Att: Masons re: Chimney Crown & Repointing

D107

Edit: 8-3-20 Note that at this point, it has been determined that the chimney flashing was done properly and that the situation calls for a new chimney crown and repointing, with perhaps a wider cap to keep dripping water off chimney.

Three years ago we had closed-cell foam installed in our attic under the roof. All’s been going well, esp. energy savings and comfort. Last week my wife noticed powder (sawdust-sized particles) from the insulation falling from the top of the chimney in one area. See photos. (1924 house)

Had an exterminator out today. Said white powder could be the white caulking outside of roofing flashing. To us it looks and feels like the foam. Said ants usually gravitate towards moisture and rotted wood, and would show some excreta or a few dead ants--none of which were visible. Recommended I get a roofing co or chimney co to check flashing and inspect chimney top from outside. If it's ants, he can come by with a micro-injection guaranteed for 90 days.

After he left I re-inspected and finally found a scout ant coming from the area where chimney meets foam. So I have a roofing company coming to check the flashing. And we'll have a micro-injection in a few days. I would spray it myself in the meantime but perhaps wait for company to come to get them all in once place.

From the photos I can see possible openings from bent copper flashing which was installed in 2012; white caulking could be compromised. Also brick pointing looks a little spotty in a few places. Perhaps water can pool somewhere inside chimney? Hard to say. In ten days ants have dished out probably a few cups of foam so I'm tempted to spray something at them myself just to halt them a bit--afraid of them starting on the attic wood, but perhaps best to wait for the pros so I don't end up inadvertently moving them to another place. I did hear a slight rustling noise the other night, so I'm not surprised it's ants. I've also included a photo from before the foaming took place.

mattmia2

There are lots of places for water to sit on and leak in that chimney on top of that decorative ledge. I would repoint it and consider making a coping that extends from under that plate on top of the chimney all the way to off the edge of that ledge to shed the water away. Especially if you are someplace that freezes, snow is just going to sit on top of that ledge and work its way in to the mortar joints and bricks.

Fred

That flashing was not installed correctly. The sides should lay under the shingle and then lap over the shingle once past the front and back flashing. Step flashing on the sides is even better. The front and back flashing should lap over the top of the shingle. From the looks of that 6th picture, it just looks like the flashing is chaulked to the sides of the chimney with no lap under the side shingles and probably no overlap on the front or back. Also, your 2nd picture shows wood damage from moisture, around the chimney.

Jamie Hall

Agreed. You have water coming in around -- and probably through -- that chimney. The top mortar is shot -- notice the mesh sticking out (shouldn't do that!), so that needs to be redone, then a metal -- preferably copper -- cap over the top and out beyond the decorative course (3rd course down) and then bent down, to shed water beyond the chimney onto the roof.

Then the roof flashing should have been set into the mortar joints between the bricks, not just caulked to them. Caulk is nice, simple, cheap, quick, and doesn't hold up beyond a year or two on brick. And, as has been said, it must continue out onto the shingles to do much good -- and that should be sealed down with quality roofing cement.

And do get someone after the carpenter ants. They can cause considerable havoc in damp or rotten wood.

Zman

Ants, like most all living things need water. Get rid of the water and you will be rid of the ants.

Total

I have used Termidor before , Spray one carpenter ant or where you see them walking , wait a few days , all are dead . One will infect the complete nest . https://www.amazon.com/gp/offer-listing/B0058DGMKG/ref=dp_olp_afts?ie=UTF8&condition=all&qid=1593038387&sr=8-4

HomerJSmith

Ya, carpenter ant are a ****. They can do a lot of damage to a structure, over time. I've had a lot of experience with those critters.

Where ever they're nesting in foam or fibre glass insulation, they do come out to forage. I would put a perimeter around the house of Antrol and spray with ant spray where they're entering the structure. When the Queen dies the nest dies.

They're really not bad, they're natures recyclers. It's an ordered Universe.

