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Discussion Starter #101
Difficult to really know what is occurring there. From the video it looks like that piece of sheathing is saturated. When the roof heats up and expands slightly that may provide a better channel for any trapped water to flow. IIRC I believe you said that this area is downhill of the supply duct, so it is could be condensation collected from the days before.

That area of the roof will need to be replaced at some point. Until you get the ceiling dried out it may be difficult to really pinpoint the source. Even if you can not totally remove those boards directly around the supply duct it might be worthwhile to carefully cut or drill a hole into that layer without penetrating the roof to see if you get a more immediate flow when the AC is on. Of course it is up to you to decide how far to continue probing, I don't know what might become too destructive in trying to seek out the source. Whether it makes sense to first try and add insulation to see if that works. Though it seems that this whole section of roof may need to be replaced sooner or later.
That sheathing that is dripping is located right under the plywood layer. the plywood layer in some areas is completely soaked. Assuming that this issue is from the condensation, and that the plywood has been soaked for a while. what is the best way to dryout the "in-between" layers? the first layer above the joists are dry. it's like the wet plywood layer is "sandwiched" between two rubber roofs, and im not sure how to dry that part.
If I just leave it as is and close everything up with sheetrock and insulation, I feel like the water will never go away. should I close all the windows in the room, and just run my dehumidifier non stop all day long for a week straight? or what do you suggest?

I actually stopped using my AC for the last couple of days to see how the dripping goes. unfortunately today is a rather cool day (rainy), so I based on my experience of having the water drip in the late afternoon when it's hot and sunny, I don't expect it to happen today.
That said, I agree that this roof will have to be replaced, and I plan on doing that once I have found the source of the leak. I would hate to spend all the money to replace the roof and still run into the same leaking issue because it was not a "roof" issue.
 

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No, the plywood was from the previous roofing system. the latest roof I put on was to fix a pitching problem towards the back of the house, and that part needed new plywood, which was done, and then a new rubber roof(membrane) was torched over the repaired part and the rest of the roof.
If this , if that. A lot of ideas go thru the head but really hard to be sure of anything.

I was thinking if plywood was put down in wet conditions it would not be able to dry. but you would be hard pressed to get 40%, I think.
 

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Discussion Starter #103
If this , if that. A lot of ideas go thru the head but really hard to be sure of anything.

I was thinking if plywood was put down in wet conditions it would not be able to dry. but you would be hard pressed to get 40%, I think.
Im thinking that there might have been a leak on the roof plus all of the non stop condensation from the ductwork must have contributed to this. When the plywood was first put on, it was dry, but that was back in 2012.
 

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Im thinking that there might have been a leak on the roof plus all of the non stop condensation from the ductwork must have contributed to this. When the plywood was first put on, it was dry, but that was back in 2012.
So. even of you removed as much as you could of the lower levels it would take for ever to dry the wet layer from just one side.
 

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Discussion Starter #105
So. even of you removed as much as you could of the lower levels it would take for ever to dry the wet layer from just one side.
how long do you think it will take to dry?, weeks? what if I closed up the room and just ran the de-humidifier?
 

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how long do you think it will take to dry?, weeks? what if I closed up the room and just ran the de-humidifier?
To many what if's and what about that's to even suggest a guess.



I think if you can prove it is not new water from hot air you would say it is old water that has been trapped for years.

If it is old water that is dripping in the one hole in the old roof, could you just seal the old roof from where you are and leave the water there.
 

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That sheathing that is dripping is located right under the plywood layer. the plywood layer in some areas is completely soaked. Assuming that this issue is from the condensation, and that the plywood has been soaked for a while. what is the best way to dryout the "in-between" layers? the first layer above the joists are dry. it's like the wet plywood layer is "sandwiched" between two rubber roofs, and im not sure how to dry that part.
If I just leave it as is and close everything up with sheetrock and insulation, I feel like the water will never go away. should I close all the windows in the room, and just run my dehumidifier non stop all day long for a week straight? or what do you suggest?

I actually stopped using my AC for the last couple of days to see how the dripping goes. unfortunately today is a rather cool day (rainy), so I based on my experience of having the water drip in the late afternoon when it's hot and sunny, I don't expect it to happen today.
That said, I agree that this roof will have to be replaced, and I plan on doing that once I have found the source of the leak. I would hate to spend all the money to replace the roof and still run into the same leaking issue because it was not a "roof" issue.
If you insulated the duct at the same time as fixing/replacing the roof then all possibilities should have been taken care of? Given that you have already put a scope inside the duct and don't see water following inside the duct down from the A/C unit itself.

