New Steel Liner - Old Flue Creosote

[vote4pedro]

Hello,

Previous owner of our new home did not keep up on the chimney so there is a nice layer of glazed creosote, which smells in the summer despite a chimney cap. So we are attributing the smell to humidity.

We are adding a wood buring insert and are going to re-line the flue with stainless steel to the top of the chimney. The place where we're buying the insert, as well as our chimney sweep said not to worry about removing the glazed creosote since we've had the chimney cleaned (but not chain whipped).

I have 2 concerns about not cleaning the chimney. First is, every document I've read regarding installing a liner has said to have the chimney thoroughly cleaned, including creosote removal. Second is the smell, since I don't think it's caused by rain.

Any advice? I know it's better to be safe than sorry, but a chain whip cleaning isn't cheep.

Thanks,
Mike

 

[Eric Johnson]

I guess I would try to burn it out of there if it really bothers you. In my opinion, if there's only a glazing, any chimney fire you are able to get going won't have enough fuel to do any damage to the chimney, although I suppose you run a slight risk of an internal fire that could cause problems if the chimney is in poor shape.

 

[shredney]

Whoa Mike,

Do NOT listen to anybody who tells you that you don't have to clean your chimney prior to installing a stainless steel liner in it. This, all to common practice, is a huge risk. I have witnessed houses burn when the creosote between the SS liner and the brick catches fire. If it does you have no line of defense to protect you, and when the fire department shows up they will have great difficulty extinguishing the fire because of reduced access to it. This is not a good choice to make to save money. Instead of chain flailing the brickwork, look for someone who uses Cre-Away. This is a dry powder type of catalyst creosote remover. We have used it for over 15 years and it can be very effective and mess free. I am glad to see someone do a full reline for their fireplace insert, this is the very best way to vent an insert. So I congratulate you on that, just make sure the chimney including the smoke shelf is very clean. As far as smell, if a blocker plate is installed at the throat you should have no smell.

Later, and good luck

 

[shredney]

PS Mike do not let anybody "Burn" out your chimney to clean it. Any Sweep worth his salt would never consider this. And anyone who thinks there is such a thing as a "controlled chimney fire" better have really good insurance and maybe might consider some professional training.

Good Luck

 

[Eric Johnson]

Well, I knew I'd get flamed or reprimanded for saying that. Best to follow the experts' advice, especially where fire safety is concerned.

Steve, I've operated wood-fired boilers hooked up to insulated ss chimney liners for more than 12 years and in my experience, small chimney fires are fairly routine (if unplanned) events that help keep the chimney clean. I also got into the habit long ago of running a brush up my chimney on a weekly basis, if for no other reason than peace of mind. Now admittedly, burning off a little creosote in a 7" ss liner is a somewhat different animal than torching off a small fire in a clay liner, but I think it's unfair to characterize burning off a little glaze as an "uncontrolled chimney fire."

 

[shredney]

Howdy Eric,

I know where you are coming from and congratulate you for burning wood. But he actually said " a nice layer of glaze" . Unfortunately I had a friend who was a chimney sweep lit his own glazed chimney to clean it as he had done for years, and caught his attic on fire because the brickwork, being unlined, couldn't hold the fires anymore and he came very close to losing his house. As it was his insurance company denied his claim based on his bonehead move. It was winter and he had no roof. So all his friends, including competing sweeps, pitched in one weekend and put a roof on his house. A tough lesson to learn but well learned. Seriously we have had tremendous success with Cre-Away over the years and were afraid a few years ago when they were going to close so we hoarded a bunch of it. Fortunately another company bought them out and it is still available. And yes a fire inside an SS liner is something else altogether.

Good Luck

 

[vote4pedro]

The folks doing the install said they would do a top plate, but not a block off plate. I do have a clay liner which seems to be in good shape. I've called 3 sweeps today and they all told me not to worry about the creosote. 1 of them said I should have the liner insulated to be safe in the off chance there was a chimney fire in the SS liner (which I would hopefully prevent with yearly cleanings). Apparently a chimney fire in the SS liner can radiate heat hot enough to ignite creosote in an existing flu.

The same person also told me it's nearly impossibly to truly remove glazed creosote and that it would eventually dry and fall down on its own in 5 years (considering the flue is no longer used). Is that true?

I appreciate everyones replies.

-Mike

 

[Mo Heat]

The folks doing the install said they would do a top plate, but not a block off plate. I do have a clay liner which seems to be in good shape. I've called 3 sweeps today and they all told me not to worry about the creosote. 1 of them said I should have the liner insulated to be safe in the off chance there was a chimney fire in the SS liner (which I would hopefully prevent with yearly cleanings). Apparently a chimney fire in the SS liner can radiate heat hot enough to ignite creosote in an existing flu.

The same person also told me it's nearly impossibly to truly remove glazed creosote and that it would eventually dry and fall down on its own in 5 years (considering the flue is no longer used). Is that true?

I appreciate everyones replies.

-Mike

Several of the resident experts here have stated it's very important to clean the old clay chimney before installing a liner. With no bottom block off plate a chimney fire (which even your guys admit CAN happen) will be like a blow torch coming into your house since the top is blocked and the fire will have nowhere else to go.

There is another expert around here named Shane IIRC that claims his stove shop has used a chemical product for years with very good results. It takes several applications with fires in between, but if it were my chimney, I'd at least give it a try. Maybe Shane will chime in here once this msg pops back to the top of the pile.