What is best way to cut a hole in brick chimney? (Masonary grinding wheel, Air chisel... ? Other ide

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Northeaster1

New Member
Oct 10, 2008
119
Nova Scotia
I have to cut out a new hole, for the tee of a new ss liner, as the old opening is not in the room, where the stove will be located. Will brick in the old hole.

Tried Bosch masonary bit, but seemed to dull after only a couple of holes. In hindsite, should have only drilled in mortar lines, instead of trying to drill through red brick, to make nice, round hole.

Then tried masonary cut-off wheels in 4 1/2" grinder. Better, but snapped a couple of wheels off. May get thicker wheels, instead of very thin cut-off wheels, which are not forgiving, if you do not stay very straight.

Do people use air chisels?
Would an air chisel do much damage to surrounding bricks, like loosening them all?

Any help would be appreciated!
 
Best (not cheapest)way is a masonry core bit that can be rented at the big box stores. They don't usually have a center pilot point, but the make for a real nice core. It would be on the big side if you are putting a pipe through the hole, you would need a big drill to get it through. If you are using masonry bits around the perimeter of the hole to be cut, use a hammer drill not a regular drill. Hammer drill with masonry bit will go through brick real nice. Use cold chisel after that to work at the brick between the holes.
 
If you're putting in a tee a round hole isn't going to do you much good, but I can understand if this is going to show that it may be worth the trouble. If you've got a second set of hands and get lucky you can glide the tee down through the chimney and land it in the right spot, then reach inside and tighten the thimble. I didn't have brick to do mine, just cement block. I've got a Hilti TE55. YEEEEEEEEHAAAAAAAAAA!. Nice big hole in about 2 minutes. Brick it up and cement it in place. Wasn't going to show but if its an exposed spot in the living room you're going to want a more finished look.

I'm guessing you're using a regular type of masonary drill bit. A rotary hammer drill is what you want, it will go through the brick like butter. The first time I used one I almost cried "ALL THE WASTED YEARS!!!" You can get a 3/8" bit about 12-18" long (depending on the thickness of your chimney) and drill in a tight circle around the new thimble. After installation make/buy a trim plate that will fit around your new pipe.
 
I was using a hammer drill, but only a Dewalt 18V cordless hammer drill - not in the same league as a Hilti!

May have to break down and rent a Hilti.
 
You need to get a diamond wheel for your grinder. Use a shop-vac to collect the dust as you cut your hole, then finish it with a cold chisel, air chisel or rotary hammer.
 
Not all bricks are soft. I have found bricks that resisted a large Kango for quite a while. I small hammerdrill, even a small hilti would have done nothing. A core drill is the ultimate tool for this job. They will drill through pink granite and give a perfectly sized, perfectly round hole, without loosening any brick, mortor or flue tile. Core drills are an impact free tool and cut by grinding with industrial diamond. Trades who may own core drills include plumbers, electricians, ironworkers and builders. I often core holes for other trades.

All the methods above will also work.
 
OK, what size hole are we talking about? When I did core drilling I got paid by the inch, and the price went up as the hole diameter increased. You can rent the drill/bit but an inexperienced operator can smoke a $500 bit pretty quick. You're not drilling reinforced concrete, and unless you get very unlucky you're not going to hit steel. If its an old chimney it may be a good idea because I've blown out walls in weaker walls. You walk around that corner to see what the big noise was and just about wet your pants! But I digress.

I like the grinder-then-drill idea. That will give you a very clean hole.
 
rent a hammer drill. Outine the area you want to punch out w/ a sharpie... then turn that space into swiss cheese with a rotary bit. Afterwards, chisel it all out, either by hand, or with the chipper function and chisel bit on the hammer drill.
 
