identifying source of mysterious ceiling leak

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Old 04-11-14, 01:50 PM
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identifying source of mysterious ceiling leak

Back in January, I posted in a different forum (http://www.doityourself.com/forum/pl...ling-leak.html) about a serious ceiling leak we encountered on the first floor of our two-story rowhouse one morning during an unusual cold spell (around 15 degrees). The weather was dry and the heat was running most of the night at a moderate temperature (68 degrees; the heat pump is on the roof). I called the contractor who renovated the house top-to-bottom before I purchased it four months ago. When he cut into the first floor ceiling, he was unable to find any leaks in the pipes above or tub above. Also checked the roof and the heat pump; neither appeared to be the source. Also had our home inspector take a look; his best guess was that it had something to do with some ice build-up he found in one of the bathroom exhaust vents on the roof, so we installed a different sort of vent (admittedly a pretty cosmetic fix) and the contractor repaired the ceiling. Our ceiling was open for a month without a re-occurrence.

Over time, the repaired first floor ceiling appeared to deteriorate somewhat: some bowing along the joists, some softer spots, some distortion of the paint (though no obvious water stains). Moreover, when we had another spell of 15 degree weather, some moisture cracks appeared in the same area of the house but this time on the ceiling on the 2nd floor, above one of the bathroom, along with some soft spots along the edges of the walls.

The house contractor is not the most creative thinker and is adamant that water must be leaking in from somewhere, even though the weather was dry when this originally happened. After searching at length for a cause, I'm wondering if the source could be condensation in the attic/crawlspace between the 2nd floor ceiling and the roof. The space is not accessible but there appears to be 3 feet or so between the ceiling and our flat roof. It is not vented, so could this plausibly explain the occurrence of a massive moisture problem on very cold, dry days? If so, is the fix to have a roofer install attic vents? Would I also then need to insulate the exhaust ducts, etc. that pass through that attic space to the roof?

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Old 04-11-14, 03:59 PM
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That would have to be a lot of condensation to make the joists bow. In fact, can you explain the joists bowing a little better? Is your water bill any higher than normal? How many years have you been in the house?
 
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Old 04-11-14, 04:08 PM
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I recall we are still waiting on pictures of the area to help us diagnose the problem. If you have a hand held shower arm, point the spray into the corners of the shower and see if there is leakage. Often times the corners are grouted and caulked and water gets past seals and into the wall cavity.
 
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Old 04-14-14, 03:14 PM
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Pulpo, been in the house six months, before which it was gutted and renovated: new roof, plumbing, electrical, HVAC, everything. Water bill is normal. This is pretty definitively not a plumbing issue at this point, given that the signs of moisture are also now above the second floor ceiling, where there is no plumbing. Didn't mean to suggest that the joists themselves are bowing; meant that the recently repaired ceiling/drywall along joists on the first floor ceiling has become somewhat warped, as if due to humidity.

Czizzi, unfortunately, pictures will not convey the symptoms at this point. I didn't take photos when the original leaks through the first floor ceiling occurred back in January, and photos don't really pick up the details of what I'm describing now on the first and second floor ceilings.
 
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Old 04-14-14, 04:33 PM
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Then let's go back to your original idea about the space between the second floor ceiling & the roof. You said that it's not vented & that there is really no access. I guess they choices would be to install 2 vents, on opposite sides of the house, to vent it or cut a 3x3 opening, in the ceiling, of the second floor bathroom. Would you be willing to do either of those two things?
 
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Old 04-14-14, 06:23 PM
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Hi nabbasza,
Cold weather leaks are indeed often a result of condensation and or resulting ice. When it is from ice that has accumulated over time, the water often appears during the first following warm spell. Where yours is happening during the cold spell it doesn't seem to be a perfect fit.

But, I would assume the source is warm air leaking into the troubled area and encountering those cold temperatures. Some areas to look for are recessed lights, plumbing chaseways, Gaps around showers or tubs, or leaking or disconnected bath exhaust fans. The source can be from the basement or anywhere inbetween.

