# Drilling concrete block for conduit - cable pass-through



## FlyFisher (Jun 30, 2018)

I am looking at putting a standard 1" iron pipe through a concrete block wall for a cable pass-through. The pipe is 1" ID and 1.320" OD. 

Does anyone know if a 1-1/4" bit for a rotary hammer will work - maybe with wollering out the hole a bit to get the pipe through? Or will the hole left by a 1-1/4" bit have enough clearance to pass the pipe? 

Are there any tricks to getting through the block without shattering it? 

My plan is to weld a flange on the outside end of the pipe and secure that to the wall with smaller bolts. This way I can put caps on the pipe when not in use and tighten them with a wrench without the pipe through the block spinning in the block.


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## iowagold (Jan 22, 2020)

just use a core drill.
you can rent those.


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## iowagold (Jan 22, 2020)

make sure to use water with the diamond core drill.
most home centers as well as rental places rent them.
they are heavy so build a support or eyes and come a long for the support 
or use chain and turn buckles depending on the cord drill.

if done right they make perfect holes in a solid wall or block.


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## tabora (Sep 6, 2018)

FlyFisher said:


> Are there any tricks to getting through the block without shattering it?





iowagold said:


> just use a core drill.


I had to put a 6" drain pipe through two 10" solid concrete walls. I rented a core drill from the local rental outfit and it sure did the job. Drilled 2-3" at a time and then used a baby sledge and chisel to break off the core. It would go through concrete block like a hot knife through butter.


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## iowagold (Jan 22, 2020)

yup a core drill is the tool for sure!
most of the time we over drill then line the hole with dwv and seal the dwv in place.
you can use it as a feed through for future pipes or wires as well.
leave a bit of pipe maybe 3-4 inches out on the ends and notch the push on caps and use plumbers putty to fill the small gaps.
it makes for an good looking solution!


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## wingless (Oct 29, 2019)

My current remodel project includes making many new or modifying existing holes in my cinder block walls for wiring, plumbing and A/C.

Hammer drilling is great for new holes.

Modification of existing holes works really well using my SDS Max demolition hammer and a long pointed bit.

Here is an example where I added the required ground wire to the existing copper incoming water pipe. I then used Quikrete Fast Set Repair Mortar to patch the hole. I have had excellent results w/ this mortar to fix many holes around the house.


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## FlyFisher (Jun 30, 2018)

wingless said:


> My current remodel project includes making many new or modifying existing holes in my cinder block walls for wiring, plumbing and A/C.
> 
> Hammer drilling is great for new holes.


Excellent post. Thanks! 

I have a hammer drill here, SDS+, for the project. I am going to try a small twist bit first to make a pilot hole then go easy at it to chip it away. I am not too concerned about a "perfect hole", I just don't want to shatter the block all the way across. 

I did get some caulk for concrete brick - it is a type of flexible "mortar" that is squeezed out of a caulk gun tube. I can get the details on it soon, I just forget what it is off the top of my head (was some stuff I picked up at lowes). 

I welded a 3" square plate flange to a 1" ID black iron pipe as my pass-thru pipe. The idea is to drill the hole in the block, pass the pipe through, then bolt the flange to the block with 4 bolts. The pipe will be sealed against the block with the caulk - both around the pipe in the "hole" and underneath the flange plate on the face of the block.


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## wingless (Oct 29, 2019)

YW

Remember the 8x8x16 concrete block is either solid, has a single central web w/ cavities on either side, has a double central (for splitting in half, two 8x8x8 blocks), or has side cavities intentionally filled w/ mortar. I had one FUN project where I had to remove mortar from many hollow blocks for a vertical internal run.

For the hole placement, hope / plan on hollow side cavities w/ ~1" side and central webs to hopefully go through air, after poking holes in the faces.

Still recommend the fast set mortar over caulk. It is EASY to work with, FAST setting and permanent solution.