Erin, the meaning of a word, in many cases, is determined by the context in which it is used. This especially true in Economics. Words have multiple meanings.
verb (used without object)
****Slang. to complain; gripe; difficulty

We live in a Political Correct age where words have only one meaning and it is usually taken offensively. Ya, I know you probably have a filter.

D107

Thanks for the great replies. It shows me that no matter how much you might trust a contractor--the two chimney guys were very well reputed and one I'd had very good experiences with--we consumers must do our own research. All these twenty two years no one has suggested there was any problem with the way it was. (Top part of Chimney was repointed many years ago.)

@Fred the photo that shows the water damage to the inside wood is showing very old damage from prior owners. We never had water entering there since we've been here--though of course the point is taken that the wood is not in great shape. That we haven't had more prior damage is our good fortune. This flashing--identical to the prior--was redone in 2012 with our tearoff and new roof.

@Jamie Hall Having a roofer come tomorrow to assess. Our roof is 8 years old and we'd expect to get at least another 8 out of it. Seems like best time to totally re-do chimney crown, coping, flashing would be at that time, but then I don't see any way of avoiding redoing the roof flashing--that would seem a minimum.

@Jamie Hall So the existing cap-grill which covers both the fireplace and gas flue liners does not serve well? (photos 5-6)

Part of the problem is finding knowledgeable contractors with the kind of standards prevalent on the Wall. What gauge and kind of copper should the flashing be? I'd spend the money required for a complete re-do if I could have faith in the installer.

Could a copper sheet be molded over the existing crown?

I have been looking online but have not yet found good examples of proper chimney top setups. If anyone has any, feel free to upoad.

Exterminator will be scheduling a micro-injection in a few days to take care of existing infestation. We had super heavy rains a few weeks ago which probably caused this issue. But it's been dry for two weeks. My concern is that with all that foam there, ants won't need the water or rotted wood to attract them--they've found the mother lode. Anyway, setting up good perimeter and barriers and even some natural deterrents should help.

mattmia2

You need a good mason, not a roofer.

mattmia2

That counter flashing at the roof may have a lip bent in to the top and be set in to a groove cut with a diamond saw which isn't great but is ok, it might not just be stuck on with caulk. I would much rather see it stepped in to the joints in the bricks.

Your main problem is that moisture is entering between the bricks in the chimney and leaking in that way. A mason either needs to repoint and replace the spawling bricks or tear it down to about the roof line rebuild it. Rebuilding might be easier in this case. They should rework the counter flashing and either make a top cap out of metal that extends down to that top course that forms a ledge or at least make a sloped surface out of mortar on top of it to shed the water off. A good mason can work the metal in to the brick a lot better than a roofer would be able to.

ChrisJ

mattmia2 said:

You need a good mason, not a roofer.

Oddly enough when I had issues with my B Vent, Duravent told me I needed a roofer not a chimney guy.

I still haven't figured out which is correct.

D107

The company that's coming tomorrow is GC, so if I hire them I'll have to make sure they have a good mason in their ranks. Seems like primary leaking is happening with flashing and pointing.

D107

And while we're at it, perhaps this stack vent should be better flashed than it is? Appears to me that the weak point would be the mastic cement where the pipe meets the rubber boot.

mattmia2

That flashing shouldn't need roof cement, it should be a synthetic rubber boot that seals to the pipe.

I'm not sure a chimney company is really the right company either. You mostly need someone who specializes in bricklaying and knows what kind of brick that is and if it can use modern portland cement mortar or if they need a softer mix and how to make it shed water properly and all that sort of thing. I would ask for pictures of their other work where they had to work on historic brick like that. It is clear from those pictures moisture has caused a lot of deterioration and if they don't remove and replace the deteriorated mortar and bricks, moisture will quickly get back in and deteriorate the new work.

D107

@mattmia2 Thanks, I'm not sure there really is mastic cement on that boot--hard to tell from the distance. But apparently no additional flashing over the boot and shingles is required.
Good points on the masonry subtleties--yes wrong mortar and more problems down the road.

