# Must Make ~2.5" Hole In Poured Concrete Foundation Wall



## velvetfoot (Apr 21, 2014)

I'm relocating my fuel oil tank and need to drill through the foundation wall.  I've been looking at the rental places.  I've seen a handheld watercooled diamond core drill.  Also a handheld dry rotary hammer carbide core drill.  The one place also had a mounted watercooled diamond core drill, but I didn't see it.  A big concern is what to do if I hit a piece of rebar. Would a watercooled diamond core drill go through the rebar?  I'm thinking perhaps a carbide tipped hole saw or maybe a sawzall.  The hammer drill was quite heavy but had a pilot drill.  I don't know how level and square a handheld drill can do.  I'm thinking tomorrow I will take a closer look at what is called "freestand core drill" in their price sheet.

Any suggestions?


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## waynewagner33 (Apr 21, 2014)

diamond core drill goes through rebar no issue drycore bits rebar is an issue over one foot of concrete I would suggest the one u can mount


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## velvetfoot (Apr 21, 2014)

Thanks. So possible to go through ~8" of concrete with a handheld wet diamond core drill?  
I searched on "freestand core drills"..might be a fair amount of effort to lift and mount it.


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## waynewagner33 (Apr 21, 2014)

Yea not so easy to get started but definitely doable


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## velvetfoot (Apr 21, 2014)

OK, thanks.


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## cityboy172 (Apr 21, 2014)

velvetfoot said:


> Thanks. So possible to go through ~8" of concrete with a handheld wet diamond core drill?
> I searched on "freestand core drills"..might be a fair amount of effort to lift and mount it.


 

Free handing a wall  is not for beginners. A floor, maybe. As far as thickness, I've done 20" +   with extensions.  It gets a little tricky after you bottom the bit out.

 Do a wet core with a stand.  The rotary hammer drill won't go through bar. A dry core will struggle through bar alot, and might make it through. A wet core will go through bar just fine.  It will slow down a little while going through the bar, but usually won't cause a problem (unless you cut a sliver of bar). Keep in mind that all failed attempts will forever be in your wall, so do it right the first time.


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## velvetfoot (Apr 21, 2014)

cityboy172 said:


> Keep in mind that all failed attempts will forever be in your wall, so do it right the first time.


Yep, and the first time will be MY first time.


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## cityboy172 (Apr 21, 2014)

If your dead set on free handing here are some pointers to help.

To help get perfect starts every time, we  made templates. Take a piece of plywood and drill a 2.5" hole in it.  On a floor hole we would stand on it. On a wall hole, You could run 2 plastic anchors in it to hold it, or have a some one hold it (not reccomended for beginners). If your going to drill anchors, you might as well wall mount it though. 

Once you have your ring "scored" in the wall, lay the water to it heavy. It will fling every where.  Vis queen the area off and have a shop vac ready or running the whole time. have your buddy who held the template run the shop vac to clean the water and "mud" up. Not enough water will mess your day all up.  The water serves 2 purposes. to cool the "teeth" and to remove the concrete that has been cut.  It comes out as "mud".  If there is not enough water to remove the mud, it will be dust, and it will bind the bit.

Have your friend that is running  the shop vac make sure that your bit stays level the whole time, both ways. Every time you move, you shift the path of the bit. every time you shift the path of the bit, the slug ( the inner part of what your cutting out) and the hole will grab the bit tighter and tighter.   Do it enough times, and it will bind the bit.

I'm sure there's more, just can't think right now.  The main thing is that there is a lot of things going on all at once, and if you are not aware they can cause problems.


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## velvetfoot (Apr 21, 2014)

Thanks for the tips.  I'm not dead set on anything, for sure.


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## peakbagger (Apr 22, 2014)

.I have just drilled a series of 1/2" holes with carbide bit and a a hammer drill and used a chisel to break  out the resultant plug. The resulting hole is obviously quite rough but if you need to clean it up,just drill it oversize, slide a sleeve in and just grout in the sleeve. I have a friend that cut a 3'by 8' hole in his basement wall using that method. It took him awhile. The biggest hassle was breaking the resulting plug up and hauling the pieces out of the basement.

One of the more impressive holes I did when I was working for an old papermill was a 30" horizontal hole through an old tank foundation that was 8' thick. When it was poured in the 1920's concrete was expensive so they threw granite blocks in with the pour.


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## ironpony (Apr 22, 2014)

all good advice, 2.5 inch should be fairly easy to control. we core 4.5 by hand all the time for radon systems. how big is the line?? maybe just a 1 inch concrete bit?? oil lines are usually small diameter 1/2 inch or less??? or is this the fill line?? might want to go oversize 3 inch so you have some room in case you are out of level. instead of going thru the foundation maybe you can go thru the band board(wood) instead??


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## velvetfoot (Apr 22, 2014)

ironpony said:


> might want to go oversize 3 inch so you have some room in case you are out of level.


