Why Leaking Roof under Dormer / hole in OSB!!!

MB1

Ok, please hold back the jokes and take it easy on me as I describe my issue...this is my first post :-) I've heard good things about this group, so here it goes:

I have been getting some discoloration in my living room ceiling starting just below where dormer meets the main roof (a flat, not A framed dormer). I inspected the area of the main roof right under the shingled dormer and found the OSB rotted out. (good fire starter and sawdust)

The valley is completely shingled where the dormer meets the main roof and there is little slope where the water should be running off from the valley to the main roof.

What I'm not sure is whether the water is coming through the bottom corner under the flashing, or pooling somewhere and coming in under the main roof between the corner of the valley and wall of the dormer (or maybe it doesn't matter?).

Any suggestions on how to figure this out, so I can identify my problem area before patching the damaged area below? [Being a newbie to roof repair, I'm trying to avoid tearing up more than I need to]

Thank you in advance for any advice!

rossfingal

Hi!
Posting some pictures would help!

rossfingal

MB1

Thanks. Will get them on Tues, weather permitting.

rossfingal

Good!


rossfingal

titanoman

On a dry day take a hose to it and see if that tells you anything.

Sent from a Samsung Galaxy S2

Roofmaster417

I have seen the same when a valley isn't laced with the first shingle entering the valley.

If the last piece of step flashing closing the dormer wall is improper.

If the apron that meets the lace is short.

If the laced shingle is too short into the valley.

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MB1

Here are the photos of my leaking roof/dormer...ugly ay? The leak problem is the corner furthest from view. (5 more detailed photos) I appreciate any comments. At this point, I need to patch this up ASAP to prevent leaking given rain is expected on Thursday. Any suggestions on how to do that so I don't get water in the house? (I'm in San Jose, CA) The short term fix need not be pretty given it only needs to be temporary since I will replace the entire roof soon (I will start a separate thread on this. I need input why the roof is failing...My 8 year old shingles have spidering/cracks everywhere except the top 3 rows below the ridge...not sure if that is a venting and/or product issue, as well as overexposed shingle issue per the "professional" roofers that looked at my roof today.

P.S. As you can see, I did not want to pour water on my roof today to locate where the water is coming in given the hole and laminate flooring below.

Thank you all for your help!!!!

-Marcum

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titanoman

What a mess. All that has to be torn off, then woven and flashed properly.

joecaption

I also see what looks like where that metal looking roof dumps all it's water right up againt the "dormers" fashia. Not a great plan.
Looks like a drunkun salor did the weaving on those shingles.
If they had of been 30 year shingles they may not have leaked because there's no tabs for water to get under every few inches. I would have also used strorm and ice shield in those valleys.

MB1

So, short term, how do I "patch" this up until I get my new roof? One roofer today suggested that I just get something like roof leak stopper (rubberized roof patch) and a trowel, and just cover the entire valley and under the dormer (once I put the shingles back, and add some mesh backing to the hole). Do you think that may be a temporary fix for the next 7-30 days?

Thank you!

MB1

PS. Joe, I think the metal looking stuff you are referring to is the 1x2 inch pvc drip edge?

titanoman

Just keep in mind whatever you put
down is going to have to be ripped back out in 7-30 days.

MB1

Titanoman, are you implying that patching the entire dormer area with the goop is going to create a problem for the roofer coming in? Is this stuff going to do the trick, or is there a better approach short term?

titanoman

I wouldn't do anything to it if you're going to put a new roof on it within a month.

MB1

???? There is rain in the forecast and I have a hole in my roof....I have to do something to keep the water out....am I missing your humor somewhere?