Cutting in New Thimble

I'm getting ready to cut in a new 8" thimble into an 8"x12" brick and tile chimney. On the opposite side of the chimney there already exist an 8" opening. This is at my sons house and he is worried that the chimney will somehow be weakened and maybe damaged if we don't close up the existing opening first. There is also a half brick opening in the 8" side of the chimney where a gas water heater was. Both of these opening are going to be closed up as they will not be needed but I wanted to leave them open to have access to the back side of the new opening. The question is what do you guys think, will cutting in the new opening first have any detremental effect on the chimney? BTW the chimney is in excellent condition. My son lucked out and bought a 1950's vintage house that was always well taken care. He is planning to install a used Vermont Castings "Defiant" wood stove that is also in very good shape.

Thanks for your opinions
JB

Just wondering why can't you go in the opening that is already there?

The new hot air gas furnace is on that side of the chimney. The previous owner had it installed to replace the old oil fired furnace. The new furnace is direct vented out the back wall so that only left the old gas water heater on the chimney and he just replaced that with a new gas fired tankless water heater, direct vented. The only good place to set the wood stove is on the side with no thimble.

Jeff, if the old thimble is still cemented in place, no cracks, then the chimney should be structurally sound. Maybe I missed it, but does the chimney go up thru the middle of the house, or is it on an outside wall?

the chimney should be fine . are you going to be cutting or useing a jack hammer ? cutting will cause less vibration .

I'm going to be using a 1/4" masonry bit in my hammer drill and drilling closely spaced holes and then hammer and chisel. This way like you say, less vibration and shock to the chimney.

Thanks.

Chris, the chimney goes up the middle of the house. It's about 30' high and would make a nice coal burning chimney but, I couldn't conveince the lad to burn coal. He was with me in my shop last season and experianced a little puff back on the Chubby, scared him off from burning coal. What a shame.

JB Sparks wrote:I'm going to be using a 1/4" masonry bit in my hammer drill and drilling closely spaced holes and then hammer and chisel. This way like you say, less vibration and shock to the chimney.

Thanks.

Good idea, the holes don't have to be too close together, though. Then when you finished drilling the holes, use this blade in you SawZall to "connect-the-dots".
http://www.amazon.com/Milwaukee-48-00-1420-Carbid ... B002AYDESO

That's funny Chris, I have those blades but didn't think about using them on this job, Thanks.

My son has come around to my way of thinking.....finally. Shesh... doesn't he know "father know's best".

Not bad...
Only took him 8.5 hours to see the light...

Ha, I thought that was a little slow on the up-take.

LOL, I knew I wasn't putting wood in when I got a house, I spent way to much time cutting and spitting at a boy scout camp to have that figured out. Generally i'd say a good 6 hours of splitting and ranking changes opinions.

sharkman8810 wrote:i spent way to much time cutting and spitting

I hear that loud and clear.

I'm still cutting and splitting. Hey, its free. I admit I did get a log splitter 10 years ago, but that has paid for itsself by now, at 10 to 12 cord a year. Next house will be strictly coal-heated.

Jeff, let us know how the new thimble works out.

Try again to talk him into getting a stoker

DVC500 at last wrote:let us know how the new thimble works out.

Will do, Chris.

DVC500 at last wrote:Try again to talk him into getting a stoker

I think I'll wait for him to come to me and ask about burning coal again...after he has a season of running down every 6 to 8 hours to refill the wood stove. He did get a good deal on a couple cords, I think he said he paid 160 a cord. That won't happen to often.