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View Full Version : Pseudo-OT: Cutting a hole in a chimney/flue liner and wood burning stoves



Fasttrack
09-25-2012, 03:28 PM
Well, it's that time of year again. I've been looking at installing a wood stove in my living room. I have a large chimney that runs up through the center of the house from the basement. The chimney has three flues. One for the basement fireplace, one for the furnace and one that is unused and sealed with stone and a mortar cap. My mortar cap is crumbling and needs to be replaced anyway and I've partially uncovered the extra flue. The terracotta flue tiles appear to be in good shape. I would like to tap into this for my stove. The chimney is a masonry chimney made of 16 by 8 by 8 cinder blocks. In the living room, this is covered over with plaster with gypsum lathes.

The question is ... how do I access this flue? My thoughts were to use a hammer drill and a small drill bit and perforate a circle in the cinder block. To locate the flue, I'm assuming it is plumb and I can do some measuring at the top of the chimney and then use the same measurement inside to locate it. Maybe the first circle removed will only be about 3" diameter to make sure I can find the flue tiles. Then expand to a 6" diameter. Hopefully I can cut a neat hole in the cinder block without damaging the tile (Ha! good luck, right?) and then use an abrasive bit of some sort to carefully cut a hole in the flue tile. I could then run some kind of thimble into the flue tile to finish the job.


What do you guys say? For those of you with wood burning stoves in your shop, what brand/models did you buy? Anyone build their own? How'd you handle the chimney?

MrFluffy
09-25-2012, 04:27 PM
I made my own double insulated chimney and stuck it outside :)
I took one of those 150mm stainless flue liners, and rolled fireboard insulation round it, and lockwired it in place, then I got some 250mm stainless thinwall tube sections someone donated me and slid it onto the isolated stainless pipe then tigged all the joints together, and made some iron stand offs and cemented them into the stone wall and then raised it in one length using the backhoe and clamped it in place..
It looks great, works great especially in cold weather the draw is strong(this is for the house, not the shop and we have a 60kw hs tarm wood furnace) and its stood a 120mph wind and three rough winters so far without a issue. I keep saying to my wife if we should spend out on a "proper" one as we only ever intended it as a stop gap for that winter, and she keeps saying why bother.

On our other house it had a clay tile hollow chimney. We just knocked a hole in it with a masons chisel for the tube and fire cemented around the connection after we'd made it...

MrFluffy
09-25-2012, 04:30 PM
Oh and having worked on a few dodgy houses, I *really* wouldnt make the assumption that the flue is going to be plumb to anything. Near enough is good when your crawling round a roof in some rough weather... I'd drop a plumb bob down from the highest point and check it stays central to test that assumption...

For my previous post, I forgot to add the usual disclaimer, dont do this at home, its not to code, your insurance doesnt allow you to make your own chimney, etc etc etc... If I ever do set fire to it, Im just going to let it burn out as its helpfully completely out the way of anything flammable out there :D

A.K. Boomer
09-25-2012, 04:52 PM
Fasttrack all I can tell you is I had to bore a hole into my existing chimney and I did what you said - lots of little 1/4" holes all the way around in a circle (with a carbide tip mas. bit) - I then chunked out the inner structure and it went perfect,
my holes were all very straight and almost connected - really was a thing of beauty - then I just ran single wall pipe all the way inside the brick chimney - very safe even if you had a stove pipe fire it would still be contained...

kwoodhands
09-25-2012, 06:20 PM
I imagine you would like to have an ash dump door on the outside of the chimney.Measure to the center of the flue or drop a plumb bob outside the chimney. Drill thru the chimney with a long bit.
Hold the drill square to the chimney face and level. Go thru the walls to locate the centerline. Expose the masonry and drill a series of holes that you can tap out.
The hole on the outside will be enlarged for the ash door.
You can make a bit if you cannot find one long enough.3/8" drill rod with a pointed end will work.The point is just to dimple the flue to hold it on center.Have a helper hold the drill rod after you turn it in a little.Then remove the drill motor,tap the drill rod thru the wall.
You can get fancy and make a sort of star drill or even weld one onto a length of any steel rod.
I did this before with just the drill rod.
mike

Fasttrack
09-25-2012, 06:46 PM
Oh and having worked on a few dodgy houses, I *really* wouldnt make the assumption that the flue is going to be plumb to anything.

Well, you are probably right but this house was built in 1960 by one of those "last of a dying breed" kind of guys. WWII veteran, could do/make anything, had his own excavation business, made pewter belt buckles as a business, flew airplanes, etc. I feel privileged to own his house; he really did a great job. Whatever he didn't do himself, he traded labor for. I've even got all the original receipts for work done on the house ... they were scratched in pencil on the backs of various scraps of paper and read something like "xx hours for labor for Paul". Even my home inspector was surprised by the level of subtle quality. I've been doing a lot of work to it to update it and repair peripheral things (e.g. replacing the 1958 "coral" colored enamel sink and bathtub), but the structure is really solid. If the rest of the house is any indication, the flue should be plumb.

(Alright, I just had to brag on this guy and his [my] house a little :) )

Thanks for the encouraging words, everyone. Sounds like I'm not the only one dumb enough to do this myself ;) I do have a copy of the state building code and intend to follow it. I just don't know what to expect.

wtrueman
09-26-2012, 12:01 AM
Hi Fastrack: I built my house and put three flues in also. About 20 years ago, I "finally" realised the living room fireplace, beautiful as it is/was, makes the place TOO hot. Since then I have used the basement fireplace to heat the house (1420 sf per floor). The upstairs fireplace was neat for the kids to run to after the bath but the room would be 80 plus degrees by 5 in the winter afternoon with the basement cold. Kids now gone, grandkids come to the basement after a bath. The third flue? Used it as a sauna. Again until the kids left. My .02, Wayne.

Fasttrack
09-26-2012, 12:44 AM
Hi Fastrack: I built my house and put three flues in also. About 20 years ago, I "finally" realised the living room fireplace, beautiful as it is/was, makes the place TOO hot. Since then I have used the basement fireplace to heat the house (1420 sf per floor). The upstairs fireplace was neat for the kids to run to after the bath but the room would be 80 plus degrees by 5 in the winter afternoon with the basement cold. Kids now gone, grandkids come to the basement after a bath. The third flue? Used it as a sauna. Again until the kids left. My .02, Wayne.

Thanks, Wtrueman! I grew up in a modern house with a natural gas furnace. It had a fireplace, but it was on an exterior wall with the chimney on the outside. It heated up that room ok, but it was not a practical heat source ... just for aesthetic value.

Consequently, basement fireplaces seem strange to me. I never would have guessed that it could provide so much heat. I'll have to install a liner to use it, but it may get quite a bit of use after all.

Seems like a lot of basic knowledge is lost because of "modern technology".

wtrueman
09-26-2012, 01:51 AM
Fastrack: I forgot to mention that my chimney is in the center of the living room not at the outside wall. This really makes a difference as to the heating. Wayne.