# Copper flashing on irregular Rock Chimney



## oggy bleacher (May 3, 2011)

I'm looking for advice on how to attach copper flashing to an irregular rock 'historic' chimney. The "client" wants copper flashing in a channel that I have chipped into the mortar. The ice and water guard is the second line of defense but I can't get it to stick to the rock. Maybe I will use asphalt in a tube unless there is better advice. After I get the water guard to stick to the chimney I will seal it further with asphalt or silicone. Then it will be time to step copper flashing up the angles of the chimney and under one cedar shake after another. The chimney isn't square to the pitch of the roof so it's basically two valleys going up the chimney. 

Has anyone chipped out a channel in mortar between irregular rocks in a chimney and then use mortared to secure it in place? The hard part is the irregular nature of the rock surface means a 3/4'' depth channel in one area is pushed out so the copper lip doesn't fit into the channel in another area that is further back. It's not brick so the mortar channel is neither flat, nor level, nor on the same plane as the face of the chimney. You can see the channel that I've chipped out in the photos. The plan is to overlap the steps of flashing and then fill the vertical voids while shedding water with the cedar shakes.

I'm looking for a photo of what the end result might look like or advice on what adhesive to use.


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## carpdad (Oct 11, 2010)

I'll be blunt. To explain but not in a kind mood and to preface, sorry.:smile:
1. What mean by historic? Historic society or such protected project or historic in the owner's eye? 



2. I'm jumping the gun but I don't think you know what you're doing.


Ice barrier is not the LAST line of defense. It is insurance only, and the defense MUST be the flashing. Ice barrier WILL NOT stick to the stone and stay. It wasn't made for such a job. Any glue you try to use will compromise the glue on it already. May chemically reject eachother.


That chimney, I think, was a mistake to begin and you're trying to go along with the mistake. That is your mistake. The chimney joints also are falling apart. Copper may last a long time, but not that chimney. It needs to be rejointed but the stones may fall apart during that job.



Copper is not soft enough to beat into a crevice. It will split first. And the bends you made is not for small chimney joints. Even lead will not work as such. It needs to be bent, then maybe beaten into gentler curves, but I think what you have to do is grind new joints where it doesn't exist so you can fit the step flashings. Steps don't have to be regular shapes.


As for step flashings, you have to remove more shingles so you can use the steps.


Corner flashing can't be cut in the corner. Search for chimney flashing images.


I'm including only photo I could find. I used words "stone chimney flashing", but only one. The photo shows, not clearly, but you can see how irregular they are. Even then, the chimney builder left relatively straight line for the bottom courses.


Talk to the house owner. That chimney needs a lot of work and money. Not sure if you can do it with what you know now. Another thing that may help is probably a new chimney cap to shed water and protect the joints. In NJ with freezing weather, that chimney will not have survived.


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## carpdad (Oct 11, 2010)

Sorry. The photo.


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## PatChap (Nov 17, 2012)

Is that chimney stone a veneer or structural? If it's a veneer, you need to get the flashing behind it. 
Those chimneys are leak factories.


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## ClarenceBauer (Mar 4, 2005)

I have worked on many Historical structurer that were built dating back to 1803 / 1860 & most flashing on Stone , Marble & other type of materials including brick & the flashing used was lead sheet material. A reglet was cut into the surface to be flashed the sheet flashing was than placed into the reglet & Lead wedges were used to hold the lead in place by pounding the wedge into the reglet where the lead sheeting was.The lead flashing was contoured to the shape of the material that it was applied over & the seams were folded over & hammered together or soldered. I have not tried to purchase lead sheet material in the past 4 years but the last Historical building I work on had very large chimneys & the materials used were brick & Slate & we used Lead Sheet material for the flashing to match the existing. The project was the Richmond Plantation, in Cordesville SC.


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## ClarenceBauer (Mar 4, 2005)

https://south-carolina-plantations.com/berkeley/i/richmond/richmond-plantation-rear.jpg

These are the chimneys that were restored.
I should have advised the OP that the mortar joints need to be raked out I would say about 1 1/2 inches deep than repointed with a matching mortar to the original mortar. After repointing water proof with a high quality clear water proofing.


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## oggy bleacher (May 3, 2011)

This is on a federally owned, registered historic landmark structure so it's a juggling act of preserving questionable 1930s construction methods while trying to mitigate decay. Why I'm involved with no experience with copper chimney flashing on stone chimney is a head-shaker, but that's life.

the stone is structural so the concrete chimney ends in steps about 2 inches above the roof line. There was no original flashing at that step and it made more sense to me to add the copper flashing at that spot, below the stone, but it's not the approved solution at this time. The stone is laid on the steps. in some places there is no mortar joint as the two stones meet.