Before you tear things apart I would suggest an infrared inspection. IR cameras are very sensitive to thermal differences caused by moisture and damp areas will often show up like a red flag. Some rental stores have IR cameras.

Pictures of the inside and outside of your home identifying the problem area may help as well as many here would be familiar with the construction behind the walls.

Bud
 
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Old 04-22-14, 12:12 PM
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Thanks all who responded. I've had a couple of roofers come out in the last week, and both found the new roof installed when the house was flipped last year to be pretty shoddy: installed new roof atop previous ones, poor flashing, etc. The thing is, one guy strongly recommended replacing the whole roof but couldn't explain why the moisture problem was apparent in the house only during very cold weather and not after a heavy rainstorm; the other guy chalked it up to condensation but said the moisture problem would persist even after fixing the flashing issues, installing vents, etc. because "the damage was done", and therefore he too recommended an entirely new roof. What do folks think? Am I getting taken for a ride? I acknowledge that the moisture has most probably done some damage, but its not clear to me why my moisture problem inside would persist if the flashing issues were fixed (to keep water out) and the ceiling crawl space vented (to relieve condensation). I bought this house 9 months ago and plan to probably sell it in a couple of years, so I'm understandably reluctant to shell out to replace the entire roof unless that is truly the only option.

I may also need to post in the roofing section at this point...
 
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Old 04-22-14, 02:52 PM
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I wouldn't install a new roof just yet. I don't see how it's going to solve the problem. If it's condensation, hot is meeting cold somewhere. From your previous descriptions, it seemed to point to above the second floor bathroom. Be a detective. Look from the outside with some binoculars.
 
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Old 04-22-14, 03:41 PM
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I recall we are still waiting on pictures of the area to help us diagnose the problem.
Czizzi, unfortunately, pictures will not convey the symptoms at this point.
Still waiting a visual so that someone can offer some more concrete assistance.

If you bring in a roofer for an opinion, (psst - he gets paid to install roofs), and Surprise!, he recommends a new roof. Bring in another roofer... surprise, he recommends another new roof. Neither has offered a solution or an explanation to the problem. This forum has some of the most talented people you will ever run into who offer suggestions based on experience, not profit. Give us some tools and info to assist, we have been asking. Your descriptions have not provided the necessary info for the community to form a consensus on what to recommend. I beg, start uploading pictures from every possible angle and visual or the $10,000 re-roof is your only option.
 
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Old 04-22-14, 05:39 PM
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Not trying to drive you mad, Czizzi...just didn't think these photos would be helpful. But perhaps I should be more faithful!

I've attached a few photos. I didn't take one back in January before the saturated areas were cut out of the first floor ceiling, but attached is a photo (#1) of what it looked like afterward.

The next three photos (2, 3, 4) are of the bathroom immediately above. It would appear the water flowed down the far wall (back side of tub) and right side wall (behind the toilet) down to the ceiling of the first floor below.

Tough to make out, but in 3 and 4 you can see some discoloration/staining/ cracking that appeared in that upstairs bathroom after another frigid spell in March. Presumably the insulation above absorbed a bunch of moisture.

Photo 5 is of the other 2nd floor bathroom. There is no apparent water damage in this one. It is separated from the bathroom in photos 2-4 by the wall behind the toilets (i.e. the toilets are roughly back to back). This bathroom also sits above a bathroom on the first floor (the door ajar on the right side of photo 1).

Finally, photo 6 is the only one I have of the roof at the moment (I don't have access to the roof, so can't get up there easily). This is roughly the roof area above where the moisture appeared on the 1st and 2nd floors. The skylight to the right of the frame sits above the bathroom in photo 5. The skylight needs to be replaced.

I've asked if one of the roofers that came by this week could share with me some of the photos he took of specific problem issues he identified...we'll see if he complies. Again, to emphasize, moisture has appeared indoors on extremely cold days (i.e. 15 degrees) but not noticeably during big rainstorms, like we had a few days ago.
 
