I need to remove and replace an existing masonry chimney that is falling apart. I will be redoing the roof this week and the chimney passes through the overhang.
I am not a Mason! I’m not a roofer either…but that’s another thread.
I started out by searching for double walled steel systems online. I see a lot of them in my area.(northern NY).
I read that the metal chimney should be enclosed in a chase. Is this the norm? most around here are not. Do you know if it is in the residential code?
My masonry chimney sits on a “bump out” built with the foundation, with the flue from the Oil Fired Boiler coming up through it via the foundation wall. How do I attach a steel chimney on to it? All the Web sites show elbows coming through walls with clean outs, which won’t work. Some show an adapter used to “extend” a masonry chimney with a steel one to give it more height….Do you think this would work?
I have sent e-mails to a couple of the company web pages, but no response yet. The one industrial store that carries the SS Pipes is not open on Sunday and Monday.
Thank You Ward
Replies
Just based on a couple of stories from friends plus some Habitat work, I think it depends a bit on the way the chimney is "listed" -- double wall units should be enclosed in a chase (reasonably airtight drywall), triple-walled units may not require this.
Consult both the mfgr's instructions and local code people.
Not really, Dan. Based on different designs, a class A chimney can be double or triple walled.The first Q is whether he needs a class A or a B chimney. If this is only serving an oil or gas fired appliance, a B flue is all he needs.Neither need to be enclosed in a chase in most circumstances, but it is often adviseable.For instance, with a wood stove and a class A metal chimney, if it is on the exterior as in this case, it will cool faster and creosote will build up more, requiring more frequent cleanings. A chase can modify the cold exterior temperatures. if the same class A chimney is run up the inside of the house, the codes might require that a chase be lined around it for fireblock safety purposes.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Well, I remember one Habitat house (a rehab) where I had to build a chase for a double-walled gas flue -- inspector required it.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
locale codes vary
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thanks guys, I Guess I'll have to wait until Tuesday and talk to the shop. I appreciate the advise. I should have planed better, I'll have to wait to take down the Chimney. Can't turn the heat off yet...23 deg this morning.
As my my Dad used to say.."Prior Planning Prevents Piss Poor Performance" should have listened..
Thanks again!
The Rule of the Seven P's :)
Watch the exposure to outdoor ambient with type B vent. Too much and you could have problems ranging from interior pipe condensation issues to a cold stack where the appliance won't be able to create a draft and vent properly.
The manufacturers generally recommend a chase, at least for long lengths exposed to the outdoors: see, e.g., http://www.selkirkinc.com/faq/index2.html#6There are 2 concerns: 1. If the air in the B-vent gets cold enough, it can keep the vent system from "priming" when the appliance lights off and lead to back drafting.* And 2: If the flue gases cool too much before exiting the flue, some of the moisture will condense inside the B-vent and can drain back into parts of the flue and furnace which are not designed to handle the corrosion from flue gas condensate.Local codes require equipment be installed in accordance with the manufacturer's instructions; the manufacturers' instructions require use of the GAMA vent tables; the GAMA vent tables are "guidelines" for "typical installations" and they provide that the person "designing" the flue system is responsible for proper operation.(In my area it is extremely rare for the installers to actually verify performance)----------------
*Remember, 80% gas appliances with "draft inducers" do not create positive pressure in the flue ("push the flue gases through the flue - they pull the air and flue gases at a uniform rate through the heat exchanger.
Fighting Ignorance since 1967
It's taking way longer than we thought
Well it seems like I will have to build the chase. All the chimneys I have looked so far says if it may get cold you may need a chase....and it does get damn cold up here!
I don't like the look of the pipe alone, but was hoping for a simple way out. I don't mind the work (actually love it), just that other job gets in the way. Guess I'll be framing into the evening
Went to the Plumbing and Heating Supply today, great place, very professional. Gave me a quote for just over $700 for an entire new metalbestos chimney. said I don't need to use a chase as long as it's a oil boiler.
Good news all the way around. Thanks for all the comments
Of course, never take the word of a salesman with regard to code.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
When I asked about Code he said "call the Inspector". I did...again. Small town, he has another job. He has never returned one of my calls in three years.
I'll just build to Manufactures Instructions. yes I read the Instructions....
Edited 4/11/2006 8:23 pm ET by ward121
>>The first Q is whether he needs a class A or a B chimney. If this is only serving an oil or gas fired appliance, a B flue is all he needs.I'm not sure what you mean by a "b flue" but it is my understanding you cannot use "B-vent" with an oil burner. The liner has to be staimnless steel, and you should use L-vent
Fighting Ignorance since 1967
It's taking way longer than we thought
I think RJW pointed this out, but at least in my area, B vent is not for use with oil. Stainless "all-fuel" vent is what is required. Hart & Cooley and Metalbestos both make a product, though not compatible with one another.
If your furnace is the only thing vented through the chimney, might you be better off getting a new high efficiency furnace that vents with PVC pipe, and just getting rid of the chimney?