pipe through. The customer, a guy from the school district, told me I wasn't allowed to do that because it makes microfractures in the block.
> 
> I understand what he's saying, but has anyone else ever heard this and is this THAT serious of an issue?


Interesting dear sir. I would like to become more informed on the matter. Could you kindly provide me with such reference materials?


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## xlink

Of course, a hammer drill would never fracture or loosen a block.


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## B4T

You first have to know if the block is two cell or three cell.. unless you want a much bigger hole than needed..


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## drumnut08

mk2munky said:


> Of course, there are cleaner ways to make holes in block, but I was using my hammer to bust a hole today to nipple a pipe through. The customer, a guy from the school district, told me I wasn't allowed to do that because it makes microfractures in the block.
> 
> I understand what he's saying, but has anyone else ever heard this and is this THAT serious of an issue?


Are the block walls load bearing ( no steel skeleton ) ? I could see it being an issue if they are . Not very typical in construction these days , and if the walls are load bearing , they usually fill the cells solid , so you can't beat a hole through . I've seen guys do some unnecessary damage with a hammer , lol !


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## mk2munky

As I stated, I realize there are better, cleaner ways to make holes, but my experience has been that the foreman doesn't always provide the right tools, i.e. the right sized bit. Additionally, being an apprentice, it's best to do as the journeyman tells you.

Now that I've defended my methods, back to the topic.

A quick search on Google, I wasn't able to find anything specific on the issue, which is why I asked if anyone else has ever heard this.

After this all happened, my foreman told me he had been informed on the issue earlier on in the job before I had gotten there and that technically a hammer drill wouldn't be good enough, but a dry core drill would be most ideal.

I think the bottom line is that he is being a little overly protective, but I guess that's his prerogative as the customer.


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## mikeh32

get a star bit if you are that cheap. dont be a hack.


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## Spunk#7

How about a Dry Core bit on a 7" grinder,works great for me!


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## mk2munky

mikeh32 said:


> get a star bit if you are that cheap. dont be a hack.


Do you understand the topic?



Spunk#7 said:


> How about a Dry Core bit on a 7" grinder,works great for me!


Apparently that's the ideal, I was just wondering if this microfractures thing has any merit.


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## ponyboy

mk2munky said:


> Do you understand the topic?


Yeah. You don't have the tools or know how to make simple holes in block walls so you beat it with a hammer. Your question is will it weaken the wall, my honest answer- I don't know but I don't use a hammer to make holes so I don't have to worry about it


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## JourneymanInTraining

My boss has instructed me(also an apprentice) to make holes in block walls with a hammer. I don't like it much, but like you, I tend to follow the instructions given to me by my journeyman and/or the guy who signs my cheque, with a few exceptions("No, you cannot borrow my screwdriver, there's a padlock on my toolbox to keep you OUT."). I've revisited areas where we've done that several times, and seen hammer-made holes several years old, that don't show any signs of additional cracking or anything like that. I actually saw a guy chip out an entire block and run a cable tray through the empty space(not our company). Looked ugly as hell, but it doesn't show any signs of cracking or sagging or anything.

I'd be interested to see conclusive information that says it compromises the structure. I couldn't say with any certainty. I'll check back later to see if anyone has anything.


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## BBQ

ponyboy said:


> Yeah. You don't have the tools or know how to make simple holes in block walls so you beat it with a hammer. Your question is will it weaken the wall, my honest answer- I don't know but I don't use a hammer to make holes so I don't have to worry about it


Sorry you are so unskilled, I learned how to make clean holes in block with a hammer my first weeks in the trade.


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## Southeast Power

It's very rare to find a building here that is not CBS (CMU) construction.
I have never heard of the "micro fracture theory" I think your guy has way too much time on his hands or, is parroting some BS he heard in a bar somewhere.


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## TOOL_5150




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## chewy

I'd think you were a knuckle dragger if I saw that.


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## ponyboy

BBQ said:


> Sorry you are so unskilled, I learned how to make clean holes in block with a hammer my first weeks in the trade.


im happy for you and all others who can smack a wall with a hammer and make a clean hole. i now know why ive been feeling so unfulfilled lately. i'll start practicing immediately so i can be the same caliber craftsman as all the other hammer swingers.


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## BBQ

ponyboy said:


> im happy for you and all others who can smack a wall with a hammer and make a clean hole. i now know why ive been feeling so unfulfilled lately. i'll start practicing immediately so i can be the same caliber craftsman as all the other hammer swingers.


That's the spirit, with some practice you will be fit to tie our shoes. 








