Recommendations for cutting through basement wall for chimney

Go to the tool rental shops. We "core drill" sewer manholes to add new pipes. The manholes are concrete and several inches thick. A rotohammer can bore smaller holes much like a drill bit. I've seen a circle of rotohammered holes used to make a big hole. The 12" thickness is the hard part.

You don't say where you are, but you should be able to find a local company or concrete contractor that can cut the hole for you better and probably about as cheap as you renting the tools. Here is a link to one in Mass.

http://www.affordableconcretecutting.com/

I got a quote for adding an egress window to the basement of my last house (a lot bigger than 8" diameter) and it really wasn't all that expensive. They usually use water to cool the bit/blade and that keeps the dust down.

I dont think this is something you want to try to do yourself, there may even be rebar in there. See if you can find a concrete sawing co. With there equipment they can core that hole in about an hour including setup.

I don't know about where you are but out here I can rent a core drill for 100+ or I can have a core drilling company do it for 150.00. It's a real easy choice if you've ever gone through the misery of core drilling a foundation with a machine you're not familiar with.

I have done this exact job two times before. What I used is that little "air chisel" that is powered by an air compressor. You know, the little hand held air chisel gun that will act like a mini jack hammer.

What I did was to first draw the circle with a marker on the concrete wall, then I drilled small pilot holes all around the circle with a 1/4 '' masonry bit to "score" the round circle in the masonry wall all the way through it. This way, when you go to "jackhammer" it with the air chisel, the concrete chunks will break off at the drill hole marks, creating a nice, semi-clean cut.

It is very time consuming to do this, but is cost me nothing to do. I would say it took about 45 min to drill all the pilot holes, and another hour to chisel all the way through, (approching it from both sides..All in in, you could do the job in a few hours for free. You just have to decide if its worth doing it yourself or not.

can I shead a little light to this situation First of all no one mentioned PE #1 eye protection #2 ear protection #3 breathing protection who wants to breath all the fine concrete dust or visit the ER to remove a comcrete chip from your eye.

I have to differ my opinion from super hunky: Ever drill 3000 psi concrete with granite agregate? Have you seen what one 1" granite stone will do to a concrete bit?

12" 8" hole is qi uite an undertaking which can not be accomplished in the time SH said with common home owner tools I have an hatachi comercial hammer drill that is capable of drilling a 12" with 2.5" bits and also chisel like a real chipping hammer If you have 12 ' concrete block that is hollow that is doable by home owners but this is a very heavy undertaking Very exxhausting holding a 55 lb hammet drill in position to work. You will get a workout never experienced in a gym and vibrations that will numb your hands up to your shoulders to boot qi uite a mess to clean up and duts can travel a long distance. if you think you need an 8" hole then cut 10". It can be done but it is quite abit more demanding than 45 minutes. Without the right tools don't even try to attempt it you are wasting your time. and going to the rental place is the first stop. After thinking it over subcontracting someone else or core drilling might be the best route

Hammer Drill

Elk,

You forgot to tell him to pull a permit

My first thought is can you reroute the chimney and not have it go outside so soon? You could avoid the drilling through concrete and probably have a better draft if the chimney is inside longer. Go up over the foundation and then out, could you do that? We have concrete block walls in our basement, but the 'house' part starts on top of that with the wooden box sills and so on. Could you just exit a little higher up and avoid the problem? When we had our gas furnace put in 4 years ago (replacing an oil furnace) it was SO cold that their drills weren't working well. So instead of running the air in and out pipes through the concrete blocks as they had intended, they ran them a bit higher and went out through the wall of the house and the siding. A chimney is a bit larger but maybe you could manage it somehow? Just a thought.

karl said:

Elk,

You forgot to tell him to pull a permit

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No permit needed to cut the hole but required to construct the chimney and install the stove

i definitely side with elk. i have to cut holes in concrete for electrical piping and i can say the same. the time it takes and work and abuse to the body from vibration and fatigue it's well worth calling a concrete cutting contractor. he will probably be done in just a few hours with his coring drill which is better than the ones you rent.

We cut through our basement's 12" block using a DeWalt wired hammer drill and the longest 3/8" Bosch drill they had at the Depot. First we drew a circle with a pencil and hubby drilled every inch or so to the outside. The trick is to keep the drill straight and level. Then we banged it all out with a cold chisel and hand held sledge. After running the pipe through and using small pieces of the broken concrete to level the pipe, I sealed around it with quick setting cement that you can buy and mix in the same bucket. All was done in about an hour.

Elk:

My method mentioned above is very effective and like I said, it will take a few hours to do. I did not mention that I ended up using a Bosch hammer drill to drill the pilot holes. I first used a Milwaukee holeshooter 1/2'' drill with a long masonry bit and while it DID work, (remember, this is not a "hypothetical" scenario, I actually did it), the regular drill took forever just to drill one hole.

The Bosch hammer drill (borrowed from a friend), drilled each hole VERY VERY quickly.

Elk makes many good points concerning safety. The air chisel will chip out concrete dust and bits everywhere. I did not use eye protection, dust mask, or ear protection which was a mistake. My eyes were pink at the end of the day from irratating concrete dust, my teeth were gritty, and even my nose had dust in it.

The ear protection is also a good idea, however, not due to the noise (as it is not really loud), but due to tiny concrete chips getting tossed into your ears.

I've finally figured out how to wipe my eyes and blow my nose, but I still have'nt figured out a good way to dislodge concrete chips/dust from my ears other than wacking the side of my head while tilted!.

Kind of makes you reconsider the use of the term, "I did it for free"!!