I think it may be a question of how long will the current roof last as is without causing more issues. That if you you insulated the duct and that stopped more water from leaking in, and let the ceiling dry out and sealed it up underneath to protect the air in your living space, whether it is worth trying to do them separately or together.
 

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Discussion Starter #108
how long do you think it will take to dry?, weeks? what if I closed up the room and just ran the de-humidifier?
To many what if's and what about that's to even suggest a guess.



I think if you can prove it is not new water from hot air you would say it is old water that has been trapped for years.

If it is old water that is dripping in the one hole in the old roof, could you just seal the old roof from where you are and leave the water there.
Fair enough. The plan is I’m going to do some more cutting tomorrow right next to the vent and see if anything else drips down. And I’m waiting for some hvac speciallists to come over and assess the best way to insulate the ductwork. Then after insulating, I’ll run the AC non stop and see I can get a leak to form.
 

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Discussion Starter #109
That sheathing that is dripping is located right under the plywood layer. the plywood layer in some areas is completely soaked. Assuming that this issue is from the condensation, and that the plywood has been soaked for a while. what is the best way to dryout the "in-between" layers? the first layer above the joists are dry. it's like the wet plywood layer is "sandwiched" between two rubber roofs, and im not sure how to dry that part.
If I just leave it as is and close everything up with sheetrock and insulation, I feel like the water will never go away. should I close all the windows in the room, and just run my dehumidifier non stop all day long for a week straight? or what do you suggest?

I actually stopped using my AC for the last couple of days to see how the dripping goes. unfortunately today is a rather cool day (rainy), so I based on my experience of having the water drip in the late afternoon when it's hot and sunny, I don't expect it to happen today.
That said, I agree that this roof will have to be replaced, and I plan on doing that once I have found the source of the leak. I would hate to spend all the money to replace the roof and still run into the same leaking issue because it was not a "roof" issue.
If you insulated the duct at the same time as fixing/replacing the roof then all possibilities should have been taken care of? Given that you have already put a scope inside the duct and don't see water following inside the duct down from the A/C unit itself.

I think it may be a question of how long will the current roof last as is without causing more issues. That if you you insulated the duct and that stopped more water from leaking in, and let the ceiling dry out and sealed it up underneath to protect the air in your living space, whether it is worth trying to do them separately or together.
I really don’t mind if i do both at the same time. That is until I look at the dollars involved. Fixing the roof properly will involve taking the roof down to the single decking. Which is very expensive. And then insulating the main supply is not cheap either because of the cutting required and then applying the insulation internally. What would doubly hurt is if I still get a leak even after both are done.
I suppose if I’m redoing the roof I can add insulation to the ducting at that point. So then I can add insulation externally and it might be cheaper.
I received a quote for redoing all the ducting from scratch and it was quite insane. I think that doing it from scratch is not an option at this point.
 

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Discussion Starter #110
Another thing is that since leaving the AC off the upstairs is pretty hot and humid. 80f and 70% humidity. If I get a window ac Or standing unit to cool down the upstairs Temporarily, do you think that will cause any condensation or other water issues near the ceiling\ roof?
I’m thinking the heat and humidity up there is probably not conducive to faster drying times
 

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Another thing is that since leaving the AC off the upstairs is pretty hot and humid. 80f and 70% humidity. If I get a window ac Or standing unit to cool down the upstairs Temporarily, do you think that will cause any condensation or other water issues near the ceiling\ roof?
I’m thinking the heat and humidity up there is probably not conducive to faster drying times
Getting a window unit and continuing to run your dehumidifier should help lower the humidity so that the exposed sheathing dries out faster. I do not have a feel for how long that would take, but should definitely answer the question of where the water is coming from.

Personally I would not replace all those ducts, but cut open that section to insulate (if necessary) whenever the appropriate time comes.
 

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Discussion Starter #112
Getting a window unit and continuing to run your dehumidifier should help lower the humidity so that the exposed sheathing dries out faster. I do not have a feel for how long that would take, but should definitely answer the question of where the water is coming from.