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Old 04-22-14, 07:22 PM
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Why didn't you mention that AC unit before? Is that unit & the vent directly above the second floor bathroom? What's that raised section to the right of the vent & what appears to be a space, on the cover?
 
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Old 04-22-14, 08:18 PM
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The heat pump is actually mentioned both at the beginning of this thread and the original thread back in January. The unit itself is at least partially above the bathroom in photos 2-4, though the return duct isn't really... it's a few feet away (on the far right side of the shower in the master bathroom in photo 5). HVAC contractor checked out the heat pump the day after the January leak and all was operating properly; home inspector also doubted that was the source (the return duct is sloped back towards the unit rather than toward the joint with the house).

Not sure what you mean by the raised section to the right of the vent, empty space, etc. Are you referring to the HVAC duct or to one of the exhaust vents? And by raised section, are you referring to the wall separating the row house next door or referring to the skylight curb?
 
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Old 04-22-14, 09:30 PM
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If I was in your situation, I would first cut an access to the sealed attic space, going through the ceiling in one of the closets. You can frame the opening, and build a hinged, insulated panel for future use--even if just for taking a glance in there once in a while with a bright flash light. Then, if that doesn't show where the moisture is coming from, call around for a home inspector who has an IR camera and the skills to use it. An hour or two should only cost a few hundred bucks, max. Renting one yourself could be a waste of time, as knowing how to use it and what it's showing takes training that the rental place won't likely be able to provide.

My hunch goes with too much moisture, condensing in the sealed attic space, and then finding its way down to your ceilings. A few (well-installed) vents could fix the problem, and wouldn't cost nearly as much as a new roof. Another place to look would be the curb walls of the sky-lite--if they are not insulated, living space moisture could be condensing there and working its way down.
 
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Old 04-23-14, 06:11 AM
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Thank you - Keep 'em coming...

Does the plastic you have up on the ceiling "breathe"? Does it move with the wind? Pulse? or otherwise indicate that there is a breech in the roof membrane that would be letting air into the wall/ceiling cavity?

Do either of the toilets have any side to side motion indicating that they are a little loose? Just see if they rock back and forth at all. Especially with you sitting on them.

Rap on the floor in the areas around the toilet and see if the sound changes at all. If it is tile, you should hear a hollow sound if there is moisture damage.

I would like to see a closer picture of the shower glass and shower door along the base near the toilet and how it is constructed.

Referring to the roof picture, which of the 3 vents would represent the wall between the two showers. How is the wood that the heat pump sits on affixed to the roof? Which of the 3 vents had icing issues as pointed out in one of the original postings? Where is the duct work for the heated air from the handler located in relation to the return air duct on the roof?
 
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Old 04-23-14, 11:28 AM
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The raised section is between the vent & the wall the separates the buildings. I don't know how else to describe it.
 
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Old 04-24-14, 11:29 AM
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Pulpo: I believe you are referring to the skylight curb that lies between the white exhaust vent and the exterior wall.

BridgeMan, I'm inclined to agree that this is a condensation problem. A couple questions for my fellow native Oregonian:

1. If I open up the ceiling to take a look, what signs should I be looking for to differentiate condensation in that space from water that might have leaked through the roof above? Presumably now that temps are near 70 degrees, I won't be seeing the active condensation that may have occurred in the winter.

2. Since that attic space is sealed, I'm pretty sure the various exhaust vents passing through that space are not insulated (with the exception of the HVAC ducts running to/from the roof, which are insulated on the inside). If attic vents are installed, am I correct in presuming it would be wise to insulate those exhaust vents, lest I face the prospect of condensation accumulating in those vents due to the warmer air contained within coming into contact with the cold winter air in the vented attic?

Czizzi, in response to your questions:

When we had the plastic up on the ceiling in January, there did not appear to be any "pulsing" with the wind.