SH it was not personal intended in any way but more of a message that this is rugged work and PE required

Mr_Super-Hunky said:

Elk:

My method mentioned above is very effective and like I said, it will take a few hours to do. I did not mention that I ended up using a Bosch hammer drill to drill the pilot holes. I first used a Milwaukee holeshooter 1/2'' drill with a long masonry bit and while it DID work, (remember, this is not a "hypothetical" scenario, I actually did it), the regular drill took forever just to drill one hole.

The Bosch hammer drill (borrowed from a friend), drilled each hole VERY VERY quickly.

Elk makes many good points concerning safety. The air chisel will chip out concrete dust and bits everywhere. I did not use eye protection, dust mask, or ear protection which was a mistake. My eyes were pink at the end of the day from irratating concrete dust, my teeth were gritty, and even my nose had dust in it.

The ear protection is also a good idea, however, not due to the noise (as it is not really loud), but due to tiny concrete chips getting tossed into your ears.

I've finally figured out how to wipe my eyes and blow my nose, but I still have'nt figured out a good way to dislodge concrete chips/dust from my ears other than wacking the side of my head while tilted!.

Kind of makes you reconsider the use of the term, "I did it for free"!!

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Just "for fun" call someone that does 'coring' and request a quote... never know, all that work you did, you might end up saying "I did all that work just to save how much???"

Perhaps you or I can laugh off "Getting smacked upside the head with a Hilti"...but the average weekend warrior might not. Some of you out there know what I'm talking about...while it has never happened to me 'personally' (in case you were wondering)...I know plenty of guys it has happened to...When you see a guy like MrSuperHunky get smacked off the jaw by a TE92 that gets hung up...and knocked to the ground in agony???

...Glad to hear you got it done...but word to the wise, somethings sometimes "Doesn't pay to do yourself". To those who might be watching with some interest (i.e. "in the future" ) call for a quote..."it's what they are there for."

WORD TO THE WISE...This is an example of "when things went right"...you gotta ask the ER folks about the other side of the coin... Just play it safe and know what you are in for...

..Thats all I'm trying to say folks.

As to the original post...Not all hammer drills are the same. Makita, Bosch, Hilti etc. etc. If you do decide to brrow or rent a hammer drill be sure you are familiar with what you are using. Personally, My own recomendation would be go to a rental place and ask if they have either a Hilti (fairly 'smoke proof')TE52 or TE72 with the 'clutch setting'. If you feel really bold...get the TE92 'widow maker' and have a ball...just make sure you are ready to "hold onto a ride" if necessary...

You haven't lived life until you have to 'blast' through N-A_T-O hardened concrete (nuke blast resistant) to make a three foot around hole...with 'bar' 4" O.C. pattern wielding a TE92...

Yeah..I have, I took over for the kid that went "off to the ER".

"Been there...wrecked that" and 'smoked' a few hammerdrills...lol

12" thick concrete foundation wall?? Sounds a little 'un-orthodox'... Sure it isn't ten inches???

Here's a picture of the 6" (8" O.D.) pipe going through the 12" cinder block wall.

Highbeam said:

Go to the tool rental shops. We "core drill" sewer manholes to add new pipes. The manholes are concrete and several inches thick. A rotohammer can bore smaller holes much like a drill bit. I've seen a circle of rotohammered holes used to make a big hole. The 12" thickness is the hard part.

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"Punch a few structures" I take it highbeam??

Bet you have a few good "war stories" then... lol

if i can make one more point. just remember for those people out there that are thinking about doing there own, a 12 inch poured concrete foundation is a lot harder to go thru and chisel than block foundation. even if you use a hammer drill or rotary hammer it's still a lot harder to chisel out.

It really depends on the concrete. Comparing a concrete wall to a block wall isn't really an even comparison. Block can be chopped through with a sledge hammer. The bottom line is that you can definitely do it but if you run into a lot of rebar it will ruin your day.

Some Like It Hot said:

My first thought is can you reroute the chimney and not have it go outside so soon? You could avoid the drilling through concrete and probably have a better draft if the chimney is inside longer. Go up over the foundation and then out, could you do that? We have concrete block walls in our basement, but the 'house' part starts on top of that with the wooden box sills and so on. Could you just exit a little higher up and avoid the problem? When we had our gas furnace put in 4 years ago (replacing an oil furnace) it was SO cold that their drills weren't working well. So instead of running the air in and out pipes through the concrete blocks as they had intended, they ran them a bit higher and went out through the wall of the house and the siding. A chimney is a bit larger but maybe you could manage it somehow? Just a thought.

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While I would second the notion of "going up inside" and avoiding the evil outside chimney, I think your notion has a few problems... The thought isn't bad, but this is a case where it won't really work.

1. Biggest single issue - the plastic 4" I/O pipes on a high efficiency gas furnace basically have no clearance requirements on the holes - just drill a hole in a joist or wall plate and stuff the pipe through. To get a stove chimney through a wall requires a MUCH larger hole for both the pipe and the required clearance to combustibles. I don't think you'd have room in most homes to go out through the sills. As long as they are far enough from combustibles, the idea of going through the concrete will require less clearance and probably be easier to build.

2. Going up to the sill space would probably also involve even more issues with clearances to combustibles with the pipe elbow and the horizontal run because they'd be to close to the underside of the combustible floor above.

3. While going all the way up to the roof on the inside would likely result in a much better drafting install (but would probably cause issues with the pipe going through the upper floor living spaces, along with the required enclosures)
I doubt that keeping the pipe inside for just a couple of extra feet would make a noticeable difference.

Gooserider

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