Personally I would not replace all those ducts, but cut open that section to insulate (if necessary) whenever the appropriate time comes.
I rigged up a floor unit with my casement window today (pain in the butt), but it was running for most of the day and helped with the humidity. So I still got a few drips today, but surely less than previous days when I had the central AC on all day. Now the question is are those drips just residual water coming out of the area that were opened up by me most recently? It all seems to occur in the afternoon when it's max temp/humidity in the ceiling area (today @2:30PM it was 110F, 60%Humidity).
Tomorrow should be another scorcher, so I'll be looking out to see how the dripping going with just the portable AC. I've had no central AC for 3 days now (brutal as well)
Lastly, I did talk to a contractor today and they mentioned the same thing about not removing all the ducts, but to cut out part of the main supply duct from the top, and replace with a new pre-insulated section. he said it would be too hard to apply it in place. I think I agree with him. It took an hour to explain to him and walk him through my whole through process, because he kept dismissing that condensation could cause all that damage. That is until I gave him the whole back story of how this might have been happening for many years.
Assuming that the drips disappear in the next couple of days. what do you think the next step should be? Should I re-run the central AC non-stop for a few days to see if it starts dripping again to prove that it is the uninsulated supply duct causing issues (im just afraid that it might take longer to manifest itself after all of the dehumidifying / portable AC and a couple of days might not even show up, thus giving me false data)? or should I just replace the duct (insulate) first, and then try to run the AC non stop for a few days / week to see if the dripping occurs again.
or should I do something else?
 

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I rigged up a floor unit with my casement window today (pain in the butt), but it was running for most of the day and helped with the humidity. So I still got a few drips today, but surely less than previous days when I had the central AC on all day. Now the question is are those drips just residual water coming out of the area that were opened up by me most recently? It all seems to occur in the afternoon when it's max temp/humidity in the ceiling area (today @2:30PM it was 110F, 60%Humidity).
Tomorrow should be another scorcher, so I'll be looking out to see how the dripping going with just the portable AC. I've had no central AC for 3 days now (brutal as well)
Lastly, I did talk to a contractor today and they mentioned the same thing about not removing all the ducts, but to cut out part of the main supply duct from the top, and replace with a new pre-insulated section. he said it would be too hard to apply it in place. I think I agree with him. It took an hour to explain to him and walk him through my whole through process, because he kept dismissing that condensation could cause all that damage. That is until I gave him the whole back story of how this might have been happening for many years.
Assuming that the drips disappear in the next couple of days. what do you think the next step should be? Should I re-run the central AC non-stop for a few days to see if it starts dripping again to prove that it is the uninsulated supply duct causing issues (im just afraid that it might take longer to manifest itself after all of the dehumidifying / portable AC and a couple of days might not even show up, thus giving me false data)? or should I just replace the duct (insulate) first, and then try to run the AC non stop for a few days / week to see if the dripping occurs again.
or should I do something else?
That is what I would do, since you are trying to confirm the source.

Rather than replace the uninsulated section you could cut out a 2 foot section or so that is above the roof. Cutting at least 6" above the roof, being careful not to disturb the roof penetration so that another leak is not created. Then insulate the inside of the duct like the other supply branches by gluing in some panels. Since it seems like you could get by with less than an arms length of insulation for the section that passes through the roof and insulate the section that was cut out while you are at it. I say that assuming the insulation panels can be glued with construction adhesive or similar to the inside of the duct. Putting the duct back together could be difficult without some kind of coupler/sleeve that could be slid up and down the outside of the duct and then fastened/taped back in place after reassembly. Now all that may be a bad idea, I have certainly never done it.
 

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Discussion Starter #114 (Edited)
That is what I would do, since you are trying to confirm the source.

Rather than replace the uninsulated section you could cut out a 2 foot section or so that is above the roof. Cutting at least 6" above the roof, being careful not to disturb the roof penetration so that another leak is not created. Then insulate the inside of the duct like the other supply branches by gluing in some panels. Since it seems like you could get by with less than an arms length of insulation for the section that passes through the roof and insulate the section that was cut out while you are at it. I say that assuming the insulation panels can be glued with construction adhesive or similar to the inside of the duct. Putting the duct back together could be difficult without some kind of coupler/sleeve that could be slid up and down the outside of the duct and then fastened/taped back in place after reassembly. Now all that may be a bad idea, I have certainly never done it.
The insulation job is going to be tough, which was confirmed by several contractors that I reached out to. None of them thought it would be straightforward. That being said I did hire a guy that is going to build me a new section of ductwork that will replace the old uninsulated part in the supply duct. He said he will insulated they interior AND exterior so if there is a leak it won’t be from condensation on the main supply duct. Also today was a very hot day and on cue, right in the afternoon time when peak temps and sun were being reached I started getting dripping again. This time more water was coming from one of the holes I cut further upstream.
I’m not sure what’s happening. Is this just water that’s trapped in the plywood releasing because of the super hot and humid temps in the ceiling layer?
I’m starting to have inklings of doubt that the issues are from condensation and instead going back to the original theory that I had roof leaks over time which got trapped between the two vapor barriers and now that I cut additional holes it has a chance to “release”. However maybe it can be years of condensation buildup which has nowhere to go until now too.
Today I spent some time and tried to cut some holes right next to the vent. So I cut all the layers except for the final plywood layer before the newest roof. Note that the plywood was completely damp when I finally cut to that section.
I’m thinking I’m going to just run the window ac only for a few more days to see if the “sweating” stops. If it doesn’t then what do you guys think? I don’t believe the contractor will have the new duct assembled until the end of the week and then he’ll have to find some time (dry weather)to install. So it might not be done until next week. Should I wait until then to test out the AC again now that I have some holes cut closer to the supply duct?
 