The cedar shakes are coming up to allow for overlap.


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## ClarenceBauer (Mar 4, 2005)

Ok now what you need to do is research the Preservation Briefs & look at Brief 16 thru 19 they will give you some help hints on wooden roofing. These Brief are put out by the U.S. Department of Interior , National Park Service Preservation Assistance Division, Technical Preservation Services. Any National park service in your area will help you to get all the info on authorized repair materials that are appropriate for that period of time. They can also advise you on who to contact for flashing methods on Historical buildings. Ask the park service what contractors / Firms that they use most are willing to help answer most questions with any charge. Also check with your State archives they will work with you & help find correct method for flashing & water proofing.


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## carpdad (Oct 11, 2010)

Is that also a valley behind the chimney in photo 1? Generally tricky and more than a few posts in the forum about them. Search the forum also. I'd pick a spot where the stone are largest and if you can, cover the smallest stones, and grind a 3/4 deep x 1/4 wide groove. If the job does not call for repointing the stones, at least grind out the joints about an inch or so above the flashing and leave a fresh joints.


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## oggy bleacher (May 3, 2011)

thanks clarence. I'll check out the DOI pres. documents. This is 'skills learning' because those in charge think it would be more cost effective to train a plumber to do roof flashing than to pay a contractor roofer. I can see their point but I'm learning the hard way with winter right around the corner.

yes, there is a valley on the opposite side and the chimney is crooked on the roof itself so it points down the slope. So every piece of flashing has a compound angle up the slope with a semi-flat channel that I chiseled/grinded out today.\

I'm curious about soldering the copper seams while they are vertically in place. Is there a trick to that?


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## carpdad (Oct 11, 2010)

Youtube and many other videos. They use solder bars so a lot of it can fill the gaps in using sheets instead of tight fittings used in plumbing.
I've also seen auto body repairs using solder bars. I never did works like these, and I envy your opportunity.:smile:
I think though, soldering is done on the ground after the pieces are cut and dry fitted. Probably less chance of burning something else and you can do your job grounded and with patience. Also you probably don't want the solder dribbling everywhere. Also the pieces has to look good from the ground, not at the roofer's pov, so the flashings don't have to fit tight to the work. Even if the sheets are floating away from the chimney. Use copper nails also. But the bends need to look fairly sharp and square.
Parts of the flashing, esp on the roof surface, must be wide enough, esp to protect from wind driven rain. The video samples, take note, may be going over tighter jointed roofing materials.


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## carpdad (Oct 11, 2010)

https://www.youtube.com/channel/UCJHLqwsRD4NEXzvNkY4Gm-A


Not a copper worker but many videos dealing with the kinds of work you must learn.
Also search for how to roof with cedar shakes. Roofing is not just about flashing and roofing separated. One material calls for another kind of related flashings, etc.
Since you are already in trade, lot of this will make sense just from your working with hands.


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## ClarenceBauer (Mar 4, 2005)

https://www.nps.gov/tps/how-to-pres...ion-briefs/19Preserve-Brief-WoodenShingle.pdf

This may help you get started as related to the wood shingles.
To get more go to this site " Preservation Brief " & click print down load docs.


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## carpdad (Oct 11, 2010)

My mistake but I was posting as if the step flashings are the final part. The roofer in this video is from UK and he calls them soakers and step flashing as the final cover. In US I've heard counter-flashing and skirts. So your step flashing pieces don't have to be let into the stone joints. Just leave them flat against the stones. Then you can make the counter flashing in larger pieces. If the stones really don't look good for cutting, maybe you can use eternabond tape. Their primer may help with giving you the surface you need for the tape. So the step flashings > counter flashing > tape. This tape also comes in copper surface.


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## ClarenceBauer (Mar 4, 2005)

Note these KEY words " Federally Owned " , " Registered Historical Landmark Structure "

Based on the above words I would highly recommend that all work be done using all the Historical guide lines & have all materials to be used submitted & be approved in writting before being installed also keep good document of the installation methods. If there are not written specifications for the work to be completed you should stop work & ask for specs. & details for repairs. Who issued the order for the repairs & under what guide lines ? Just a written work order could cause a lot of problems.

I have worked on well over 65 buildings that are on the National Historical Register List & believe me there could be a lot of people involved it repairs on any building on this list.


