Mostly Cosmetic Repair to Stone Chimney?


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Old 04-17-08, 11:35 PM
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Mostly Cosmetic Repair to Stone Chimney?

Sometime over the past 50 years, a large rock and a couple of smaller ones, above and below the larger stone broke off of the backside of my chimney top. It's an exposed area above the roofline, but not visible from the road.

I'm currently up there redoing my roof and fixing all kinds of things as I go. It makes sense to me that I should repair the chimney before I pull the shingles from that section and certainly before I put down the new, so if you don't mind, I have a couple of questions about repairing this dropped stone and while I'm at it, I should probably make a mostly cosmetic change to the very top.


1) The large stone which fell off was from the base of the exposed top. IOW: It was right at the roofline and it's been sitting up there on the roof, ever since.

Ideally, I'm thinking that I may be able to "glue" the large rock back into place with some kind of mortar, then once it's held in the right position, I could go through my collection of smaller rocks (which may or may not include those which broke free). And, once I've found the "right" smaller rocks, I could fill the area around the larger stone with mortar and embed the smaller stones in it.

Does this sound like the way I should/could proceed, or should I go about it all at once? The reason that I'm thinking about doing it this way is because the big rock goes in at such an angle, I'd need more hands to support it, while trying to fit the smaller stones.

And does anyone have any suggestions about the "glue" and/or the proper bag mortar? Also, I'm not sure at this moment if it effects the mortar choice or maybe the mixture, but I'd like it to be greyer than the "normal" bag of Portland, so that it looks kind of "aged".

This greying isn't quite as important because about a third of my repair will be behind the flashing, but there is an obviously repaired area in one of my stone planters, which you can tell was repaired because unlike the rest, the mortar is white. If at all possible, I'd kind of like this repair to be slightly less obvious to the naked eye from ground level.


2) Also, the whole chimneytop (the flat area at the very top of the chimney) has one corner, where the cement which was smeared over the the top of the stones has broken down into dust. The chimney itself seems structurally sound and I consider this mostly cosmetic, but I'm figuring that I could just trowel some mortar over the "bad" part and perhaps I'd need to smear it all around to sort of blend between the old and the new.

Again, if anyone has any thoughts, suggestions, questions, etc., I'd be grateful for the help.

Oh, and the actual chimney is a square clay pipe running down the middle and the stones are simply laid around the center pipe.

Thanks
 
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Old 04-18-08, 09:06 AM
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Though my word pictures may border on a thousand words, it's become obvious from some of my other questions to these forums that nothing beats an actual photo.

Therefore, the following two pics may help better communicate my questions in the original post.

Thanks again for any and all help. It's much appreciated.



 
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Old 04-18-08, 10:55 AM
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Your issues are more serious than you describe. The chimney crown has deteriorated and needs to be replaced. It has allowed moisture to penetrate behind the stones and with winter freeze/thaw, mortar joints have deteriorated and stones have spalled off the chimney. To do the job properly would require tearing out the stones, replacement, and proper construction of chimney crown. A chimney cap would go a long way toward protecting the chimney crown. The chimney needs to be professionally inspected to determine if there is any moisture damage on the interior of the chimney.

http://www.popularmechanics.com/how_...c/1275246.html


Photo Credit: vonderhaar
 
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Old 04-18-08, 12:05 PM
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Thanks Twelvepole and perhaps freeze/thaw may have contributed to the stone(s) which fell off, but I feel that it most likely only contributed to a problem which had more to do with age. (There's another stone along the roofline that has a visible crack in the mortar and I'd guess that if freeze/thaw has had any effect, it would've been from windblown snow from one of the times it snows more than an inch, every five or six years)

Per your suggestion, I ran a few zips through the "Chimney Safety Institute" which I found linked from another thread and it looks like there's only one certified sweep in my state (about a 150 miles from here) and I don't find any certified inspectors within that same radius, neither through their search or through a Yahoo!. There are a couple of brickmasons in town, a janitorial service who will also sweep and my targeted websearch showed some home inspectors who list chimneys on their website, along with everything else they'll look at, but those that I've found would involve my paying mileage and they're really just home inspectors, not experts.

