Cracked Fireplace Flue Lining

[harvman11]

Hello,

I recently bought a home with a brick fireplace (I think the fireplace was built in the 60s or 70s, so 40-50 years old), and today I had it cleaned and inspected. The inspector found cracks in the tile flue (he said evidence of previous chimney fires), and didn't really give me a straight answer about the safety in its current condition. He told me that to cover himself legally he couldn't recommend we use it in its current condition, and went on to talk about replacing the flue with a steel insert.

I don't doubt the intentions of the sweep, I think they were very professional, it was certainly not a high pressure sales situation or anything, I just think he didn't want to say something that could legally get him into trouble, which I completely understand. I'm not opposed to putting in a flue liner, but I'm not in a situation where I can do it now, and I'd like to use my fireplace.

So, my question is essentially this: is it dangerous for me to use my fireplace, in its current, sweeped-but-cracked condition, at least in the short term (the rest of the winter)? I've attached a couple pictures of the damage he indicated, thanks in advance.

Also, if this isn't the proper place to ask such a question I apologize, I'm new here.

 

[BridgeMan]

If $$$ is tight, I'd recommend borrowing on your place's equity if you're in a position to do so, and invest in a properly-installed liner. Having the place burn down because you want to burn some wood won't be any fun, and getting future homeowners insurance will be difficult, all because of a poor decision having been made.

On the other hand, if the only damaged flue sections are near the top, they are a fairly simple DIY-er replacement job. I replaced the top 2 sections of a 25-yr.-old place a few years ago, and extended the chimney 2 more sections for better draft. Took more than a few weekends including the c.i.p. concrete cap, but it was not a difficult project. Had to use a special, heat-resistant mortar to set the tile flues (stuff came in a large can). Finding matching brick for the outside was the biggest challenge.

 

[user 4883]

Based on the pics shown, I don't see any reason why you could not continue to use the fireplace. Just my opinion and I'm no expert on chimneys.

 

[nealtw]

One visiable crack should show the need for a camera inspection, Cracks allow heat to get to the brick and morter which can not take the heat. The brick will crumble from the inside out, and dosn't show up until it is to late. We don't know how long the cracks have been there. I would not use the chimney.

 

[paul52446m]

A few cracks don't hurt. If you have big piece of clay liner missing then heat could get to the brick.
Clay flue liners are made not to cement in. They should just set on top of each other.
This way the can expand with out cracking. If you cement them in then they will crack.
The up draft in the chimney stop the heat from going through the cracks. Paul

 

[Shawner]

If you can't get it signed off on by a sweep, I wouldn't use it.

Plus, a fireplace won't give any appreciable heat into your home... you might want to consider a wood-burning insert if you're looking for an alternate heat source. But, then you'd need a liner. Check on hearth.com, lots of good info there.

 

[user 4883]

It's my understanding that a fireplace will actually suck more heat out of the home than it generates into the home.
Thus the wood-burning stoves were/are very popular.

 

[inspectorD]

Bottom line, you need a new liner and a chimney cap. If you are not going to use this I would put a cover on the top to keep the rainwater out for long term.
Fireplaces have a negative effect on your home, heat loss is a big issue. Expecially when you have a fire, you suck all the already heated makup air to burn the actual fire, out of the home. Getting an insert or woodstove is way more efficient.
And yes your sweep is correct. The signs of past fires is evident at that top flue, even some creosote is still visible because it is impossible to get it all off.

Better safe than sorry.

 

[Precision Home Services]

The cracked liner is unsafe to use! The steel liners will make the flue opening smaller if they just insert them in the existing liner. The better repair method would be to remove the existing tile liner and then install the steel liner and pour a special mixture around the liner.
Did you have a professional home inspection prior to purchasing the home? If so, what did the report say? If it was inspected then the inspecter didn't look in the chimney and he may be liable for not finding the damage. I usually recommend further evaluation by a reputable chimney co when I can't see down past the first couple tile liners. This goes into the settlement agreement and puts the seller on notice that there may be damage and may require repair or reimbursement. The seller did not disclose that there was previous chimney damage and you should discuss their liability for failure to report the damage. The seller's insurance company would have paid for repairs had it been reported and you should explore that now even though seller doesn't own the home at present. Your insurance company will not cover the repairs since it occurred prior to your ownership and may not want to cover any damage caused by fire until it is repaired.
Good luck.

 

[Michaelolding1]

The purpose of your liner is and a dead ain't space around it is to provide an impervious surface for flue gases to escape along and to prevent heat sink into the surrounding masonry. More importantly though is that a cracked tile can fall in during a flue fire blocking the flue which can create a very dangerous situation depending on hot the fire is.

Either replace the tiles with drop tiles, cast in place system or stainless steel. A 10" round will equal a 12" square. Don't take the chance on a damaged flue system.

 

[BridgeMan]

. . . . A 10" round will equal a 12" square. . . . .

For anyone who's interested--a 10" round has a net surface area of 78.54 sq. inches, while a 12" square has a net surface area of 144 sq. inches (not counting a slight rounding deduction at the corners).

Not quite the same. While the circular shape may be more efficient than a square in venting flue gases, I doubt the 10" can make up for the 54% net area deficiency it suffers compared to a 12" square.

 

[paul52446m]

For anyone who's interested--a 10" round has a net surface area of 78.54 sq. inches, while a 12" square has a net surface area of 144 sq. inches (not counting a slight rounding deduction at the corners).

Not quite the same. While the circular shape may be more efficient than a square in venting flue gases, I doubt the 10" can make up for the 54% net area deficiency it suffers compared to a 12" square.

Some people have a hard time with math! You are right ,if you have a regular size fire place you should have a 12 x 12 clay liner. The man should check and see if the clay liners are cemented in. If they were cemented, then that why they are cracked. Clay liners are suppose to just set on top of each
other so they can expand and contract with the temp change. The joints between the clay liners do not need to be sealed. Heat will not go out through the seems, the draft in the flue will draw air in through the cracks. Paul

 

[Michaelolding1]

Most clay liners average maybe 10 1/2" x 10 1/2" effective inside area for a nominal 12 x 12 flue.

A round flue is more efficient due to the nature of fluid dynamics and most drop in flue systems measure the flue inside diameter not outside diameter like is done on the clay tile so the actual effective area of a clay tile is about the same as a 10" steel sleeve.

It is likely that by the time you deduct the joints and inconsistencies of a clay lining system that any seamless round flue will be more efficient than a square tile flue.

 

[BridgeMan]

. . . so the actual effective area of a clay tile is about the same as a 10" steel sleeve.

Sorry, but the numbers don't quite add up--a 10.5" square tile flue has a surface area of 110 sq. in., compared to the 78+ sq. in. of a 10" round, meaning the square flue is 40% larger. And you're not being very realistic if you think the round steel flue will have no joints, offsets or other interior irregularities. I've looked at dozens of round pipe flues over the years, and have yet to see one that's one clear, straight shot from bottom to top.

 

[Michaelolding1]

Smoke rising in a flue travels in a circular pattern so the corners of your clay tile are effectively useless which must be deducted from the over all total. Really it isn't so much the area as it is the location of the chimney in terms of surounding topography, prevailing winds, etc and most importantly the chimney height. The difference in air pressure between the ground and the top of the chimney is a lot more important to adding draft.