Jamie Hall

Those existing cap covers (photos 5 and 6) are OK -- so far as they go. They don't go far enough. The problem -- clearly visible in those photos -- is that the mortar on the rest of the top of the chimney is severely deteriorated. That is going to let moisture into the top of the chimney bricks (older bricks are not water proof, by the way -- water resistant, yes, and on a vertical wall that's all you need, but they will let water in on the top of a horizontal surface). You really need a copper cap, under those covers, extending out horizontally in all directions beyond that projecting row of bricks two courses down, so that any water which falls on top of the chimney drips down beyond that projecting course -- otherwise the ledge on top of that course will collect water, which well get into the chimney, and so on.

I agree. Good masons are really hard to find these days. And they don't come cheap.

Whatever else you do, please don't let some bright child spray or paint sealant on the bricks.

D107

@Jamie Hall Any chance that crown has asbestos? That would complicate things nicely....

Jamie Hall

Anything's possible -- but I'd be rather surprised. It's not insulation, after all -- it's mortar.

mattmia2

It is a lot more likely to be in the old roof cement or caulk. Most roof cement before sometime in the 90's contained some asbestos.

Jamie Hall

mattmia2 said:

It is a lot more likely to be in the old roof cement or caulk. Most roof cement before sometime in the 90's contained some asbestos.

I think @D107 is concerned about the white stuff capping the chimney, seen outside the metal covers with the reinforcing mesh peaking out. Not roof cement -- I've never seen roofing cement that was white -- but I suppose someone could have spread caulk... with reinforcing in it...

Anything's possible. And, of course, if one is concerned, one could have it tested and, if it does contain asbestos, professionally remediated before doing anything further to disturb it.

ChrisJ

Jamie Hall said:

mattmia2 said:

It is a lot more likely to be in the old roof cement or caulk. Most roof cement before sometime in the 90's contained some asbestos.

I think @D107 is concerned about the white stuff capping the chimney, seen outside the metal covers with the reinforcing mesh peaking out. Not roof cement -- I've never seen roofing cement that was white -- but I suppose someone could have spread caulk... with reinforcing in it...

Anything's possible. And, of course, if one is concerned, one could have it tested and, if it does contain asbestos, professionally remediated before doing anything further to disturb it.

My dad had a bucket of white roof cement.
It was just like the typical Karnak only in white.

D107

This diagram I've cobbled together from two is the best I've found that illustrates the proper setup. If the chimney ends up being rebuilt, I'm hoping that a skilled mason could somehow knock down the top part of the chimney without destroying the fireplace 7x11 terracotta liner.

mattmia2

Have you looked to see if the terra cotta liner goes all the way to the fireplace and wasn't just added the last time the chimney was rebuilt from the roofline or so? It wasn't particularly common to line chimneys in the 20's.

My comment about the roof cement and caulk was more that virtually every older roof has some asbestos in it that is embedded in tar and more or less non-friable. Like others said, the mortar is unlikely to contain asbestos but sometimes it was added.

D107

@mattmia2 I doubt that this 1924 home's chimney was ever rebuilt, but good point if there is a liner on the fireplace side--I only assumed there was. Quite sure there is one on the boiler side, but that's less important since there's now a stainless steel liner inside. Will have to check this out.

D107

@mattmia2 Just took a look up the fireplace, and yes indeed there is what looks like two? ft terracotta sections of liner starting right above where the wide part of the fireplace narrows down. couldn't see how far it goes up but can't see why it wouldn't go up all the way. So I'd have to assume any mason could be careful enough to remove only the liner above the roofline if they were rebuilding and then reline that new two feet of chimney. All while propping up the heatlng liner.

I'm wondering if there's a way to use metal or a cement mold instead of bricks as a chimney above the roofline? Or just cover the existing brick chimney above the roofline with copper flashing all the way up and then remove the crown and create a new sloping coping, and bigger cap?

