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Topic:   Masonry Chimney Lightening Strike - 2212 visits (1 today, 3 this week)

Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 15, 2005 07:40 AM            

During an inspection, I came upon this masonry chimney with the terra cotta flue liners cracked so bad I could see the damage from the ground, without binocs, while standing in the driveway. (PS: This shot taken with my new Canon digital camera that has a 12X optical zoom. Subject about 50 -60 feet away. Cool!)

Flues viewed from ground (107028 Bytes)

On the roof, the damge was much more apparent. The left liner is a cosmetic one filled with concrete that I believe may have cracked from trapped moisture freezing, or the crown moved and the liner wouldn't and so it cracked.

Top view of chimney showing left liner crack and crown damage(136848 Bytes)

The right liner serviced the only fireplace, located on the lowest level of this walk out basement home, and was cracked along with the crown.

Right liner crack(117264 Bytes)

Peering into the operating flue showed the top 2 liner tiles to be quite clean as if the fireplace was rarely used. The owner claimed to have rarely used it. I could see clearly the top 2 liners and both were cracked as in the photo, but beyond that the soot blocked view.

Inside the operating flue (126170 Bytes)

The owner contacted a chimney repair place who contacted me for a description of what I saw pertaining to damage since they did not get pictures. I explained everything and their assumption, over the phone, was damage from lightening. Said they were very busy rebuilding chimneys after some very severe storms blew through here last Oct/Nov and lightening damaged many chimneys.

Can't say as I believe their theory but it got me wondering just exactly WHAT lightening damage to masonry chimneys could look like. Lightening damage I have seen, to anything, has always involved some sort of explosion and throwing chunks or parts of the struck item all over the place. We have relatively little lightening strike activity around these parts but in Florida for instance, you guys are noted for extreme lightening storms. Does anyone have some pics of chimneys that have been struck by lightening and NOT been blown to smithereens? Could the chimney repair companys theory be correct here, based on these photos? I asked them to keep me appraised of the situation after examining the structure, just for future reference.

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Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

[This message has been edited by Bob Knauff (edited December 15, 2005).]

[This message has been edited by Bob Knauff (edited December 15, 2005).]

Michael Thomas
Member


Posts: 193
From:Evanston, IL
Registered: Jul 2005

posted December 15, 2005 08:13 AM            

> it got me wondering just exactly WHAT lightening damage to masonry chimneys could look like.

Me too. A quick GOOGLE turned up:

Hole in tile from lightning damage and missed by repair work:
http://www.tophatcs.com/8-25-03%20Hansen%20chimney%20003.jpg

In the middle of construction, a lightning strike ruptures the library's chimney:
http://urbanafreelibrary.org/blogpix/chimney.jpg

We were home at the time, but nobody was hurt. A battery operated toy dog in the kitchen spontaneously turned itself on at the time of the strike and started yapping:
http://tinyurl.com/7fjqa

And a bunch more...

[This message has been edited by Michael Thomas (edited December 15, 2005).]

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 15, 2005 08:40 AM            

The longitudinal cracks suggest a sudden thermal occurance such as a chimney fire. A Level II inspection with video scan would be in order to try and differentiate from construction defects, tree limb strike, freezing damage, etc.

Those lightning strike pics are a great essay. Shows the storm did them a favor. Look at how poorly that chimney was constructed. Can you count the defects?

Gotta go to West Va. Back Friday!
Bob

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Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 16, 2005 03:26 PM            

I should have noted in the original post for the guys down south, that the white stuff on the chimney is snow...not mold.

------------------
Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

Jerry Peck
Member




Posts: 7925
From:Pembroke Pines, FL
Registered: Feb 2003

posted December 16, 2005 03:41 PM            

"for the guys down south, that the white stuff on the chimney is snow...not mold"

Now you tell me, I've spent that last day awake trying to figure out what that was.

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Jerry Peck
South Florida

Rick Hurst
Member



Posts: 3810
From:Rockwall, TX
Registered: Oct 2003

posted December 16, 2005 06:42 PM            

Same here Jerry. I just figured they had a yard full of chickens.

Rick

Scott Patterson
Member



Posts: 3003
From:Ridgeland (Jackson), MS
Registered: Mar 2001

posted December 17, 2005 07:15 AM            

I had a lighting strike on my chimney several years ago. It took the top third off and ended up hitting a TV cable box in the neighbors backyard. Needless to say it traveled through the TV cable into six homes and fried many items in those homes. My home only lost the chimney as we did not have cable at that time!

