Got a stain on the ceiling in a upstairs room. It's a vaulted area in the middle of the room. It goes up vertical about 6", then 45-deg up another 10" or so, then flat.

Right at the vertical/45 is a brownish stain, right where the angled piece of drywall hits the short vertical piece.

I thought "great,I have a leak" so I climbed in the attic to figure out what was going on and could not find any wet areas on the attic side of the drywall, Even went back onto the bedroom an poked a straightened coat hanger up thru the dryall to make sure I was in the right place. Back side of roof was also dry.

Pulled back the blown in insulation all around where the stain is located and all the drywall and wood is dry with no signs of any water damage. No leaks from the roof either. It was raining this Saturday all day, so i went up again that morning and still can't find anything. There is a capped off vent pipe that went to a wet bar on the 1st floor I removed and capped the vent in the attic, but that is bone dry. Same with the insulation, I can't find any damp or wet areas in the attic around the stained area or above it (I checked all the way up to the upper part of the vaulted ceiling to make sure it wasn't draining 'downhill' to the lower joint).

A lot of the rafters/joists have the orange sticky looking stuff on them (I think it's resin from searching on google). There was a little bit of that at the coat hanger hole, but not a lot.

What else could it be?

Raccoon pee

Pine Knots are full of sap, as is "green" lumber ... most often found in spec/tract homes where some of these framers do not cull and return to supply yards when in a hurry.

Once the sap has finally done all the damage it can, then 1st class surface sealers, etc. will cover up. An expert at a Devoe paint shop will walk you through this.

Leaks DO travel clandestine many yards before they exhibit, some with no fingerprints nor trails but think your sleuthing has ruled this out.

We like framing specs with #2/stud grade S-P-F studs and #2SYP, all of which are stamped, if you want to do more research & report. No problems reported in this vein.

tgivaughn said:

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Pine Knots are full of sap, as is "green" lumber ... most often found in spec/tract homes where some of these framers do not cull and return to supply yards when in a hurry.

Once the sap has finally done all the damage it can, then 1st class surface sealers, etc. will cover up. An expert at a Devoe paint shop will walk you through this.

Leaks DO travel clandestine many yards before they exhibit, some with no fingerprints nor trails but think your sleuthing has ruled this out.

We like framing specs with #2/stud grade S-P-F studs and #2SYP, all of which are stamped, if you want to do more research & report. No problems reported in this vein.

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House is 30-years old...I'd think the pine sap would have come out by now.

I forgot to note that it showed up when we had some unusually warm weather, than that sudden cold snap (like below freezing for over a week) in KC when half the country froze. I was wondering if it was maybe condensation from the attic being warm, then suddenly everything got really cold really fast?

Also, the spot is like 3-feet long. It's not just one place that might be hidden under a rafter/joist. I would think I'd see tons of water damage on the back side of the drywall in the attic.

could a leak be running horizontal along the seam rather than vertically down the sheetrock?

could it be condensation forming on the old vent then dripping when it got warm? maybe stuff the old vent with insulation and wrap it?

I'd suggest purchasing a moisture meter from Home Depot, or your favorite online retailer, and measuring the moisture content of the stain, and surrounding Sheetrock for a baseline. Measure it again through the week and take note of weather conditions. After a good soaking rain, measure again.

Something wicked out and measuring moisture directly can help shed light on these things. Leaks and moisture can travel a long way as someone said earlier. But it's also possible to have intermittent leaks of all kind, plumbing, roofing, who knows. But that's why the moisture meter can help determine where to look next. I've chased roof leaks for months because it only leaked with a 5mph north wind on days that were between 50 and 60. Of course that's exaggerated but the point is water can be fickle. I've also chased roof leaks only to find ac condensate drains or leaking plumbing pipes were the cause. So "everything" is suspicious.

agracer said:

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tgivaughn said:

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Pine Knots are full of sap, as is "green" lumber ... most often found in spec/tract homes where some of these framers do not cull and return to supply yards when in a hurry.

Once the sap has finally done all the damage it can, then 1st class surface sealers, etc. will cover up. An expert at a Devoe paint shop will walk you through this.

Leaks DO travel clandestine many yards before they exhibit, some with no fingerprints nor trails but think your sleuthing has ruled this out.

We like framing specs with #2/stud grade S-P-F studs and #2SYP, all of which are stamped, if you want to do more research & report. No problems reported in this vein.

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House is 30-years old...I'd think the pine sap would have come out by now.

I forgot to note that it showed up when we had some unusually warm weather, than that sudden cold snap (like below freezing for over a week) in KC when half the country froze. I was wondering if it was maybe condensation from the attic being warm, then suddenly everything got really cold really fast?

Also, the spot is like 3-feet long. It's not just one place that might be hidden under a rafter/joist. I would think I'd see tons of water damage on the back side of the drywall in the attic.

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My house is 30 years old and my garage still leaks sap, especially in the summer.

RoyVal said:

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agracer said:

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tgivaughn said:

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Pine Knots are full of sap, as is "green" lumber ... most often found in spec/tract homes where some of these framers do not cull and return to supply yards when in a hurry.

Once the sap has finally done all the damage it can, then 1st class surface sealers, etc. will cover up. An expert at a Devoe paint shop will walk you through this.

Leaks DO travel clandestine many yards before they exhibit, some with no fingerprints nor trails but think your sleuthing has ruled this out.

We like framing specs with #2/stud grade S-P-F studs and #2SYP, all of which are stamped, if you want to do more research & report. No problems reported in this vein.

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House is 30-years old...I'd think the pine sap would have come out by now.

I forgot to note that it showed up when we had some unusually warm weather, than that sudden cold snap (like below freezing for over a week) in KC when half the country froze. I was wondering if it was maybe condensation from the attic being warm, then suddenly everything got really cold really fast?

Also, the spot is like 3-feet long. It's not just one place that might be hidden under a rafter/joist. I would think I'd see tons of water damage on the back side of the drywall in the attic.

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My house is 30 years old and my garage still leaks sap, especially in the summer.

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it's winter and was very cold out when I noticed.

I don't wonder if the old vent line had some rain water in it, then it turned bitter cold and the water inside froze or got cold when the weather turned, but the attic was still warm enough to cause condensation which dripped off the vent. The vent ends ~2-feet horizontal and above the location of the stain. It's not right above the stain.

I would just think I'd see some damage or stain on the attic side, and I can't find anything. The stain is ~3-feet long horizontal and between 1" - 4" wide across the length of the stain. So it's not hidden behind a joist or rafter or support board. If it was coming from the vent, it would have to drip down onto the angled joist then go down the joist to the vertical/angled joint where the stain is located. But the stain is ONLY at that joint, no where else nor directly below the vent line.

I'll keep looking. Next time my brother's in town I'll have him go up with me with some plastic bags and gather up the blow in insulation all around the stain and see what we can find. Doing it alone with a flashlight is a PITA.

Pictures

Condensation?