Jamie Hall

That diagram will certainly work -- although one could make the brickwork a little more decorative (like flaring out for the top course or two) if one liked. The chimneys on Cedric's house are all two thicknesses of brick, plus a liner -- but there are other ways to do it.

And a competent mason should be able to go down as far as needed to reach sound mortar and build back up from there. No problem.

Bob Harper

You really need a Level II inspection. Guessing is useless. This will determine the suitability of use and guide repairs. No, you are not allowed to reline with terra cotta. The masonry must be carried up after the tiles are set. The tiles are rarely set correctly on one another and never with the proper mortar much less laid properly. The drawing is pretty good. The concrete 'cap' or crown must be reinforced with 1/2" hardware cloth per ASTM C 1283 with a 10degree slope. To minimize the water intrusion I would have a custom stainless steel outside mount rain cap installed over the cast crown. The exterior should be pointed with lime mortar because it breathes, unlike Ordinary Portland Cement (OPC) based mortars that capture moisture. The counterflashing should be 'let' into a reglet or channel in a mortar joint or cut the pitch of the roof and secured with lime mortar- no nails and definitely no caulk. Caulk ALWAYS fails. Treat the entire exterior with a water repellent that is 100% vapor permeable such as ChimneySaver. Never silicone-based sealants such as Thompsons that ruin masonry. You have combustibles touching the chimney so to meet this zero clearance condition you need to reline both flues with listed liners. The fireplace flue will have to be sized to the opening of the firebox. The smoke chamber must be parged with special insulating mortar. The liner will require the special insulation to meet the UL listing for a zero clearance. The heater liner does not require insulation but it won't hurt. There should be a nominal 4" wythe wall between flues. Flue tiles must extend btw 2-4" above the crown per code and have the resilient seal to the crown. Yes, the crown must have a 2" overhang with a drip edge 1.5" from the face of the chimney. Get a pro in there with the camera so you know what you're dealing with.

D107

@Bob Harper Thanks. you said:
"No, you are not allowed to reline with terra cotta. The masonry must be carried up after the tiles are set. The tiles are rarely set correctly on one another and never with the proper mortar much less laid properly."
My layman understanding has been that 'tiles' are flue tiles within the brick, and those tiles are clay aka terracotta. So if the tiles being set are not clay, what are they?

I would have a custom stainless steel outside mount rain cap installed over the cast crown.
Not sure if you saw some of the other photos that show the rain cap that covers both flues. I had a company come out Friday to inspect. (They sub out to a special masonry guy for work like this if they get the job.) The guy who looked at the angle from the top of the existing cap said the rain will not fall on the chimney.

And these being old bricks, yes lime mortar, and maybe a careful powerwash to get all the black grime off before the Chimney Saver?

The company said that a groove had been cut into the masonry for the flashing edge. So you're saying that caulk should be removed and maybe a wider groove ground in to accept lime mortar?

Company also said they would weld the bent corners of the flashing that possibly may allow water entry.

Where do combustibles touch the chimney?

The new 5" boiler liner is listed stainless steel 316L and has a tee cap on the bottom and is sized properly for the Peerless MI-03 . The 1924 fire flue is grandfathered and we've had it inspected a few times over the years--no buildup of creosote since it gets very little use. The top damper was installed twenty years ago when some repointing was done. We likely have at least the 4" gap between the flues.

As I've followed the Wall for years, I know you have deep knowledge of these things. The state of the art here though is very limited. After serious research, I had the best two local chimney companies working on my chimney the last two decades and they made no other recommendations. I don't think I can trust a full rebuild to any company I know of in the area.

I'm awaiting this third company's written proposal, but I'm pretty sure they will recommend:
1- Repointing all brick--with lime mortar.
2-Welding copper flashing corners
3-Re-caulking or mortaring the flashing groove into chimney

I will also ask them to inspect under the coping around the boiler liner to see if there are any gaps in the caulking below it that might let in water or bugs.

I would also like to see a new crown or coping. I am also not clear if the current flashing has the required counterflashing over shingle where it should. I'm awaiting the photos that the contractor took.