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 17, 2005 06:02 PM            

A couple of years ago I ran a web search on lightning hitting chimneys. It turns out that there have been a lot of fatalities over the years when the fireplace blew out and chunks of chimney flew across the room like anti-tank rounds taking out people! I read stories from pioneer newspapers back in the early 1800s. Don't stand in front of your Fp during a thunderstorm!

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Richard Shaffer
New Member


Posts: 10
From:Marblehead, Ma.
Registered: Nov 2005

posted December 19, 2005 11:56 AM            

saw something similar a while back. In that case the chimny was severly damaged and black discoloration from the strike was evident.

Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 20, 2005 05:10 PM            

I did notice suspicious discoloration to the area directly at the top edge of the crack on the functioning flue as seen in the image labeled Right Liner. Even more black spots as seen in the image titled Top View... but thought them to be soot marks. Maybe they ARE lightening scorch marks.

Good thing I cleared up the mold vs. snow issue, you southern folk were losing quite a bit of sleep!

A BIG issue we have in this part of the country with masonry chimneys that the south does not have (given one is far enough south, that is) concerns freezing temperatures. The slightest bit of moisture in the tiniest crack in the chimney can cause vast amounts of damage to it as it freezes and expands.

Hardly seems to stay warm enough, long enough any more, up here to create mold! Just freeze and crack type stuff.

------------------
Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 21, 2005 08:04 PM            

I was in Minneapolis on Monday- Tues. I'm sure glad it warmed up from -12F to a blistering +5F!!!

When we moved to Philly, my 3 y/o daughter awoke to see cars on a lot covered with snow and she exclaimed, "Look Mommie! Soap!"

We were moving up from SC...

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Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 22, 2005 07:10 AM            

Yeah, ya know your getting acclimated to the cold around here when you reach your hand into the refrigerator to get some milk and the temp in there actually feels warm!

Every year the wife and I swear we are going to move to a warmer climate but here we are still. We've analyzed it and found that Minnesota has 2 very good features that are hard to find in warmer climates; an abundance of good, clean, potable water (which people waste sinfully in this area, I'm ashamed to say) and the fact that the cold kills or repels lots of types of snakes and creepy crawler bugs. Also, the frost factor almost guarantees homes have basements so we HI's don't have to deal with crawl spaces and THAT'S a beautiful thing!

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Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

Ralph Stakely
Member


Posts: 699
From:Fayetteville, Georgia
Registered: Mar 2001

posted December 22, 2005 07:52 PM            

No problems here. Do you thinK?

Click for photo (65214 Bytes)
Click for photo (70433 Bytes)

On top of that, there was no damper. It had rusted out and had been removed. A nice 8 inch hole straight out through the roof. Easy to keep heated and cooled. No drafts or nuttin'.

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Stay safe and play nice.
Ralph

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 22, 2005 08:05 PM            

Ralph, what do you think caused this? Testing ya'lls chimney knowledge...

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Ralph Stakely
Member


Posts: 699
From:Fayetteville, Georgia
Registered: Mar 2001

posted December 23, 2005 10:09 PM            

My guess would be settlement or movement of the entire chimney. As you can see not only are all the liners cracked, but they are also misaligned. The true extent of the damage does not show up in the pictures.
Of course that is just my guess, ( I ain't no chimney eggspert)
This structure was built in early 70's.

Of course, bon fires, no cap, rain, freezing (yes it does get that cold in Ga. 19 degs last night) can add to the problems.

I made sure that the buyer, seller, and both agents knew that this fireplace should not be used for any type fire, until it was repaired. Or completely rebuilt. Any deaths resulting from use in present condition should be considered their responsibility.

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Stay safe and play nice.
Ralph

Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 28, 2005 01:33 PM            

Just received a call from the chimney contractor concerning the damage noted at the beginning of this thread. He cleaned the working flue and ran a camera down into it and the crack(s) run the entire height of the chimney. $6,500 repair bill to replace the liner from the smoke chamber up. Said the cracking was consistent with damage done by a lightening strike. Did the camera inspection with the insurance adjuster right by his side, he said, so there would be no quibbling about it. Didn't say if the insurance would pick up the entire tab or not. Guess I should have charged the client more for the inspection, look what they saved!

A burning question (that will most likely never be answered) is, why didn't the previous home inspector who did the realestate companys "warranty" inspection catch such a glaringly obvious problem or if they did, why did someone opt to ignore it. Hmmm...

I also wonder what the warranty companies response would have been had my clients purchased the home without an inspection, being lured into a false sense of security that the warranty would protect them, and THEN discovered the problem and filed a claim.