:laughing:


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## nolabama

BBQ said:


> That's the spirit, with some practice you will be fit to tie our shoes.
> 
> :laughing:


Quit playing. You wear velcro shoes.... Lol.


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## Southeast Power

ponyboy said:


> im happy for you and all others who can smack a wall with a hammer and make a clean hole. i now know why ive been feeling so unfulfilled lately. i'll start practicing immediately so i can be the same caliber craftsman as all the other hammer swingers.


Make a very deliberate hit and don't let the hammer bounce. Hit and keep the hammerhead against the wall for a second and listen to what is going on inside.
If you have a nice long snout hammer you can usually make a perfect hole for a small sized conduit pretty easy.


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## xlink

Take the block out, wet-core both sides from the outside so you don't blow out the exposed surfaces, insert a short piece of pipe and fire-seal it in place, then put the block back and mortar it in place. If it's an insulated wall, repeat the process with the top block so you can pour the insulation back in. Then, and this is the most important part, tell everyone on the internet that they aren't fit to lick your boots unless they do it the same way.

On your way out, make sure you close the door in the block wall. You wouldn't want the doorway to cave in.


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## John Valdes

BBQ said:


> Sorry you are so unskilled, I learned how to make clean holes in block with a hammer my first weeks in the trade.





jrannis said:


> It's very rare to find a building here that is not CBS (CMU) construction.
> I have never heard of the "micro fracture theory" I think your guy has way too much time on his hands or, is parroting some BS he heard in a bar somewhere.





jrannis said:


> Make a very deliberate hit and don't let the hammer bounce. Hit and keep the hammerhead against the wall for a second and listen to what is going on inside.
> If you have a nice long snout hammer you can usually make a perfect hole for a small sized conduit pretty easy.


My house is block and so were all the houses down in south Fl. were I used to work.
Making a hole in a block with a hammer is simple, easy and frankly, the correct way to do it.
You do not need a drill, or that funny looking punch. Seems like a knuckle buster to me. All you need is a ball peen hammer and a plan.
Find your cavity and using the ball end make a small hole. 
Count your blocks and measure for accuracy and do the same on the opposite side.
I though all electricians did it this way? It is how I was taught to do it.


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## ponyboy

John Valdes said:


> My house is block and so were all the houses down in south Fl. were I used to work.
> Making a hole in a block with a hammer is simple, easy and frankly, the correct way to do it.
> You do not need a drill, or that funny looking punch. Seems like a knuckle buster to me. All you need is a ball peen hammer and a plan.
> Find your cavity and using the ball end make a small hole.
> Count your blocks and measure for accuracy and do the same on the opposite side.
> I though all electricians did it this way? It is how I was taught to do it.


Could be a demographic thing because I've never heard of it until now. Almost 99% of the building I work in are precast concrete so using a hammer to do anything like make a hole is an obviously absurd idea. But apparently it's common practice so I apologize for my earlier comments


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## Wirenuting

Bashing a hole with a hammer isn't the proper way to pound a nail. 

Use that funny punch, a star bit, if you don't have access to a better tool. 

The concept of fractures in block go way back. But it's biggest concern had to do with water intrusion in cold climates. 
We all know block wicks up moisture. But a crack allows water to collect, freeze, expand and blow the block out. This happens over time and not in a weekend. 

In the old, slow and powerless tool days, mortar was mixed and used to seal the hole and surrounding area. The work was preformed so that it would last longer then the tradesman who did it. 

Today we just rush to finish, collect the $$ and go home.


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## TOOL_5150

Wirenuting said:


> Bashing a hole with a hammer isn't the proper way to pound a nail.
> 
> Use that funny punch, a star bit, if you don't have access to a better tool.
> 
> The concept of fractures in block go way back. But it's biggest concern had to do with water intrusion in cold climates.
> We all know block wicks up moisture. But a crack allows water to collect, freeze, expand and blow the block out. This happens over time and not in a weekend.
> 
> In the old, slow and powerless tool days, mortar was mixed and used to seal the hole and surrounding area. The work was preformed so that it would last longer then the tradesman who did it.
> 
> Today we just rush to finish, collect the $$ and go home.



Which is a really bad direction for our trade to go, but it has.


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## B4T

TOOL_5150 said:


> Which is a really bad direction for our trade to go, but it has.


You can blame part of that on HD and Lowes making it easy for anyone to play electrician...

EZ Wiring 101 gives great detailed instructions to anyone who can read..

Being an electrician used to mean you are a skilled craftsman.. not anymore..