If it's of any use I'm attaching photos I found of the last roof install and chimney re-flashing from 2012. I can say that for 22 years we never had water entry into the attic around the chimney as I used to check quite often. Apparently, based on evidence of insects, now that the foam is in our luck has run out.

The Steam Whisperer

That spray foam should definitely be removed from around the chimney... that's usually a fire safety issue and code violation.. An air space is required between flammable materials and a chimney. I would get the installing company back out to correct thier installation.

D107

@The Steam Whisperer (Formerly Boilerpro) ah that's what Bob Harper meant. I'll have to check the applicable codes (NYS). I recall that they put special red fireproof caulk on a few sides of the chimney where it meets the foam--why not ALL sides I don't know. But they were also required to paint a coating called DC315 on the complete foam surface to obviate the need for a sheetrock covering. (Made by International Fireproof Technology Inc.) I know that was a code issue we dealt with.

Jamie Hall

Whoa whoa! Wait a minute here. If that's lime mortar and old brick, do not power wash the chimney and do not put a sealant, such as Chimney Saver, on it. Those bricks and that mortar are meant to breathe, and their life will be short and nasty if you try to seal them -- and the power washing will destroy the outside of the bricks, never mind the mortar.

D107

@Jamie Hall thanks--though I thought a gentle low-pressure wash might be possible. I guess they could be hand-scrubbed with a bristle brush and some mild dish detergent or muriatic acid? etc. as long as they protect the shingles when they're up there--which they should be doing anyway. (Brick was installed 1924, which means brick itself could be ten years older, which would seem to be the old-school bricks that require lime-mortar.) Friday the contractor reported that prior minor re-pointing done who knows when was done with glue(!)

Jamie Hall

Scrub them with a bristle brush (not wire -- coarse natural. You'll use it up, but it will work) and a mild detergent of some kind -- not muriatic acid which will attack the mortar. Then just hose them off. You'll not get all the white off -- that's part of the character.

Glue, eh? Well... sigh.

Bob Harper

Terra cotta is clay tile. Must meet ASTM C-315. Even if the tiles are still intact I'll bet you a steak dinner the joints are not. The multi-flue cap shown does NOT protect the entire top of the chimney. For one, the chimney corbels in to the crown instead of corbelling out forming a drip edge. You said no signs of water damage but lead off complaining of efflorescence, which is water leaching salts of the the masonry. The foam is combustible. It does not pass ASTM E-136 even with a flame retardant coating. Interior chimneys require a 2" clearance to combustibles. Also, prove that the framing is not touching the chimney. If the chimney was laid in lime mortar, it will fizz up when sprayed with vinegar. Yes, never wash it with acid. The acid will continue converting the lime into salt for years. ChimneySaver breathes. It is the ONLY water repellent I know of suitable for use with lime mortar. The BIA has stated if a coating is not 100 % vapor permeable, don't apply it. Until you have a proper level II your guys are guessing. Just saying. Glad to hear about the SS liner to the heater. That crown was very poorly constructed and will hold water. That RMR top damper is somewhat restrictive. As long as the copper flashing shown is counterflashing separate from the base step flashing it might be ok. One piece flashing is not. You must use lime mortar for old soft fired bricks. Even with hard fired SW grade bricks it facilitates drying over OPC mortars.

ChrisJ

I don't think I've ever been in a house where the brick chimney didn't touch framing. Is 2" to combustibles from a brick chimney a recent thing?

D107

@Bob Harper My choice of 'white powder' to describe the foam particles was unfortunate. Exterminator thought it might be caulking from the copper flashing but to us it more clearly seems like the closed-cell foam ground up by carpenter ants or driller bees and is dropping through the slight space between foam and chimney. It is not efflorescence but is the consistency and particle size of sawdust. There may be signs of efflorescence on the chimney itself in some of the photos and some wood rot from many years ago. Yours and the posts of others have been super-helpful and informative. Chimney science doesn't get enough attention.

D107

Ok exterminator took care --temporarily--of the existing carpenter ants.

