My question: How can I search for the origin of the leak?

I have had a problem leak in my living room ceiling for a year. Every time I think I've fixed it, it comes back the next prolonged rain. I have taken off the entire roof over that area. I have removed and rebuit the balcony with a steeper slope. I have used roofing felt, shingles, flashing, and waterproof sealer to ensure water travels as it is supposed to. I cannot figure out where the water is coming from and it is very aggrivating. Looks like I am going to have to remove the drywall (again) and start digging around (again). It's either that, or I call a priest to end this poltergeist.


This is the leak after 12 hours of good rain (taken this morning, 6am).


This is what the area looked like last December. I was still working on the exterior, so some of the siding wasn't done yet. At that time, I thought the water might be getting in under the shingles at the bottom of the roof, or coming in around the corner of the wall. I made sure flashing and roofing was properly installed to prevent water from coming in.


This is what it looked like over the summer when I pulled up the balcony and rebuilt it with a steeper slope.


New sheathing over balcony. I then put down heavy paper, adhesive, rolled shingle, and coated the whole balcony with aluminum roof coating. I have traced the water path from the roof peak down to where the roof channel spills onto the balcony. I have checked the step flashing, corner flashing, and slope flashing to make sure water is flowing properly. My best guess is that the water is not coming from directly above, but is travelling from the outer edge of the garage area back to the beam, then coming down the beam and leaking through the ceiling.

 

You might as well open the ceiling & trace the water from the inside. You'll see marks on the joists. You have to replace that sheet rock anyway. You could also test it with a hose while the ceiling is opened.

 

If it ever stops raining, I'll remove the drywall again and try the hose trick.

I tried tracing the source of the water the last time I had the ceiling open. I thought it was coming from farther out on the balcony by slipping between some flashing and then making its way along the sub-floor back to the header. Once the water hits the header, it goes down, onto the drywall ceiling.

I took apart that area of the balcony, resealed everything, then put on the aluminum roof coating and made sure I painted two coats into the corner (where balcony floor meets exterior wall).

I really thought that took care of it, as I didn't see the leak for a few months, but now it's November and we've had steady rain the last couple of days. To my great disgust and sadness, the leak has returned.

 

Do you mean the first floor exterior wall? What about the windows above the balcony floor? Are they too far away from where you see the water?

 

No way is the way you did it not going to leak.
Still not enough slope.
Roll roofing which is the lowest of the low grade roofing and it's laid in the wrong direction plus it must have been laying on it's side at one point because it's all cracked.
Trim in direct contact with the roofing is going to rot in no time.
Felt is never going to prevent leaks.
Where's the metal flashing where the roof meets the low sloped roof?
Why is there caulking between the sections of plywood?

 

This may be way off the mark but I had a leak that I couldn't find the source for as well. In the end it turned out to be that the caulk around the plumbing vents had dried out and the water ran down the vent pipe, onto the top plate of my garage wall and then down into our bedroom. From 3 feet away, the vent seals looked good but when you got up close you could see they were dried out and peeled off with just a little pulling.