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## carpdad (Oct 11, 2010)

Not to argue, but is it chicken or the egg?
Beauracracy certainly is serious but looks like this is a kind of situation where a person must first taste which way the wind is blowing.:smile::smile:


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## carpdad (Oct 11, 2010)

OP, sorry if I'm laughing too much. I am imagining myself sitting up there with a finger in air. Been there done that under a dark cloud and hind sight is funny.:smile:


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## ClarenceBauer (Mar 4, 2005)

A DIY forum is not the best place to seek advice for repairs on Historical buildings it's not a DIY project. You are getting paid to do it correct with proper materials. I can tell you what material I would use BUT it does not make it the correct material that would be excepted on this building.
Some of the best places to get advice is from Conservators , Architects that specialize in Historical buildings & Preservation Engineers.
Most of the above will give advice freely on what you should do but will not give it to you in writting unless they get paid for the written advice with types of materials to be used.
On the Briefs check the last page under ACKNOWLEDGEMENTS see if you can contact any of those people ( if still living ) they are glad to help. Also check Selected reading on last page.


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## oggy bleacher (May 3, 2011)

There's room for a volunteer or two on the roof if anyone is interested.


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## ClarenceBauer (Mar 4, 2005)

oggy bleacher said:


> There's room for a volunteer or two on the roof if anyone is interested.


You are thinking is on the right track.

Start asking questions in places like The Texas Historical Commission & Technical Schools in your State also check for trade schools that have classes on Historical Restoration.
I don't know what field you work in but if you are interested restoration repairs of Historical rebuilds there is a demand for trades that have the knowledge on restoring building components back to the original using matching materials. If you are doing the work & not working for a contractor by the hour the pay is fantastic. I had a man that used to work for me start his own small restoration business & he came to me to go over his plan & estimate to complete the work his figures were $ 6ooo I ask if he could start & complete the work for that price he assured me that he could we went over his plan I recommended that he submit a cost estimate of $ 10 which he did & he got the job This was for one room 15 feet of plaster Cornish lath plaster & 111 Sq.Yds. of plaster to match the existing plaster.
His real cost to complete I estimated to be $7,750.00 this number includes all taxes , permits , insurance & materials & his markup of $3,000.00 so he makes $ 2,250.00 above actual cost. I used this method for many years & worked on many high profile buildings. Start your own business &make good money.


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## oggy bleacher (May 3, 2011)

I've got my eye on the lead and asbestos abatement market in some cool mining towns that have an abundance of both. I've got certs in lead removal and can easily get one in asbestos...it's methodical and unavoidable if people want to follow the law. There's money to be made removing asbestos siding/roofs.

For some reason this building with the chimney has an 8 figure $ renovation planned that doesn't include the chimney flashing. Or maybe it does and I'm being given an opportunity to learn a skill on a chimney scheduled to be rebuilt so everything I do will be torn down in a year. Those decisions are above my pay grade. 

We made some progress but the finesse of different channel depths and heights and how to shim/wedge the lip into the channel so it stays long enough to nail down...it's frustrating. Of course the brake is two stories below us. But after seeing that copper soldering video we're going to solder after one side of it is in place. It seems like we will have to mortar the channel before we solder it or else we will not be able to mortar in the 2'' overlap.


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## carpdad (Oct 11, 2010)

One thing, you don't have to worry about the approaching winter. It also looks like the chimney could use a cricket, where the tool belt is.
IF the chimney gets rebuilt, do you have to save the rocks?:smile: Mike Haduck is a mason in PA. He's got a youtube site. Ask him. If anybody, he does appreciate history. There is also national or maybe local mason chapters. They may be interested if only to show off.:smile:


BTW, I'm just guessing but is it possible to spot solder the flashing? Like the auto body repairs? Top will have to be loosened. Then when the plates are relatively flat to eachother, finish the soldering. Have a fire extinguisher handy and maybe a helper watching from inside the attic. Make sure there's nothing that can easily catch fire, any insulation, bird nest, etc. Maybe wet the shakes. May need a lot of heating since the stones are like a heat sink. Don't burn the copper.


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## ron45 (Feb 25, 2014)

oggy bleacher said:


> I've got my eye on the lead and asbestos abatement market in some cool mining towns that have an abundance of both. I've got certs in lead removal and can easily get one in asbestos...it's methodical and unavoidable if people want to follow the law. There's money to be made removing asbestos siding/roofs.
> 
> For some reason this building with the chimney has an 8 figure $ renovation planned that doesn't include the chimney flashing. Or maybe it does and I'm being given an opportunity to learn a skill on a chimney scheduled to be rebuilt so everything I do will be torn down in a year. Those decisions are above my pay grade.
> 
> We made some progress but the finesse of different channel depths and heights and how to shim/wedge the lip into the channel so it stays long enough to nail down...it's frustrating. Of course the brake is two stories below us. But after seeing that copper soldering video we're going to solder after one side of it is in place. It seems like we will have to mortar the channel before we solder it or else we will not be able to mortar in the 2'' overlap.