Contractor sent a guy out to take photos. I've received a proposal for proper re-flashing and removing some shingles around chimney to see if any wood needs replacing. Rubber ice and water shield over sheathing. I await report from their mason.

You can see the flashing was riveted and most likely was not counterflashed properly which they would do with 16lb copper. They would solder/weld vertical edges. They would insert edge into masonry and use silicone caulk, not latex caulk; claim that mortar will crack.(?)

They do say once counterflashed they would nail to go through copper and shingles. ? This gets tricky for me to understand since on one hand you try to avoid nailing through copper, but if your layers are, in order, sheathing, rubber ice/water shield, copper flashing, shingle, copper counterflashing, then perhaps that final copper layer could be fastened with roof cement, but wouldn't you have to nail the shingle below it down--which would by definition go through the first layer of copper flashing?

They are consulting with their mason on the re-pointing, crown, coping, etc and get back to me by Monday. To my untrained eye, it looks like except for some crappy old repointing with caulk and clear silicone?, the bricks don't appear to be spalling from portland mortar--so maybe it was never repointed from the original construction.

What annoys me is that two chimney companies never sought to point out the brick and flashing deficiencies here. Did they hope to get the call when it started leaking?

First two photos are of the corner near which the carpenter ants were discovered underneath; however at least one other corner seems worse, but water can easily move in surprising ways, and aside from the flashing and pointing, that deteriorating cop crown can admit water all by itself.

mattmia2

I see a couple bricks that are spawling but not a whole lot. that is more likely from the water that is leaking inside from the top. It may have been rebuilt one or more times since the 20's especially given the different brick above where it is corbeled out.

The Steam Whisperer

You've discovered one of the big disadvantages of foam insulation, if water gets in,it can't really get out easily and rot occurs. That's why I don't recommend its use unless is is part of a system that allows easy replacement of whole components... such as modular construction in general, especially in high rises.

D107

@mattmia2 @Bob Harper Ok so I now received the second proposal and I'm just disappointed with both.

1-First company--more of a roofing-siding-pavement company for their outside work. Their proposal just included re-flashing --and welding corners--and stripping back shingles around chimney to replace any rotted wood. No level 2 inspection, repointing or crown rebuild. They are waiting for their mason sub to take a look to see about any brickwork. They felt flashing was not counterflashed. They had said the cap was large enough to prevent rain from dripping onto chimney brick but during a rainstorm it was easy to see water dripping off the cap right onto the corbelled bricks that stuck out more.

2-Chimney company--lot of great reviews-- would re-point and add new sloping crown, but no coping with a 2 inch overhang--they said that kind would be too heavy and might crack my chimney. Never heard of such a thing.

They believe the flashing IS counterflashed--see photos below. I tend to agree and think on the sides I see a second layer of copper beneath. No level 2 inspection to look at the inside of the fire flue. Not a word on specific materials used: what kind of mortar, chimney spray-on waterproofing. When I suggested a soft lime mortar, they said it's not the kind of mortar as much as re-pointing the proper way; said they grind out 1/4". One thing I think they pointed out correctly was that the current white-ish crown is actually black roofing cement painted over white. They would leave the existing cap--said it could never be made large enough. (?)

I have observed that around here in Westchester and my mother's old house on LI, most crowns do not have overhangs, are just sloped concrete where the water drips right off the top--which depending on other factors might last 5-10 years.

I don't see anything like the standards that you see on the Wall or even in many basic home improvement books about masonry, chimneys etc.

Note in the third photo showing the cap, it appears the fireplace damper is partially open--maybe it's an optical illusion. I checked the chain on the fireplace which is as tight as can be. That could certainly let water in.

My understanding is that type 'N' Portland mortar mix would be the type to use for my old bricks.

mattmia2

I think there definitely is step flashing and counter flashing. It could be set in to the masonry on the chimney better. It could be leaking where it is let in to the chimney and is caulked but probably isn't the majority of your leak. It appears there are many layers of many things on the crown.