I looked at a chimney today. House is vacant. I’m supposed to get back with the owner on redoing the chimney flashing, install a cricket, etc.
But while I’m up there I can’t help but notice that the chimney cap is in poor condition and a lot of the bricks are spalled (especially at the corners).
Is there any point in pouring a proper cap without doing something about the spalled brick?????
I suppose a spalled brick can be removed and replaced without taking the chimney down to the brick, but what percentage of the bricks are damaged before it is better to just take the chimney down and rebuild it???
Thanks.
Rich Beckman
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Replies
Spalling can be due to:
A. Poor brick quality that allows excessive water absorption throught the face and then freezes to pop off the front of the brick.
B. Leaky cap stone/cast concrete or split/absent flue tiles...results as above.
C. Gas combustion moisture condensing on an oversized or cold flue-same results.
D. Other items that do not come to my mind at this hour!
Yes, single bricks can be cut out and removed. Cosmetic effects will be from difference in brick and mortar colors. Comparison of estimates for complete tear down to roof level and/or (?) below as opposed to "cut & replace" approach.
Next week I will do a final walk-thru on a "cut & replace" job on a local municpal building....approximately $150k. The cause was two fold....exterior wall bricks with too low of a production temperature at the fired faces as well as migration and condensation of moist interior air at the parapet cavities. Both conditions allowed for frost spalling.
The parapets were damaged to greatest extent at roof level and were demolished and replaced with steel stude, insulation and DriVit finished surfaces rather and "cut & replace".
................Iron Helix
Rich,
A good picture would help us determine what might be required so that our advice might have some merit.
Walter
The rooftop bordello and ranch fallin' apart again? ;)
How old is the house or more accurately, how old are the bricks? If they're old soft bricks, a lime mortar should have been used. It may be that the chimney has been repointed with a modern Portland cement based mortar ........... the mortar is stronger than the brick so the bricks fail first (spalling).
http://www.cr.nps.gov/hps/tps/briefs/brief02.htm
Agreed, and the subject of lime mortars has been kicked around here before, I think.
Problem is, try wading your way through the internet sellers of lime mortar, figuring out what you need, & coughing up the $$.....it's no surprise that it usually gets done with sackcrete.
I'd love to be able to get the "right stuff", or mix it myself out of locally available materials...
There are several reasons for brick to spall in a chimney. One not fully mentioned yet is water intrusion (due to cap problems) followed by freezing. [OK, on re-reading I see this was mentioned.]
Depending on the construction, the spalling may be superficial and of no greatb consequence structurally. Or not.
Edited 3/22/2007 7:44 am by DanH
Thanks for the responses.The house is maybe thirty years old. The front of the house appears to be the same brick as the chimney (but the front is painted) and those bricks are in good condition.The chimney bricks that are below the roof eave are in good condition.The cap is in poor condition.So I don't think it is far fetched to believe that the spalling is from the bad cap.I'd love to post a pic, but I'VE LOST MY CAMERA PHONE!!!!!!!!!!! ARRGGGG!!!!!(sorry)
Rich BeckmanThis signature line intentionally left blank.
We had one last year that was driving us nuts. Painted brick exploding. The Chim. was defunct and capped with a copper lid and as we were told, it was out of service.
We decided to vent it, by making a hole or a few with a 4" holesaw, and capping that with a lid...well, as soon as the first hole was made, we smelled both MOLD and oh guess what? Flue gasses...the Gas water heater in the basement was connected to the capped off flue!
There was a pair of fire boxes ( coal cookers) in line with that flue, but they were also shut off with sheetmetal at the damper location, so lucky the HO didn't die.
I haven't heard back if we fixed it or not, but I know we did the right thing.
Oh..you had a question..sorry. I haven't a clue.Inmate # 40735 At Taunton Federal Penitentiary.
"Oh..you had a question..sorry. I haven't a clue."LOL!!That's all right! Good story!
Rich BeckmanThis signature line intentionally left blank.
Since the building is'nt historical, I would try to talk to them into at least a rebuild from the roof line up if the chimney is in that bad of shape, one thing i've noticed on newer brick chimneyes when the brick starts to spalling it kinda grows like a cancer to the surrounding brick,more than likely with the bad cap there is a very good possablity that there is a lot of unseen damage.
Hey..did you missplace your drawl somewhere? LOL
Hows it going over there? We have red buds starting to pop.Inmate # 40735 At Taunton Federal Penitentiary.
weird ain't it! nope ,just talked to a socialolagist (sp) the other day! my sisters significant other. well anyway "she" said that the reason that my business has sort of tanked is the way I portray myself.--NO crap-- well ain't that calling the kettle black .I got my feelins hurt sniff- sniff, I told her maybe that was the very same reason she lost her tenure ,"she was my sissys professor"well any way , I,m trying to become more professional, -taking more showers- getting a couple more clean pairs of bibs- just basically keeping my mouth shut, to try to hide the hick.yep just waiting for the jobs to start rolling in ---any day now--heehaw- sorry slipped. not being myself is about to kill me . called up a couple of breaktime breathern a couple of weeks back just shot the bull some pretty nice- fellows- not fellers.see !I am learning.Yes ole Greenfield Webb -decorated civil war vet- diehard democrat-true southern mountain man is probably rolling under that pile of rocks they got him buried under -for one of his greatgrandsons is selling out his heritage to act and talk like a yankee...for a dollar.Shaaaammmmful it is.yess spring is here the college girls are starting to lay out at the park ,I have been taking my kids to - a lot here lately!ohhh my my.ohh oh yech I found out what spell checker was for.
Edited 3/23/2007 9:55 pm ET by dedubya
Yer as crazy as I am...now that there is a bad thing.. I love ya D.Inmate # 40735 At Taunton Federal Penitentiary.
"Spalled brick on chimney"
Where IS Spallchecker when you need her ???!?
And you would spell it how???
Rich BeckmanThis signature line intentionally left blank.
Don't you mean, "And you would spall it how???";o)
Hey, don't look at me, I'm mentally retireded.
Oh.Sorry.I'm slow.
Rich BeckmanThis signature line intentionally left blank.
Chim-chim-chimineeeSamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.