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## FlyFisher (Jun 30, 2018)

Thanks. 

As to hole placement - I have whole blocks I can pick anywhere on the block to poke thru. The blocks, I believe, measure 7.5" wide (wall thickness). I am assuming the blocks are the style with single web in the middle. I am not sure if they are filled, however. I suppose the might be. If they are that may make them less susceptible to fracturing. I'll find out with my pilot hole.


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## iowagold (Jan 22, 2020)

hummmmm
copper and concrete direct.....
hummmmm
not my choice....
copper reacts with salts and minerals...
i would to have used dwv as a liner then proper sealer for the transition.
that ground wire will be an issue over time....

we have been using pex as liner as well!
or just do it in good pex.

converting the house here over to pex this summer in my spare time.
sure goes in fast!
and doing a recirculate system for pre heat in cold months.
pretty cool stuff!


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## FlyFisher (Jun 30, 2018)

FlyFisher said:


> I did get some caulk for concrete brick - it is a type of flexible "mortar" that is squeezed out of a caulk gun tube. I can get the details on it soon, I just forget what it is off the top of my head (was some stuff I picked up at lowes).


This is the stuff:


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## FlyFisher (Jun 30, 2018)

iowagold said:


> converting the house here over to pex this summer in my spare time.
> sure goes in fast!


We have been using pex at the cabins for years. Our maintenance guys started using it a long time ago for repairs. The running joke up there is everything is done "temporarily permanent". In the winter time things freeze up pretty good and we've had a round of family opening things back up for hunting post-winterization with no re-winterization, thus water in the pipes froze and you can guess what we went back to the next year. Converting from copper to pex is pretty easy with the compression fittings. I installed a new water heater about 4-6 years ago and ran it with pex. The 2 best parts about it - 1. no sweating pipes, 2. flexible.


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## wingless (Oct 29, 2019)

iowagold said:


> hummmmm
> copper and concrete direct.....
> hummmmm
> not my choice....
> ...


 The house was built in 1963 w/ bare copper penetrating the concrete wall and slab at several locations.

During this remodel the copper was inspected and zero degradation was observed at all concrete to copper contact locations. My speculation is that the copper will outlast me.

According to the Copper Development Association Inc. there is not an issue with this installation.




iowagold said:


> we have been using pex as liner as well!
> or just do it in good pex.
> 
> converting the house here over to pex this summer in my spare time.
> sure goes in fast!


 The factory used PEX for the fresh water when they built my boat. During my upgrades, repairs and service I have retained PEX for that installation.

This remodel retained usage of soldered copper for the fresh water system. I am happy w/ the installation.

Galvanic isolation was used at all locations to prevent dissimilar metal contact, such as at all the galvanized steel nail guard plates near the copper pipes.


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## wingless (Oct 29, 2019)

The water heater was changed to tankless, placed in the closet next to the bathroom.

Part of that installation was the shutoff valves w/ the required over temperature / over pressure relief valve.

The plumbing for that relief valve is required to be 3/4" sloping downhill w/o any dips or droops, exiting at the prescribed height above ground, w/ no valves, so probably not appropriate for PEX.

That is shown in my images as the highest pipe, exiting through the side wall.


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## iowagold (Jan 22, 2020)

nice isolate-rs on the studs!
nice touch!
stops the popping sounds of running water expansion!

love the idea of pex as long as it is the good stuff.


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## DominikPratt (2 mo ago)

Working with concrete blocks depends on their type. If it is aerated concrete or foam concrete, this drill will do. To install the pipe you need to use double drills or core drill. When we were installing pipes in the basement we invited Concrete Contractor | Almighty Construction | Washington | Cement company. The specialists suggested using diamond cutting, and to my surprise it was a better solution. We impregnated all the holes with a waterproofing compound so that moisture does not accumulate in the gaps between the blocks of concrete. As far as I remember a hammer drill was used in the work so I think you can do the job.


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