Suggestions for a chimney fire proof chimney

I am in the planning stages of building a chimney for my garage. I haven't figured out how many flues I am going to put up yet, but it will be at least 2. The chimney will be of masonry construction. The garage is 2x6 balloon framed, built in the 1930s, i.e. well seasoned. I plan to be heating the garage primarily with coal, but I would like to have the option of burning wood as well.

I want to build something that not just meets, but far exceeds any safety requirements. I'm talking about the chimney that is so robust, that if you have a roarin' chimney fire, you sit around, drink beer, and make youtube videos of it, instead of having to call the fire co and worry that your shop is going to burn to the ground. I'm exaggerating a bit, I wouldn't sit around and watch a chimney fire for fun, but I want a very high margin of safety built in.

I've been trying to think of ways to do this. One thing I thought of, would be to put some type of insulation (vermiculte?) between the brick and a 12"x12" liner, then put an 8" round liner inside the 12x12 and put more insulation between the 2 liners. Any other suggestions?

Thanks

I suppose you could build one out of three inch thick cast iron pipe but that won't help much when your roof is on fire. Build a tile chimney and keep it clean and you will have no worries.

Round flues draft better and stay cleaner than rectagular or square flues. I used 8" block to surround a 8" square flue. If you can find the round ones it would be better.

Phil May wrote:Round flues draft better and stay cleaner than rectagular or square flues. I used 8" block to surround a 8" square flue. If you can find the round ones it would be better.

Yep, I did mine in 8 inch round, they have male/female ends so they fit together well.

A chimney-fire-proof chimney? That's easy.

Burn coal, and nothing else. WHALLA! ZERO chimney fires.

SMITTY wrote:A chimney-fire-proof chimney? That's easy.

Burn coal, and nothing else. WHALLA! ZERO chimney fires.

Can't argue with that..

Round is the way to go. For wood, masonry chimney , ss liner with poured insulation, clean it regularly. Coal is less fussy, no
fire going to happen, but will benefit with consistent draft from the heat retention of the insulated lined chimney. Over build is
good, but pricey.

SMITTY wrote:A chimney-fire-proof chimney? That's easy.

Burn coal, and nothing else. WHALLA! ZERO chimney fires.

Yeah, that's the plan, in the house anyway. It's UNLINED so nothing but coal will be burned.

I shouldn't admit it here, but the dirty truth is, I DO enjoy having a wood fire on occasion and it would be nice to have the option when I put up the new chimney.

A chimney fire proof chimney uses firebrick of 4" nominal thickness min. as the liner material. You need to lay it up w/ alumina mortar (heat stop is a common brand) and you need to have a 4" space between the "liner" and the brick chase filled with vermiculite. With a chimney of this construction, you can build chimney fires for fun.

Berlin wrote:A chimney fire proof chimney uses firebrick of 4" nominal thickness min. as the liner material. You need to lay it up w/ alumina mortar (heat stop is a common brand) and you need to have a 4" space between the "liner" and the brick chase filled with vermiculite. With a chimney of this construction, you can build chimney fires for fun.

Ok now we're talkin'!! Since the labor is free, I can spend a little more on premium materials. Thanks!!

Don't they have anything you can seal it off so it doesn't get any air?

I have theses SS caps on my Chimney that are fairly robust and I'm thinking if I had a fire and got them closed it might put it out or at least restrict it a lot.

Richard S. wrote:Don't they have anything you can seal it off so it doesn't get any air?

I have theses SS caps on my Chimney that are fairly robust and I'm thinking if I had a fire and got them closed it might put it out or at least restrict it a lot.

That looks like it could help slow down a chimney fire. I had also wondered, though, if restricting the air intake to a blazing hot creosote fire could set up conditions for a puff-back like event. I suppose though, if you had the air supply restricted at both ends, and kept it that way until the flue cooled down, that wouldn't be an issue.

The house is certainly going to get smoked out which is better than the fire but not by much. I guess another issue might be the fire seeking oxygen the next location which is the fireplace itself. I'm going to have to research this further and get some opinions.

If you want a tight sealing flue damper, place it in the lower part of the stack and use a heavy "pie plate" of 1/2" thick steel. I use this design on rumford fireplaces and it seals perfectly and it's very simple - this can be built into a flue even when not used above a fireplace.

This is a pic of the firebrick base built for the sliding "pie plate" damper.

in
stead of spending all that money, go out once and buy a chimney cleaning brush and a few rods and clean it a few times each season..when i burned wood i cleaned mine every month took 1/2 hr.i never had any problems, operated that way for years...i live to far from fire co. to have chim fires...