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Hopefully it will stop dripping in a few days with just the window A/C running, so that you can turn back on the central A/C to see what happens. But besides being really difficult to confirm a diagnosis earlier, since the insulation is no longer overhead any hot and humid air that was getting trapped around the duct before is more diffuse now, making the experiment less repeatable to perform right now.

It is really difficult to speculate on what you were seeing today. Was it trapped moisture getting a path to flow by the thermal expansion? Does your home act like a cold front to the warm humid air that is still creeping in from above? Though the latter seems kind of far fetched to me, maybe it is just the inverse of what happens in the winter time with a bathroom ceiling fan, where if the exhaust duct is not insulated, moisture in the warm house air will condense as it passes through the cold attic space and drip back down into the house.
 

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Discussion Starter #116
Hopefully it will stop dripping in a few days with just the window A/C running, so that you can turn back on the central A/C to see what happens. But besides being really difficult to confirm a diagnosis earlier, since the insulation is no longer overhead any hot and humid air that was getting trapped around the duct before is more diffuse now, making the experiment less repeatable to perform right now.

It is really difficult to speculate on what you were seeing today. Was it trapped moisture getting a path to flow by the thermal expansion? Does your home act like a cold front to the warm humid air that is still creeping in from above? Though the latter seems kind of far fetched to me, maybe it is just the inverse of what happens in the winter time with a bathroom ceiling fan, where if the exhaust duct is not insulated, moisture in the warm house air will condense as it passes through the cold attic space and drip back down into the house.
The contractors were actually able to come today to install the new insulated section of supply duct.once we started tearing apart the ductwork from the outside, upon breaking the roof / duct seal, we found some water trapped inside. it was basically under the outer two layers of roofing. I've included a link to a video of me pushing against the ductwork under an older layer of flashing/paint. I wonder if this is enough water to cause so much damage over time.
That said, in addition to adding the interior insulation in the new section, they adding foamular boards to the exterior to add even more insulation. I hope that's not too much. so with all this being done, I hope that it will eliminate any kind of condensation from being the source of the dripping. now I have to wait until tomorrow before turning on the AC. I don't want to mess up the curing of the Karnak (how long should I wait? the final coat was applied around 5PM tonight). and they layered it on thick.

https://flic.kr/p/2jviucd
 

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That video is pretty interesting. With the water visible that high up it makes one wonder if some or all the water was not from condensation running down from the outside. In any case with the work done today, hopefully the condensation will stop and the flashing will keep out all external sources of water.

Good Luck and fingers crossed.
 

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Discussion Starter #119
That video is pretty interesting. With the water visible that high up it makes one wonder if some or all the water was not from condensation running down from the outside. In any case with the work done today, hopefully the condensation will stop and the flashing will keep out all external sources of water.

Good Luck and fingers crossed.
Thanks!
Sorry I didn’t understand fully your comment. We’re you saying that you think that most of the damage could have been from condensation in that part? Or you meant that it is not likely that it’s just the condensation and it could be other factors (like roof leak)
The fact that I saw all that water flowing to the top from pushing on it made me think that over 8 years that this water issue can compound.
As for why the ceiling is still dripping, your explanation of “thermal expansion” makes a lot of sense too. When it’s hotter out the water will take up more volume and is probably being “expelled” from the plywood, which when I last measured was about 40-50% moisture content.
It sucks to see the water under the duct like that but at the same time it’s promising as it’s proving our theory of duct condensation being the culprit behind all of this damage.
 

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Discussion Starter #120
Hopefully that does the trick. I don't know how long you wait.
Thanks Neal! I didn’t think it would be so involved to get a couple of pieces of duct work out. I didn’t think about how interconnected all of the pieces were and that you couldn’t just “cut” one section and slide the other in. Plus having to remove all the old layers of roofing a material, flashing, etc were all royal pains.
I can’t wait to be able to turn on the AC again to test and see how the dripping goes. I think I’ll play it safe and wait until tomorrow afternoon for the full 24 hours. That said it’s supposed to rain like crazy over the next few days. I hope that Karnak holds up!
 
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