Another roof question - what should I see when shingles join up against a wall

[joefrompa]

Hi all,

I've had a roof leak for 9 months now (appeared 2 weeks after I moved in...suspicious to say the least) - I have been unable to figure out WHAT is causing it/what's wrong. It only travels through about 3' of attic space, down through attic subflooring (like 1.5" wood flooring) and then down a joist and into my bucket. No real room to create damage and I've got it airing out all the time in the open space.

Anyway, every shingle is in place and visible flashing is fine. I've caulked every visible seam/area needing caulking and the next rain storm it was exactly the same. The area where the leak is occuring appears to be where the 2nd story meet and has a seperation, seen in this picture:

Now, notice where the 2nd story juts forward about 4' on that first story roof. What should I see where that roof and wall meet?

What I just realized is that what I am seeing is shingles butting up against a faux-tudor trim piece. Shingles are directly abutting trim as the roof slopes downwards.

Now this roof is like 15 years old and as far as I know all the trim pieces are as well. My home inspector (10 months ago) said the roof looked 5 years old, it was in such good shape, and I agree from my novice eye.

And I'm guessing that underneath that trim and the shingles is a piece of flashing. But I don't understand how it's creating a water-tight barrier and I'm guessing that's where my water is coming in.

So - what should it look like in those situations? How should a roof go up into a sloping side wall? Or is this setup fine?

Joe

 

[woodgeek]

a random thought--I have a split level house/roof, and have about 25' of a joint just like that, and it always leaked. The answer, of course, is that there needs to be metal flashing woven in with the shingles, which run behind the siding of the house (your guess). The rub is if a (hack) installer who puts a second layer of shingles down just butts them to the wall (rather than pulling the siding and reflashing). IOW, in a big fraction of cases the second layer is installed incorrectly--water runs under it and relies on the integrity of the original roof and flashing (now way past their design life) to do the job. In my case, this was on a lee side, so it only leaked when we got a driving rain in an unusual direction--not a big volume. It was also clear that the previous HO had been up there every few years caulking the crap out of it for a hack repair of a hack install.

So, do you have 2 layers? My guess is the flashing is in the first layer.

 

[joefrompa]

I spent some more time searching this out and what I found is that:

1. One approach is to use a 90 degree shingle that goes up the vertical wall a few inches and acts as a step flashing and then properly integrate it back with the roof shingles

2. There is a installation kit that moves water away from the vertical wall altogether by stepping out from the wall several inches over the roof and shedding the water there.

3. Some form of metal step flashing up the side and tying in with the back corner wall.


Roofing company (reputable, large, well established) coming out on Thursday to check things out and give me an estimate. We'll see what they have to say and how much they'll charge me for this.

 

[Hogwildz]

Tough to tell from the photo. But anytime a roof meets a wall:
On the sides it has step flashings under each shingle as they are run up along the wall. Usually, the original roof is installed before the siding. So the step flashings should be behind the siding. And the shingles also may be under the siding as they siding is usually installed after. At the front wall the roof should have a base flashing going up the wall with a bend at the angle change, and then onto the shingles, with a cap shingle on top.
Most time if the roof is re-roofed, or "shingled over" the old roof, there is no additional flashings installed. And yes, now you must rely on the old flashings being sound. Most roofers would check them as they go. Realistically flashing should last forever. They are not really exposed expect in a few minimal spots.
The water could also be coming in from the upper floor eave and running down behind the siding or wall. Not saying this is the case but a possibility.
Best bet is to spray a hose up there,s tart low and work your way up until you see water coming in. That will give you the area, then narrow it down. Could be a small void in the flashing. Could be getting in along side the window if not properly flashed or no J channel. Could be several things.

 

[Hogwildz]

If the flashing is only under the tudor trim board, and not behind the entire siding surface, water could be blowing against the wall and running down behind the board & the base flashing, thus running behind everything and into the space below.

 

[djblech]

Step flashing should always be used agianst a wall. The 90* tin shingles are applied with each course, sealing the previous one. Keep nails toward the top of the metal shingle were they will be covered by the next metal shingle. Ice and water barrier should be applied first flat and up the wall. This seals the nails as they penetrate.
Doug

 

[fishingpol]

Water leaks are a funny thing. Sometimes if it is a wind driven rain, it will leak and other times a calm rainstorm will not show the leak. If you have attic access, start at the ridge and look down the rafters from there. Is there any evidence of staining? If it is a leak at every storm, it should have discoloration somewhere on the framing and that would be your starting point. A moisture meter can help also on the underside of the roof sheathing. If you can get a better picture, we can give a better idea where to look.

 

[btuser]

Gotta get a roofer. No telling where the water is coming from. My last leak was from 30' away.

 

[joefrompa]

Roofer came out today. He showed me where the flashing under the shingles and up under the siding is improper and water is getting in. He said the siding (asbestos shingle) is not a "take off and put back" siding at this stage, and that our best bet is to remove the siding in question, reflash where it joins with the house, and then put all new siding up.

I have not yet gotten a quote, but I'm quite concerned about the possible expense of removing and replacing the asbestos siding. Further - I'm interested in re-siding the entire house. We'll see how much they quote me....

 

[woodgeek]

On the siding, get a second opinion--I too had cement asbestos siding, and I needed to flash behind it when I got a new roof last fall. I thought the siding issue would kill the budget and be a PITA and the roofer was actually non-plussed. Unlike wooden shingles, that I had had experience with, which are massive overlapped, the cement guys have like a 1/2" of overlap and are pretty easy to pull and renail w/o doing the whole wall. Of course, you should buy non-asbestos shingles that match the texture, in case you break one of the old ones. Worst case, you'll have to paint the siding afterwards to get 'em to match.

 

[peakbagger]

Removing asbestos shingles isnt that tough or particularly hazardous as the asbestos is encapsulated. Generally, you have to keep it wet and avoid breaking the shingles by throwing them to the ground. Most firms use a continuous fine misting head to keep it wet. Once the shingles are removed they need to be immediately double bagged so dont throw them down on the ground in a pile and then bag them. Once its down, the PITA is legally disposing of it. In many areas, you need to double bag it in heavy duty plastic bags and identify it. It has to be land filled at a facility that is licensed to handle it. Some contractors make a bundle on asbestos shingles as they scare the homeowner into paying a big extra for asbestos removal.

Depressingly in many areas, unscrupluous people hire day laborers to do the removal and find a vacant lot to dump it in.

Some jurisdictions lump all asbestos into one category, if so it can get real expensive as friable asbesots (like insulation) is nasty stuff and requires trained crews, containments and air sampling.