Toilets don't appear to be loose. Moreover, the plumbing underneath the toilets was exposed when the ceiling was open for a month - no leakage was apparent.

The exhaust vent that had the icing issue (photo 7, attached) was the one closest to the exterior wall (i.e. the rightmost of the two in the background with the metallic caps; it had a different cap at that time). I had turned on the two showers and their respective fans before I took this photo of the roof. Of those two in the background, I could feel air coming out of the one on the left; no air coming out of the one on the right, but from the sound of running/flowing water emanating from it, it seemed like it might be the vent for the drain/plumbing. The white curved vent in the foreground would, roughly, represent the wall between the two bathrooms (FYI, all of the photos I took are facing the same direction, ie towards the rear of the house).

To my knowledge, the wood on which the heat pump sits is not affixed to the roof.

The heated air duct is to the right in the roof photo, near the exterior wall. It comes down past the far wall of the shower. The return duct is unseen in that photo but lies to the left; the intake vent lies a few feet outside the bathroom with the tub (photo 8). Incidentally, I noticed some water stains around that return vent (photo 9) in the early fall, before the major moisture problems in the house became apparent during frigid winter cold spells. That duct is insulated on the inside; so could those stains be from condensation accumulating on the outside of the duct in the hot, unvented attic space in the summer??

Photos 10 and 11 attached of the shower.

It seems to me that if I install an access panel to the attic space, I ideally would want to do so in a spot where: 1) in the area where the moisture problems were concentrated and visible; 2) where I can view the bathroom exhaust ducts and verify they did not become detached or are otherwise venting into the attic space; 3) can insulate the exhaust ducts if attic vents are to be installed; 4) can replace any waterlogged insulation above the bathroom ceiling. The only way to satisfy those four conditions would seemingly be to install the access panel in one of the bathrooms...or is that a bad idea?
 
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Old 04-24-14, 02:56 PM
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I think that the skylight is leaking, but not the cause of your moisture issues other than the staining in the ceiling upstairs in the bathrooms.

I don't think it is flashing or roof related or you would have had issues with every rain storm (and it has been a wet first qtr of the year).

I don't think it is related to plumbing or venting or from bath fans.

I am suspicious of a brand new rooftop heat pump and the heated supply ducts where the insulation inside can not be scrutinized. I assume that the duct has insulation on the inside. Poorly installed, there could be sufficient access to cold spots which would account for condensation issues. Have you investigated that angle? Everything looks great from outside, but what does it look like inside?
 
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Old 04-24-14, 03:31 PM
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The icicles hanging from the white PVC vent indicate it's carrying lots of moisture. During cold spells, even enough that will build up to a heavy layer of ice inside, which could be melting and then finding its way out into the sealed attic space through a loose joint, when warm exhaust air flows through the vent. Plumbers and HVAC guys are not immune to forgetting to cement all joint fittings--I recently found a 3" toilet drain line in my crawl space with no cement in 2 of the 5 visible joints.

The skylite curb wall (left corner in same photo) looks like it could be saturated inside as well, based on the peeling topcoating.
 
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Old 04-24-14, 05:15 PM
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The skylight certainly needs replacing -- no doubt about that. It could be the cause of some of the ceiling staining on the right side of the tub (closer to the skylight)...I think that staining showed up gradually, while a crack and staining on the left side of the ceiling above the tub showed up suddenly after a spell of 15-degree weather.

I was suspicious of condensation in the ductwork when this first happened, but I was assured the duct is insulated on the inside; the return duct certainly is. Is there any way to confirm this is true for the heated duct as well, apart from detaching it on the roof and having a look?

BridgeMan, it certainly would not be surprising if the crew who did this renovation neglected to cement some fittings. Will have to look for that once a hole is cut in the ceiling.
 
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Old 04-24-14, 07:50 PM
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nabbasza, That area needs to be inspected closely. Somewhere around there is the cause of the problem. Cutting a hole in the bathroom ceiling should tell you a lot. There will be marks on the joists & who knows what else.
 
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