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## nolabama

I preferred the Black and Decker wiring book. It was mostly pictures. No difficult reading.


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## Jlarson

I've been doing the ball peen thing for a long time. Estwing ball peens rock.


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## HawkShock

Hammer works great for 3/4 runs, almost perfectly. I am always amazed how little effort it takes to make a hole, and how clean they come out. My preferred method.


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## Hippie

nolabama said:


> I preferred the Black and Decker wiring book. It was mostly pictures. No difficult reading.


Haha I saw the black and Decker "advanced wiring" book at lowes the other day


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## chewy

Does your block not get filled with concrete?


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## mk2munky

chewy said:


> Does your block not get filled with concrete?


Most of the buildings I've worked on, the masons fill maybe every 2 or 3 feet top to bottom, usually denoted by an "X" with wax crayon. Also, most have been steel columns and I-beams with trusses running between. I'd think that would mean the walls were not load bearing.


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## ponyboy

chewy said:


> Does your block not get filled with concrete?


not every course. i think it depends on what purpose the wall serves. like whether its load bearing or not


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## JohnR

I hate when you pop a hole in block, and then find out that you are draining the entire wall of the Styrofoam pellets.


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## denny3992

JohnR said:


> I hate when you pop a hole in block, and then find out that you are draining the entire wall of the Styrofoam pellets.


Or that sandlike insulation! ( perlite?)

Been there done that above a drop ceiling in a bank once!


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## Hippie

denny3992 said:


> Or that sandlike insulation! ( perlite?)
> 
> Been there done that above a drop ceiling in a bank once!


Man I haven't run into that in a long time... Had an avalanche of it spill out a hole all over a desk once when I was an apprentice, I had never seen it and definitely didn't expect it... Thought it was never going to stop coming out


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## gnuuser

yes micro-fracturing is an issue because you dont see the fractures.
this can cause problems in cold and damp climates.
even using a hammer drill can cause micro fractures if you are not careful
wet cutting is the proper method. but if you cannot remove the block then you need hole saw designed for concrete.


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## xlink

gnuuser said:


> wet cutting is the proper method. but if you cannot remove the block then you need hole saw designed for concrete.


The important part is to say "if you don't do it this way, you shouldn't be an electrician". But that was pretty good. :thumbsup:


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## BBQ

gnuuser said:


> yes micro-fracturing is an issue because you dont see the fractures.
> this can cause problems in cold and damp climates.
> even using a hammer drill can cause micro fractures if you are not careful
> wet cutting is the proper method. but if you cannot remove the block then you need hole saw designed for concrete.


Interesting.

Apprently this microfractioning is only an issue for electricians seeing as masons use a masons hammer to shape and make holes in blocks.


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## Southeast Power

gnuuser said:


> yes micro-fracturing is an issue because you dont see the fractures.
> this can cause problems in cold and damp climates.
> even using a hammer drill can cause micro fractures if you are not careful
> wet cutting is the proper method. but if you cannot remove the block then you need hole saw designed for concrete.



Thanks but here, we are more concerned about termites and our 150 mph wind load requirements. I'm sure 3/4" plywood, properly installed would pass wind load but it would just turn into a bug nest.

Simple 2x4 cannon test for windows and doors here,

Get through this wall of reported text:

Impact Window and Door Requirements
Every impact-resistant window and door model offered by CGI goes through the rigorous testing requirements set by Miami-Dade County, the toughest wind-borne debris standard in the world. Our hurricane-safe products are tested and comply with the tougher Large Missile standard.

Of the six testing criteria, there are two key elements to the wind-borne debris testing protocol:

1. The Missile Test (impact requirements)
• Large Missile (structures up to 30 feet)
• 2x4 missile weighing 9 pounds shot from a canon at 50 feet per second – two impacts
• Small Missile (structure from 30 feet and above)
• Ten 2 gram steel balls cannon test at 89 mph – three impacts
2. The Cyclical Test (pressure requirements)
• 4,500 positive cycles in a pressure chamber
• 4,500 negative cycles in a pressure chamber

Note: The Cyclical Test pressure varies between products. The stronger products are tested and pass higher pressure, which equates to higher wind resistance. The resulting test results are documented in terms of pounds per square foot (PSF).
Impact Code Approved 
An impact resistant window or door is only considered ‘impact code approved’ if it has gone through the test requirements defined by an approved code body and received a Notice of Acceptance (NOA) or approval documentation. The pressure of the Cyclical Test used is documented in the approval, shown as PSF (pounds per square foot). All NOA’s are public information and should be accessible through the various code bodies. For Miami-Dade, you can go to their website at: www.miamidade.gov/buildingcode. 

