Author Topic: How to finish chimney in prep for possible wood stove. (Read 487 times)

Jeff · « **on:** May 09, 2022, 08:50:19 PM »

Right now, this is what we have in the photos. Im getting ready to stain the cabin, and want to fill that spot where pete tore out the stone chimney. He decided he didnt want to cut through the roof. That is masonary clear through. 6" thimble. How should I finish that to use a woodstove?

ljohnsaw · « **Reply #1 on:** May 09, 2022, 08:55:50 PM »

I'd remove the last few boards and do that entire section with river rock. Or slice a lot of pudding stones in half so you have a flat side to make it easier to mortar to the wall.

Old Greenhorn · « **Reply #2 on:** May 09, 2022, 09:15:44 PM »

Looks like you've got yourself a project there Boss! How big is the pier? Looks to be about 16" square? Are you saying you want to put a new chimney on the cabin? If so, it looks like you would have to cut out that gable for clearance. Or are you leaning toward a metalbestos (pre-fab) type thing?
I have no idea what 8x8x16 chimney block is going for around your area.
What are your desires with this?

Jeff · « **Reply #3 on:** May 09, 2022, 09:32:23 PM »

What Id like to do is, I want to put wood over it and use an insulated pipe out that thimble, is what I want to do. Secure it away from the roof using the screen porch.

Old Greenhorn · « **Reply #4 on:** May 09, 2022, 09:54:14 PM »

Well, maybe I am being too obvious here, but if you come out of the thimble with a metalbestos (or equivalent) tee to a support shelf, then run it up (you may still have to trim that gable a bit) the tee will allow for cleanout from below (no ladders). You could then box the whole things in with wood. Remember, even the insulated chimney is not zero clearance, but close.
Somebody who is actually good at this will come along soon with a real workable idea. I am just killing time and opening the discussion for their more pointed comments and thoughts.

I thought you already had a stove in the cabin?

Jeff · « **Reply #5 on:** May 09, 2022, 10:03:05 PM »

Its a ventless propane fireplace, but if push comes to shove, I have wood here.

Don P · « **Reply #6 on:** May 09, 2022, 10:08:42 PM »

Go to the suppliers website and download the installation instructions. I've been reading DuraVent's stuff lately. It'll tell how to build their thimble, shows the support bracket ,etc.

This is to a free read only of NFPA211, the code for chimneys and woodburners
NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances

Resonator · « **Reply #7 on:** May 10, 2022, 12:38:18 PM »

My best customer used double wall pipe for his hunting cabin stove, stays cool enough you can touch it when the stove is fired up. Stuff is pricey, you'll want to do some calculations to know exactly how much you need. The old rule of thumb was at 3' above roofline you measure 10' horizonal. From that the top of the pipe has to be at least 2' higher than that point, or 2' higher than the peak. (Check with a HVAC contactor or local code to be sure). My own experience adding extra height helps to pull draft when there isn't much wind, though a taller pipe requires more bracing.

SwampDonkey · « **Reply #8 on:** May 10, 2022, 01:23:42 PM »

No help to you, but looks like you're already jumping into projects up there.

Have a good time put'n in the time.

Bricklayer51 · « **Reply #9 on:** May 12, 2022, 09:01:18 AM »

its been 3 ft over peak in mi for quite a few years

Jeff · « **Reply #10 on:** May 12, 2022, 10:22:34 AM »

Well that aint going to happen,

breederman · « **Reply #11 on:** May 12, 2022, 02:14:53 PM »

As I recall there is a horizontal distance from top of chimney to the roof, over which you don’t need to be over the peak. Our insulated chimney comes up from inside the house on the north side of the roof, it’s shorter than the peak and has worked for over 30 years.

Don P · « **Reply #12 on:** May 12, 2022, 06:29:06 PM »

2' above the highest point within 10' horizontally is the code y'all are thinking of.

ljohnsaw · « **Reply #13 on:** May 12, 2022, 07:15:41 PM »

Quote from: Don P on May 12, 2022, 06:29:06 PM

2' above the highest point within 10' horizontally is the code y'all are thinking of.

OK, so he needs to go diagonally from the thimble to the eave then up! That will save a little.

Jeff, from the camera angle, it looks like you have a 12-12 pitch. It's not that steep, is it? If it is, then you'd be looking at 12' of vertical pipe above the roof line if the peak is 10 or more feet away. $:-\$

Jeff · « **Reply #14 on:** May 13, 2022, 04:45:47 PM »

Not sure of the pitch, but not 12 12 I dont think. Ill have to check.

Don P · « **Reply #15 on:** May 13, 2022, 06:54:37 PM »

Jeff, take a book or something square out in the end yard. If its a 12/12, 45° on each side, when you hold the book up, turned to plane with one side of the roof, the other roofline will plane in with the other side of the book. A 12/12 makes a 90° corner. A 10/12 will be 5° wide of the book on one side.

But, from the looks of it, 2' or better above the ridge is going to be the answer to the chimney top question.

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