OMG!

You should have cut a straight groove in the chimney, parallel to the roof.


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## ron45 (Feb 25, 2014)

And.


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## oggy bleacher (May 3, 2011)

thanks for the advice but the rock can not be cut on this property. it's irregular stone and the flashing must follow the mortar joint. life would be easy if every chimney was brick. This is kind of like a living museum where no crickets were built and stone was used as the structure of the chimney so nothing can be changed. It's the difference between renovation and preservation. IF the chimney gets rebuilt we actually have to number the rocks and put them back in the exact place they came from.


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## ClarenceBauer (Mar 4, 2005)

Keep going in the direction of preservation that is where the money is learn all you can about it.
Yes I have worked on buildings where the coping stones had to be numbered & reinstalled in the same order.
Check into what training class's are offered for Preservation & attend all that you can & put that info to work for you.
You will be surprised at the amount of work you will be awarded.


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## oggy bleacher (May 3, 2011)

I'm only missing one tricky corner piece now. The question I have is how will mortar adhere to copper? And should I sweat the seams before the mortar or after?


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## carpdad (Oct 11, 2010)

I would solder every joint. Although photo 2 step flashings look like overlaps may be enough. I'd solder first then bend/beat the lips into the chimney a bit more, hold it in with a wedge or nail then caulk with mortar, both horizontal and vertical. Mortar will not stay stuck to the metal. If hairline crack opens, that is part of the material life.


Photo 1, I'd first solder every joint and mortar the joints. Then fit a second sheet overlapping the flat side of the step flashing that covers the valley floor and bent over the ridge. Again soldering all joints. Tricky valley is best covered with wide, seamless cover, esp because the water flows down and sideways there and there's not enough of slope or clear direction for water to drain away harmlessly. I'm in NJ and snow melt actually backing up against gravity is a factor, but even there, I'd want no seams in a corner as such. If overlaps will do, think about the overlaps and how the water will flow. Don't assume your first impression is good enough. That corner, if overlapping only, I'd have cut the steps wide enough to cover the valley and bend over the ridge. Overlaps would have been minimum 6" with a bead or two of osi quad caulk under the overlaps against any capillary leaks.


I know my talking is hindsight and it looks like you're doing very well. Again, make sure you're certain nothing under there can catch a flame. Wood can scorch. I don't know but when you solder the flashing touching the shakes, can you slip fire retardant cloth under? Plumbers use them.


You could practice on the ground with some models. A ply or 2x corner frame with vertical copper pieces and try soldering. Watch the videos. Do you heat the joint or just the top piece, etc.? I'm sure flux is involved.


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## carpdad (Oct 11, 2010)

In the spirit of vicarious learning.:smile:
In this video, this guy is using a direct flame on the copper. But he seems to be burning the whole thing. You can see that the copper isn't really flowing while the flux and copper may be on the point of burning. As a plumber, you know it.


Every other soldering technique seems to be using a metal tip to heat the joint.


Can't find now but saw another video where the worker says that he may have to change to acytylene torch when working in colder weather or windy conditions. Some show electric soldering gun, but again, it may not get hot enough depending on the conditions.


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## oggy bleacher (May 3, 2011)

we did add a 20''x 6 ft piece of copper valley flashing in that left side in photo 1 but I don't have a photo yet. It's a slope that is unique to that area and now there is valley flashing over water guard that abuts the step flashing crease. Then shakes over the valley flashing.

we plan to practice soldering on some seams this week.


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## oggy bleacher (May 3, 2011)

Making progress using basic acid core solder and a propane flame.


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## carpdad (Oct 11, 2010)

Lead free solder?:smile:
Photo 4. Overlap over stone. That will need some caulk. Tape the stone and copper and push the caulk in. Same with horizontal joints because there is no space for mortar. I guess you can tape, push caulk in, then mortar over it? Leave a slope to the copper's edge. Even if it's a historic, can you cheat? As such, I don't think the mortar joint will work. Instead of a joint in a confined space, that joint is lying on the copper shelf and on stone. I think it will end up cracking. Can you use epoxy? Epoxy would have better chance sticking to copper and stone. Before epoxy dries, dust the surface with mortar powder.


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## oggy bleacher (May 3, 2011)

some more progress. the next step is the mortar. we are waiting for historically accurate sand.


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## carpdad (Oct 11, 2010)

What for? Looks like quikcret mortar to me.:smile::smile:


BTW, that was a joke. But if your plan is actually id-ing the original sand, etc, you may want to suggest sand/lime mix that is supposed to be bit more flexible. I don't know much more than that but flexible may be the factor with those stones. Sand probably would have been local.


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