Chimney Seperating from House

[andrsmith]

Please help.

I have a brick chimney that was added to the home after the home was initially built. It appears as if the chimney has shifted away from the house. The seperation is between one and two inches and pretty consistent from top to bottom. I had someone out to clean the chimney last year and they said the chimney lining was cracked. Their suggestion was to not use the fireplace until I have the lining replaced and seal the outside seperation. Others have suggested from doing nothing to tearing it down and rebuilding it. See attached pictures.

What are my range of options and what should these options cost?

 

[Shane]

Yes post the picture. Technically there is supposed to be a 1" separation from the chase to your house. If memory serves NFPA211 allows for this to filled with a noncombustible trim for aesthetic purposes. Usually if it's settling and separating from the house the gap is larger at the top than the bottom.

 

[wg_bent]

download and use picasa to change the pic size

 

[berlin]

i'd say your probably fine loooking at the pics, as long as the chimney structure itself is not cracking and its not leaning. As far as the liner somewhere possibly having a crack in it... if its a fireplace chimney, don't worry about it, it will not be an issue. use it and enjoy it.

 

[Shane]

How excessive are the cracks in the liner? It could just be perspective but it appears that the gap is larger at the top than the bottom. It looks like the chimney has settled a little bit. I would make sure that the firebox and facing brick don't have a gap between them now. I would have to beg to differ on Berlins advice that as long as it's an open fireplace the flue tiles will never matter. If they're hairline cracks I wouldn't worry but if they're separated (more than a dimes width) then it is definately cause for concern. My suggestion would be to install a wood insert with a liner. More efficiency and you'll beable to bypass the clay liner issue. As for the chimney settling I would recommend sealing the gap and keeping an eye on it. If it goes too far you may have to look at taking it down. I've seen a couple of them jacked up to. Those are both tasks I do not do so as far as cost I couldn't say. For the insert installed though rough guess would be 2-4k.

 

[Michael6268]

Looking at the pics it doesnt look that bad, but maybe in person its worse. I have seen a few houses in my area that had a much larger separation, and they ended up puting large steel or iron straps bent to the profile of the chimney and attached to the house. Seemed to keep it from worsening. I know in earthquake prone areas they do this and actually sister it into the house, and attach it to several ceiling joists in the attic. I dont think that much would be structurally necessary in your case, but if done that way, you would eliminate seeing some of the steel on the house. If you are like me and like the open fireplace, allbeit a major heat loss, have sweep look at it and if needed install a liner but keep the open fireplace. Good luck.

 

[elkimmeg]

my guess is there is a couple of things going on. The initial footing that supports the chinmey is inadequate it has settled or experienced frost heaving. Second concern I am willing to bet inadequate wall ties, not enough or none at all, were used to bond the bricks to the structure. I also noticed that your chimney height also does not satisy code it should be 3' above any part of the roof and one cannot count the height of the clay liner as that is not a complete chimney.

Few qusetions need to be answered to get more info. How long has this condition been going on? Is the separation getting worse?
when did you first notice it? Were there any major weather events like real soaking rains of extremely cold winter where frost drove deaper the normal?

 

[elkimmeg]

There are two solutions to building a chimney footing one being the footing is sitting on the foundation pour,
the best support way. The second:a footing not part of the foundation poured to support the chimney. It is my guess,
this is the case in this situation, and yes that independent footing can settle or move.

After reviewing the pictures again

Dylan
I stick with my original observation the chimney is ,but 2 bricks rows above the side roof, not 3' or about 14 rows worth of brick

 

[elkimmeg]

If the footing has finished settling, then Michael6268 has offered a solution of support brace straps.
If the footing has not come to a complete rest and is sitting on poor bearing materials that do not compact well,
conditions will never improve. A correct footing and compacted material would be necessary to solve your situation. A complete take down and rebuild, The footing has to be below frost re-enforced with re rod and pinned to your existing foundation. and inspected to make sure all of the above. From afar, at a key board, I can not determine your situation. My suggestion is not to just look at the liners but has the ground settled around the chimney foundation? I would get a few opinions from reputable masons possibly your building inspector

 

[elkimmeg]

There is another major concern moisture getting behind that chimney. If this is happening, it will not be long before decaying rotting wood, will lead to major srtuctual damage. Depending upon your climate snow and ice can get in there. Water will freeze and thaw, each time freezing can push that the chimney, widening the separation. If you ignore the situation and allow adverse conditions to continue, your cost will exceed just chimney replacement, structural rebuilding. Ants and termites also thrive in moist enviroments, should moisture be trapped behind that chimney.

Further thinking about your situation. I believe your footing is failing to support the chimney. Movement can and will cause liners to crack and separate and cause the chimney to pull away from the home. You have not gotten back, but the tell tale sign is examining the ground around the chimney If it has settled and pitches down towards the chimney, look no further the footing is failing. Nothing can be done to correct a failing footing, without a complete take down and rebuild, starting with a footing construction, I outlined in a previous reply. Not the news you wanted to hear

 

[Harley]

Not to go off topic, but a question for Elk.... I do understand the 3' rule, but why does the "extended" tile liner not get taken into consideration? I realize that is probably in the code, but I only wondering why, from a safety/structural standpoint? Is it because of the relatively "weak" material the clay tile is made of? Is it more of an insulation/draft issue? Just a question that came to mind as I saw what you were referring to in the picture.

 

[Shane]

By code the flue tile can only stick out of the top of the chimney 1" or 2" I cannot remember the specific length.

 

[BrotherBart]

By code the flue tile can only stick out of the top of the chimney 1" or 2" I cannot remember the specific length.

One of the two tile linings in my chimney sticks up over a foot and has thermal cracks in it from it being freezing cold up there and then us firing up the stove.

 

[webbie]

By code the flue tile can only stick out of the top of the chimney 1" or 2" I cannot remember the specific length.

This code is probably the least adhered to in the modern world. Look upwards and you will see at least 3/4 of them are higher than this. Tile liners crack just from exisitng, let alone the many strains on them. The code specifying this 2" was something that was thrown together by someone from the chimney sweep org and pushed through (heck if I know why).

After all, chimney pots made of the same material as flues stick up a few feet. Clay roof tiles are also the same material.

I'd say, as a rule of thumb, keep them under 6".

As far as extending the liner out, this is a job for those Extendaflue chimneys of mass construction.

 

[BrotherBart]

By code the flue tile can only stick out of the top of the chimney 1" or 2" I cannot remember the specific length.

This code is probably the least adhered to in the modern world. Look upwards and you will see at least 3/4 of them are higher than this. Tile liners crack just from exisitng, let alone the many strains on them. The code specifying this 2" was something that was thrown together by someone from the chimney sweep org and pushed through (heck if I know why).

I know why. I have to stand on tip toe to look down my chimney and shove a brush in it. That sweep just wanted to be able to stand flat footed on the roof and work.

 

[elkimmeg]

Many masons cheat a bit they extend the liner to reach the required height. However Shane is correct, a clay liner is but that, a liner, it was never made to withstand the heat and temp differences un protected. Code only allows the liner to extend 2" beyond the chimney cap. Brother Bart provided the perfect example of an unprotected clay liner, to the elements and heat.

 

[Shane]

Yeah I can definately recall many that are much more than 2'. In fact that's one of my competitions favorite methods for extending chimneys to solve draw problems or offset flues. He'll just stick a 12-24" flue tile on top and silicone it down. On average in our neck of the woods the flue tiles range from 2-6" out of the chase. Since local jurisdictions can alter code I'm sure this one get's largely ignored. (obviously)