CGI Approvals 
For a complete list of CGI impact code approved windows and doors, you can also visit the Miami-Dade building code website at: http://www.miamidade.gov/building/pc-search_app.asp and the Florida Building Code (FBC) at: http://www.floridabuilding.org/pr/pr_app_srch.aspx


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## Wirenuting

BBQ said:


> Interesting.
> 
> Apprently this microfractioning is only an issue for electricians seeing as masons use a masons hammer to shape and make holes in blocks.


Them hammers have special magical powers when used by "Masons". 
Besides, they mortar around the broken edges.


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## bero35

l was a mason before I was an elecrtrician, and can say that it can damage the block or break the bond. If you have a hollow core and no core bit, you could use a small masonry bit in a drill and make a series of holes in a circular pattern, then knock that out with a hammer and chisel


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## tkb

I guess there are hundreds of buildings that I have worked in that are on the verge of collapse from hammering holes in the concrete block.

What a crock! :laughing:


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## ponyboy

I understand its a common method but using a hammer to make holes is hack.


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## Introyble

Just think of the amazing things Andy did with his rock hammer. Source: The Shawshank Redemption.


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## 360max

Spunk#7 said:


> How about a Dry Core bit on a 7" grinder,works great for me!


Wow, 47 comments on how to make a hole in a block wall. What if the block wall was concrete filled?


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## xlink

360max said:


> Wow, 47 comments on how to make a hole in a block wall. What if the block wall was concrete filled?


Yeah! And what if it was filled with martians?

49 comments, now.


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## Celtic

bero35 said:


> l was a mason before I was an elecrtrician, and can say that it can damage the block or break the bond. If you have a hollow core and no core bit, you could use a small masonry bit in a drill and make a series of holes in a circular pattern, then knock that out with a hammer and chisel


I was a brain surgeon before I was an electrician.
Obviously, I wasn't a very good surgeon as I am an electrician now.
I may have done some work on your medulla oblongata. :thumbsup:


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## erics37

I would never bludgeon my way through a block wall with a hammer.

Hammers are better adapted to bashing big ol' holes through TGI joists.


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## xlink

erics37 said:


> I would never bludgeon my way through a block wall with a hammer.
> 
> Hammers are better adapted to bashing big ol' holes through TGI joists.


When you put it like that it sounds worse than it might be.

Hammer drill a one inch hole right through a block. When you look at the other side, it is blown out. You really need to drill from both sides to hide the damage. The unanswered questions are, which method creates the most damage and is the damage (with either method) acceptable.

Electricians resist new ideas and original-thinking. It's probably the reason we couldn't be trained to be engineers.


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## Wpgshocker

xlink said:


> When you put it like that it sounds worse than it might be.
> 
> Hammer drill a one inch hole right through a block. When you look at the other side, it is blown out. You really need to drill from both sides to hide the damage. The unanswered questions are, which method creates the most damage and is the damage (with either method) acceptable.
> 
> Electricians resist new ideas and original-thinking. It's probably the reason we couldn't be trained to be engineers.


Drilling slowly and letting the tool do the work doesn't cause massive blow outs. The guys that force and lean on their tools cause the blow outs. I have never had a bad brick blow out unless I am in too much of a hurry.


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## gold

I call BS. There's no way a star bit is going to put any more stress on a block then a hammer drill.


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## xlink

Wpgshocker said:


> Drilling slowly and letting the tool do the work doesn't cause massive blow outs. The guys that force and lean on their tools cause the blow outs. I have never had a bad brick blow out unless I am in too much of a hurry.


So, your blocks blow out too. It's a good thing no one checks the inside of the block to see how hard you push when you start the hole. :thumbsup:


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## Wpgshocker

xlink said:


> So, your blocks blow out too. It's a good thing no one checks the inside of the block to see how hard you push when you start the hole. :thumbsup:


Hahaha

Everyone should just use one of these......

http://youtu.be/4H32xnUzZLY


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## Fredman

Wpgshocker said:


> Hahaha
> 
> Everyone should just use one of these......
> 
> http://youtu.be/4H32xnUzZLY



But you still have to drill in the mounting stud to hang the machine.

More Microfractures!!! :whistling2::laughing:


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## xlink

Wpgshocker said:


> Hahaha
> 
> Everyone should just use one of these......
> 
> http://youtu.be/4H32xnUzZLY


If that were a real demo, when he pulled the core out of the saw, there would be a conduit running through the middle of it.


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