------------------
Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 28, 2005 04:22 PM            

Any time you see longitudinal cracks like this, you have to rule out a chimney fire. Due to the hoop stress, the clay flue rips itself apart lengthwise and opens up. Later, when the chimney cools, it closes up to a hairline crack. Every time it gets hot, it can re-open and close, allowing creosote, heat, and moisture into the interstitial spaces of the chimney.

I wonder does that "dummy" flue actually run the length of the chimney or is it just one section at the top? Regardless, filling it with mortar is an unacceptable means of sealing it.

If it indeed was lightning and the cracks extended all the way down to the smoke chamber, how do they know it didn't damage the outer wall of the chimney? I mean, the entire chimney could be split in half. Is it visible inside? Why didn't the lightning damage the smoke chamber, too?

I'd be curious to see some digital captures from the scan and how they ascertained it was lightning. Usually lightning damage is a little more graphic and unilateral. Could be...

Around here, that price is cheap! He has to break out the existing flue tiles, make sure the rest of the chimney is structurally sound, then install a listed liner with proper insulation that is big enough to meet the sizing requirements of this Fp. I wonder how he plans on sealing the base of the liner and if he's going to reuse a throat damper or install a top damper?

The job should include just the liner, less the deductible. Any repairs to the firebox, or exterior that cannot be blamed on this casualty but are a result of wear & tear or lack of maintenance are not covered. For instance, repairing a smoke chamber after a chimney fire might be covered because that is not the normal combustion chamber. However, repointing the firebox is a homeowner maintenance issue and would not be covered, nor would water proofing or flashing repair.

I'd still like to know how they ruled out Ralph's point, too. You can often get an initial casualty or damage which opens the door for subsequent damage such as water or freeze-thaw.
Good thread,
Bob

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Bob Knauff
Member



Posts: 1296
From:MN
Registered: May 2002

posted December 30, 2005 08:56 AM            

Bob H. - "I wonder does that "dummy" flue actually run the length of the chimney or is it just one section at the top? Regardless, filling it with mortar is an unacceptable means of sealing it."

No way of telling the depth of the dummy flue at this time of course but without exception, the concrete fill in the flue is what I see on every chimney of that type. I agree it is a poor job and defies logic in light of the water collection and freeze/thaw problem it creates.

The contractor mentioned he planned on removing the damper, at the throat, and rebuilding from there. The chimney was mounted to an outside wall so the exterior side was visible and not damaged but the portion that abutted the home certainly could be, I would think. No way to tell that either until the flues are removed.

Another problem with the fireplace involved a couple of mortar joints at firebricks in the back face of the firebox where the mortar has pulled away from the end of the bricks and left a hairline gap. I originally wrote those up too and asked the repair guy about them also. He said they most likely were due to the fact that the chimney had no rain cap and rain water has caused the bond to fail since refractory mortar is water soluble. He included that problem in the repair estimate under lightening strike but admitted to me it may not have been.

Bob H. - "Any time you see longitudinal cracks like this, you have to rule out a chimney fire."

So what you are saying is, this type of cracking is due to lightening or structural movement not including excess heating from a chimney fire?

------------------
Bob

Think Safety!

www.BeaconHomeInspections.com

Proudly serving the Twin Cities and areas surrounding Minneapolis and St. Paul in Minnesota

Bob Harper
Member


Posts: 266
From:Drexel Hill, PA
Registered: May 2005

posted December 30, 2005 09:32 AM            

Bob K., yes, there are a lot of complexities to fireplaces and chimneys. That's why it takes Dale 6 days to teach a Basic level course! As you saw in this case, so many of your and our questions cannot be answered directly but must be considered since so much is inaccessible and we didn't watch over the mason's shoulder while he built it.

FYI, NFPA 211 calls for a "medium duty non-water soluble calcium aluminate refractory cement mixture". If they are using this mortar (which no one does) then the mortar solubility would be another issue but you're right, we certainly have to consider that as one portion of the failure here. Keep in mind, such failures are seldom one smoking gun and it is seldom one silver bullet that kills a problem (liner, patch, repair, etc.) With chimneys and their interaction with the house and elements, we have many forces that come into play and we can't always be sure exactly what happened.

While you can get longitudinal cracks from handling damage, lightning, etc., because they can be a hallmark of chimney fires, this must be at least considered and hopefully ruled out. However, since you are relying on testimonial evidence by & large, this is unreliable. Most people don't know they ever had a chimney fire. Also, what about previous owners?

Lots to consider.
Happy New Yr.!