Hey there Nova Scotia...I did the same project that you are doing, except the brick chimney is visible in my second floor now, where it was buried behind a wall before. I used a hammer drill, masonry bit and a 4-1/2 grinder with a diamond blade to cut a fairly neat hole. Made quite a mess with the dust flying all around, sealed of doorways with plastic and taped gaps. One masonry bit took me through the entire project.
Just out of curiosity, what kind of wood do you folks burn in the eastern maritimes?
 
btuser said:
OK, what size hole are we talking about? When I did core drilling I got paid by the inch, and the price went up as the hole diameter increased. You can rent the drill/bit but an inexperienced operator can smoke a $500 bit pretty quick. You're not drilling reinforced concrete, and unless you get very unlucky you're not going to hit steel. If its an old chimney it may be a good idea because I've blown out walls in weaker walls. You walk around that corner to see what the big noise was and just about wet your pants! But I digress.

I like the grinder-then-drill idea. That will give you a very clean hole.

I charged $200 for up to three holes, usualy 2" and 6" for the plumber and four inch for the electrician, or $100 for one hole. I also drill a few holes as favors. My most expensive bit cost $200. These days I will drill a hole for $50 bucks. A lot of people are looking for work. I would rather give a tradesman $50 than a bigbox store.

As I said above, all the other methods work, but coring is the best.
 
In my home, the builder never installed any sort of cleanout in the exterior masonry chimney, so I had to retrofit one. I used a hammer drill to outline a square hole for a cleanout door. Made holes about an inch apart. It was then easy to chisel out the brick. What surprised me was how tough the clay liner was to chisel. At first I was tapping lightly, afraid to crack the liner. I gradually hammered on the chisel harder and harder, and eventually found that it was all I could do to swing the hammer hard enough to chip the liner at all. Finally managed to chisel out the square hole in the liner as well, and then it was ready for a cleanout door.
 
When we installed my stove, we drilled a 3/8" hole about every inch around the perimeter of the hole to be made. Then took a large masonry chisel and hammer and hammered around the edges until the brick just crumbled away. It was pretty easy but we had a good size hammer drill.
 
I did what mrfjsf described, using a Ryobi hammer drill and Bosch bits. Here are pics, from start to thimble in.

If it's a chimney, you might consider putting a service entrance on the other side.
 

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You might call a few concrete cutting companies and see what they would charge, you might be surprised. If not you can rent an SDS hammer drill and rent a core bit along with it. The other option is to make a series of 1/4-1/2" holes about 1" apart then put a chisle bit in the SDS and break it all out. Be careful though since old brick/block tends to blow out on the other side. Hammer drilling will not make nice clean holes only a core bit will do that for you.
 
precaud said:
I did what mrfjsf described, using a Ryobi hammer drill and Bosch bits. Here are pics, from start to thimble in.

If it's a chimney, you might consider putting a service entrance on the other side.

This is basically an exact replica of my install. If you have a big enought hammer drill, you will be fine. It took about 2 hrs to do, and that is only because we had a few clearance issues. Otherwise it would have took under an hour.
 
mrfjsf said:
When we installed my stove, we drilled a 3/8" hole about every inch around the perimeter of the hole to be made. Then took a large masonry chisel and hammer and hammered around the edges until the brick just crumbled away. It was pretty easy but we had a good size hammer drill.
.

This gets my vote, but I'd use a good grinder wheel to score the bricks as well.

If you get stuck, PM me and I could come take a look - I'm just down the road in Kentville.
 
Well, the hole is now done. Made good progress with a bit thicker masonary ginding wheel, until my dewalt grinder died. I don't think it liked turning a 7" wheel, since it is only a 4 1/2" grinder.
It had lots of hours on it from welding up a couple of trailers, but woulod have likely lasted had I not abused it..

Continued progress with cold chisel, and then a sledge hammer, once I had a decent slot exposed. Went quite easily one I had one bric koutm, then another.. as thye were then not supported on all sides.

Thanks for all of the advice! Will be installing the liner (insulated) on the weekend, if the weather cooperates. Still have roof jacks on the roof, as we just rehingled the 13/12 pitch roof last weekend.
That should make it easier to work up there.
 
Glad you got it licked. Brick and masonry is stubborn stuff.
 
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