And, though it may seem like I'm being contrary (which I don't mean to be), but I'm not seeing any cracks underneath the deteriorated crown (except for maybe one shallow hairline) and because we only get about 7-9" of rain over the course of a year and because we've had no measurable precip since November, I really don't think moisture has been a problem. In fact, whenever it snows, it usually disappears within a couple of hours because I'm in a very dry, desert climate.

With all that said, I'm sure that you're right and professionally repairing the chimneytop is probably what's needed because it's old and some of the mortar isn't in the best shape. After all, I'm sure it was probably built by some member of the previous owner's family and it looks like there was a lot of gooping it together to start, but I'm really working on installing shingles and repairing the roof at this time and am mostly asking about cosmetic chimney repair because I'm up there and would rather risk spilling any cement onto the old shingles, than for me to work on it over the new. Not to mention that the loose rock(s) would mostly be behind the 4" flashing that I'll be installing where the chimney meets the roof, so I'll need to repair it, first.

Of course, if it'll make you (or anyone else) feel better, I could take some photos of the flat sides, but there really is just the one other area for future concern along the roof at the other corner and a couple of spots where a silver dollar-sized bit of old mortar has broken-off over the years.

All in all, I've got an 11' square pipe running down the center of a chimney that is 3'x3' at the top and 7' wide at the bottom. The whole thing seems pretty solid to me and actual chimney repair will most likely fall to the next guy because it's not on my list. I'm sure you're correct, in that the part above the roofline could probably be best repaired by being rebuilt, but I'm really just looking for tips about sticking the stone(s)back into place and prettying-up the crown at this time.

Nonetheless, thanks and with the help of your drawings and your response, I certainly have a better handle on the terminology, but unfortunately, I'm really just hoping for a quick fix.
 
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Old 04-18-08, 12:45 PM
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If this is a working chimney, concerns would be the interior where mortar joints could have cracked or spalled. Thus, the importance of the inspection to prevent chimney fires and carbon monoxide.

You can do some reading about stone repairs. Here's some links:

http://www.users.voicenet.com/~tonyspg/point2.htm

http://www.diydata.com/techniques/br...ting_walls.php

http://www.ehow.com/how_115757_fix-c...g-chimney.html

Chimney crown sealer system:


Before


Photo Credit: Home Safe Hearth & Chimney
ChimneySaver Water Repellent System

It's a pity that a chimney professional is not closer. Many not only inspect, but make repairs, and will rebuild tops of chimneys, crowns, and then cap them. Check your yellow pages.
 
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Old 04-18-08, 02:30 PM
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Thanks. I'll definitely give those websites a good going-over tonight.

Otherwise, I haven't seen any loose mortar in the fireplace in the five years that we've been here, but maybe if I open the flue (which has been closed for a couple of years), I'll learn something different. We haven't ever used the fireplace, primarily because somebody sometime installed the thermostat in the same room and because the local janitorial service only added sweeping in the past couple of years and I didn't want to use it until it's given a good clean.

Of course, if you look down the chimney, everything looks fine, but it's a 50+ yr-old house and I didn't want to actually use the chimney until I knew that it's safe. I'm figuring the next people will probably feel the same way, we will be selling the place sometime and I'm thinking that their home inspector will be the one to catch or recommend anything more to be done to the chimney

Thanks again for the links and I'll read through the info this evening. A cursory look made me wonder if there's anything there about "gluing" the loose rock, but I may not have seen it on my quick pass and it did look like there was some info about building one from scratch, so maybe the info can be extrapolated.

Thanks.
 
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Old 04-18-08, 02:42 PM
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Perhaps the following link will be helpful: http://www.stoneyard.com/installthin...ingveneer.html

You have a lot of mortar joints that need to be cleaned out and repointed to keep out moisture. The crown most definitely needs to be properly sealed to keep moisture out from behind stones.
 
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Old 04-18-08, 03:27 PM
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Just call a mason...any mason can build a new cap.

If you want to DIY go to this page, third section is repair and gives full details how to construct a new cap.

I paid to have this done because the cap is too heavy to carry up a ladder. I imagine it is possible to drag the concrete up to the roof and build the form in place. (I don't LIKE ladders!)

http://www.contractorssolutions.com/...n/Chimneys.htm
 
 

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