How do I install a masonry extension to my chimney?

[WNCburner]

Due to advice given in another thread, I'm looking at adding some height to my chimney. Current height from the damper to the top of the flue is just over 10' in an interior masonry chimney. The manual for my insert(Osburn 1600) states a minimum flue height of 12'. I want to ensure that I have a safe set-up with plenty of draft, so I will be adding an insulated liner.

My question: How do I attach a stone and mortar extension to the existing chimney?

 

[littlesmokey]

Looks like the existing chimney could use some work. Have you thought about using a SS liner? May be cheaper and in the long run more practical. You would need to remove the stone cap and cap each flue, but it would solve your problems.

 

[WNCburner]

Yes, I had originally thought to run a flexible SS liner to accomodate the slight offsets in the chimney with rigid insulated pipe(like simpson duraliner) out the top to give me the extension I need. Does this sound reasonable?

 

[tiber]

Looks like the existing chimney could use some work. Have you thought about using a SS liner? May be cheaper and in the long run more practical. You would need to remove the stone cap and cap each flue, but it would solve your problems.

Seconded. I just redid the cap on my chimney but I left a spotlight in the fireplace when I did it to make sure I still had all the tiles, etc. (I promptly dropped an F'ing brick on there - not my best moment).

While the mortar was starting to fall out and the cap was cracked, the clay tiles were still in one piece and straight.

How about sticking your head (and camera) in there and making sure you've got all the bits and pieces you need?

 

[littlesmokey]

I'm not a stone mason, but if that were my work, I'd get a job at MacDonalds. You will need to cap the top completely. Don't know the style of the house, but looks contemporary. A nice copper cap, left to tarnish would look great. Have it cover far enough down the outside that you don't have to worry about drip-back problems. Custom cut the opennings for both caps. Offset according to local codes (heighth difference for different appliances and fuels). I'd use black caps (my preference) make a fine looking finish.

 

[WNCburner]

I'll have to take a closer look after the sweep has his way with it.

 

[littlesmokey]

Just from the pic, looks like a liner job to me. SCARY :gulp:

 

[WNCburner]

I'm DEFINITELY installing an insulated liner. I appreciate the advice and ideas for a full cap...the copper idea would look great, I agree. My question has to do with extending my flue height--10' isn't going to draft well, the manual for my unit calls for at least 12', and I don't quite have the 3' needed above the roof. What should I do?

 

[tiber]

If you're installing an insulated liner, you don't need the clay tiles since you're now just putting the liner into a chase. Don't let them talk you into replacing the clay tiles.

Does the other flue go down to your existing oil furnace or similar?

I would get rid of the slab and the legs on top of the chimney, then I would go to home depot/lowes/the internet and find a chimney pot you found attractive. Given that you're only looking for another two feet, you should be able to find something attractive which will also line up with your flue. Then simply mortar it into place and build up the crown a little, put a spark arrester or cowling on top and you'll be much better off.

 

[WNCburner]

tiber- thanks for the idea and the great illustration...that might be exactly what I'm looking for. To answer your question, the other flue goes to a fireplace in the master bedroom which I won't be using anymore. Had originally intended to put a small woodstove into the fireplace(jotul 602), but after reading some threads here I've realized that isn't a good idea(or code friendly) to have a solid fuel burning appliance in a sleeping area. Thanks again for your ideas.

 

[WNCburner]

littlesmokey and tiber, THANKS! I do appreciate your responses. I'll be sure to post some updated pictures that hopefully aren't as SCARY as the interior chimney shot I posted.

 

[littlesmokey]

littlesmokey and tiber, THANKS! I do appreciate your responses. I'll be sure to post some updated pictures that hopefully aren't as SCARY as the interior chimney shot I posted.

That's the pic I'm talking about. Here it would be a teardown. The inspector would not let it be used and require it's removal, or complete blockage (concrete pour). Do not use either stack. PERIOD.

 

[WNCburner]

We don't use 'em. There were some 1980 slammers installed when we bought the place(apache stove) but the inspector warned us about using them, and we decided to look into the best way to make them safe to use. Our chimney sweep agrees with the members here---insulated liner.