You know, I was just thinking the same thing. 



ironpony said:


> we core 4.5 by hand all the time for radon systems


Water or dry, and through a wall?  I'm looking at some YouTube videos and it seems like dry diamond core bits are available, not just the dry carbide core bits they have at HD.


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## velvetfoot (Apr 22, 2014)

ironpony said:


> instead of going thru the foundation maybe you can go thru the band board(wood) instead??


The ground is sloping.  The oil man, who hopefully would not be making too many visits, would have to stand on steps to reach the filler.


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## velvetfoot (Apr 22, 2014)

Stopped by the hardware/rental store today.  The equipment there looks crude compared to the stuff I've seen on the web.  Unless I find another rental place, I'll probably go with the hand held.  The rig version there was extremely heavy and requires fours lag bolts.


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## begreen (Apr 22, 2014)

ironpony said:


> all good advice, 2.5 inch should be fairly easy to control. we core 4.5 by hand all the time for radon systems. how big is the line?? maybe just a 1 inch concrete bit?? oil lines are usually small diameter 1/2 inch or less??? or is this the fill line?? might want to go oversize 3 inch so you have some room in case you are out of level. instead of going thru the foundation maybe you can go thru the band board(wood) instead??



Yes, usually these are 3/8" supply and return lines. If so I would think that a couple 5/8" holes would suffice.


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## velvetfoot (Apr 22, 2014)

begreen said:


> Yes, usually these are 3/8" supply and return lines. If so I would think that a couple 5/8" holes would suffice


They are fill and vent line-2" metal pipe.


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## ironpony (Apr 22, 2014)

we use both wet and dry bits, wet definitely work better. yes thru walls.


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## velvetfoot (Apr 22, 2014)

Thanks.  My latest experience with the diamond wet saw on granite tiles was great, so wet diamond it is.


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## begreen (Apr 22, 2014)

velvetfoot said:


> They are fill and vent line-2" metal pipe.



Ah, I was thinking outdoor tank. Happy nibbling, sounds like you are getting some good advice.


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## velvetfoot (Apr 22, 2014)

Yep.


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## ironpony (Apr 22, 2014)

just had a thought, you said "foundation", so I went back and re read it you did not say if it is  block or poured??? block would be a piece of cake very "soft". poured will be tougher but very do able.


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## velvetfoot (Apr 22, 2014)

Sure, now you tell me.    The post title is:  Must Make ~2.5" Hole In Poured Concrete Foundation Wall

I'm going to look around a little more.


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## velvetfoot (Apr 23, 2014)

I found this Husky at another place.  It's way lighter.  They only have a 2.5" bit though.  The OD of the 2" pipe is supposedly 2.375" (have to measure).


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## velvetfoot (Apr 23, 2014)

The other branch of this place has the Husky with a 3" core bit.  That's the way I'll go.


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## loadstarken (Apr 29, 2014)

When I rerouted my water main I rented a Hilti hammer drill and a 4 inch core bit from Home Depot and it went thru my foundation like a hot knife thru butter.   The rental guy said not to use water because it would just slow the tool down.   I did what he said because I wasn't going to buy a broken tool if I got it wet. 

I picked the tool up an hour before they closed and drove home 15 minutes then drilled the hole and drove back 15 minutes to Home Depot and still had time to buy a 4 inch PVC pipe.


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## velvetfoot (Apr 29, 2014)

I figured with my luck I'd hit a piece of metal which would stop a carbide core drill driven by a hammer drill.


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## loadstarken (Apr 29, 2014)

There was a bit of bar in the hole that I drilled and I didn't even feel it.  

What would it cost to have a cement cutting/drilling company come out and drill a hole?   I didn't look into it when I did mine because it was late on a weekend and had to get done ASAP.


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## velvetfoot (Apr 29, 2014)

I'm assuming your bit was carbide, right?  I've read about drilling dry with diamond core bits, but I don't think they're used with a hammer drill.
I didn't find a dry diamond core drill rental around here-they want you to use water.

I couldn't even find a guy to get a quote.  I'm sure they're out there-somewhere.


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## loadstarken (May 2, 2014)

I believe it was a carbide bit but I could be wrong.


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## joes169 (May 2, 2014)

We have a few carbide core bits that we use occasionally, 3" , 4.25", and 5".  They are all spline drive and run in a 1.5" roto-hammer.  This is certainly the harder way to drill large holes, when compared to a core rig, but it will get the job done for alot less money.  I would recommend you rent something similar with a 3" core bit, and just mortar the pipe in at teh end.  It should be fairly cheap to rent, and easy to find........


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## velvetfoot (Jul 1, 2014)

To close the loop, I drilled a couple of 4" holes today.  It went very smoothly.  I describe it and enclose pictures here:
My Windhager BioWin 100/150 Install Thread


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