# Help with tricky valley



## wombosi (Apr 22, 2008)

My roof is about 15 years old and is leaking like a sieve in the valley next to the dormer. 
The roof to the left is roughly a 12" pitch. The one to the right is much steeper, probably a 14" pitch or more.
The valley is currently woven together with 3-tab shingles. Will replace with architectural shingles.

I'm wondering what the best approach would be in this situation with such steep pitches, and two different pitches.

I plan on ice and water shielding the bejeezus out of the entire thing.

Thanks!










edit: i'm leaning toward the closed cut or long island style.
i would start by shingling up the valley, then overlap the bigger roof onto the valley.
would this be good?


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## Slyfox (Jun 13, 2008)

It is some what of a tricky valley, eh.

My first thought would be to talk you into building a cricket/wash out, that would widen the distance from the right lower corner of the dormer to the valley, widen it by how much would depend on how you build the structure but it could easily create an 8" span with out it being overly noticeable from the ground.


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## Windows on Wash (Aug 30, 2011)

+1

Don't try to just remedy the problem with more sealant, ice/water, etc. There is no remedy for improper water flow other than re-routing it.


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## wombosi (Apr 22, 2008)

well, it's a horrible spot for a dormer, but i don't see how this could leak with ice and water shield in the valley and lapped up the side of the dormer in a continuous piece.
the cricket is an interesting idea, but i'm not going to do it.
i wonder if there would be a nice way of extending the shed roof of the dormer to die onto the steep slope to the right. 

thanks.


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## Roofmaster417 (Jun 9, 2010)

What a big big of a dormer in a very nasty spot.,.,I agree with Sly,,,,,Major wash of rain,sloppy area for snow and ice,,,,hmmmm,,,,,Stake the architect,,,


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## Michael Thomas (Jan 27, 2008)

Boy, that design is a nasty piece of work... were there chimney flashing leaks as well (mismatched singles at the chimney base and ridge)?

_______________

This is a case of aesthetics vs. function, especially as regards water running of the steeper pitched roof against the side of the dormer, but there is no reason why waterproof shingle underlayment (WSU) under a closed cut valley _should_ not work, assuming that it's done properly so as to protect the dormer.

However, from a water intrusion standpoint my recommendation would be a open cut valley above a 12-18" siding hold back above a continuous valley flashing running 12"-18" up the side of the dormer and incorporating the apron flashing below the dormer's lower edge: easier to keep free of debris (which will be an ever greater problem once that valley is done with architectural shingles (you should not use a woven valley with architectural shingles) and will be easier to inspect and service. Copper would be attractive there, once the patina forms.


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## Roofmaster417 (Jun 9, 2010)

After further observation of the photo,,,,You might get away with a pan that runs 5' to 6' up the side that is vulnerable,,,


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## Slyfox (Jun 13, 2008)

There are several routes to take, a few have already been mentioned and each will work assuming the valley is properly installed.

The difference between how you choose to go is longevity, meaning the water running off the right side and beating onto the side of the dormer is going to cause that area to deteriorate at a faster rate then the surrounding area.
A cricket installed to run a little more then half way up the right wall
(guest-o-mating) would create an 8/12, maybe 9/12 pitch cricket, thus increasing the longevity of that area to more like what would be expected of the shed roof slope.

Steeper slopes = faster water run off and less direct beating of the sun.
Lower slopes = slower water run off and more direct beating of the sun.

So a shingles on a steeper slope will have a longer expected life span than on a lower slope.

If you do like roofmaster suggested and create a wash out pan, meaning you would shingle both sides of the valley up to the bottom of the dormer install i&w shield, then a metal pan that covers the shingles you just installed and goes up the wall 12" too 18" and up the steeper slope 24" or more and up the valley several feet "the more the better" and then leave the pan exposed on the dormer side and shingle over it on the steeper side and up top were you decide to end it on the dormer side, you will speed up the water run off by eliminating the shingles and leaving a smooth metal surface there.


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## wombosi (Apr 22, 2008)

Michael Thomas said:


> Boy, that design is a nasty piece of work... were there chimney flashing leaks as well (mismatched singles at the chimney base and ridge)?
> 
> _______________
> 
> yes, the chimney was leaking badly. the roofer had bent up the copper counter flashing and installed aluminum step flashing. parts of the copper never got bend back down, and or blew off. plus the mason did a horrible job rebuilding the upper bit. so i repointed it, ripped off the shingles and aluminum, re-stepped in copper, re-countered in copper, and put back new shingles that don't quite match the faded black.


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## Michael Thomas (Jan 27, 2008)

wombosi said:


> yes, the chimney was leaking badly. the roofer had bent up the copper counter flashing and installed aluminum step flashing. parts of the copper never got bend back down, and or blew off. plus the mason did a horrible job rebuilding the upper bit. so i repointed it, ripped off the shingles and aluminum, re-stepped in copper, re-countered in copper, and put back new shingles that don't quite match the faded black.


I wasn't going to to there, but that chimney cap is its own can of worms.


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## wombosi (Apr 22, 2008)

Michael Thomas said:


> I wasn't going to to there, but that chimney cap is its own can of worms.


why? i installed it. the lack of the cap was the reason the chimney was so deteriorated and leaking.

i'm only trying to buy a year or two with the chimney, then it's getting torn down when i do a direct vent boiler.

i need a strategy with this roof. maybe i should tarp it and wait a year, and change the dormer design, move it over maybe.
maybe i should wait on the roof until the chimney comes down.

then again, it's leaking NOW.


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## Michael Thomas (Jan 27, 2008)

What's venting through the chimney?


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## wombosi (Apr 22, 2008)

Michael Thomas said:


> What's venting through the chimney?


My oil fired boiler.


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## Michael Thomas (Jan 27, 2008)

Is there a liner of any sort in the chimney?


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## wombosi (Apr 22, 2008)

Michael Thomas said:


> Is there a liner of any sort in the chimney?


the chimney from the roof up was redone before i bought the house. only that section has a ceramic flu. the rest of it is unlined, just brick. i've seen a few of the bump-outs on the first floor, and where the vent pipe goes in in the basement.
i realize the chimney is a piece of junk, but what does this have to do with the cap being a can of worms?


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## Gymschu (Dec 12, 2010)

.....


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## wombosi (Apr 22, 2008)

Gymschu said:


> That chimney cap looks kinda scary.


I don't give a damn about the chimney cap; I'm here to discuss the issue of re-roofing the valley.


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## Michael Thomas (Jan 27, 2008)

Well, first, the unlined potion of the chimney, especially above the roof, is going to experience excessive condensation, deteriorating the masonry. Second, a flue below that that style of cap is subject to rapid swings of air pressure as the wind shifts, which can influence the effectiveness of the draft. Third, that style of "rain cap" will do a poor job of keeping rain, snow and debris out of the chimney and off the exposed portions of the top of the chimney.

Here's a chimney I saw recently where such condensation had deteriorated the portion of a chimney below a clay tile flue installed from the level of the cap up only:


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## wombosi (Apr 22, 2008)

Well, the bit above the roof IS lined, and the top of the chimney under the cap has beveled mortar.

How could the chimney possibly be better protected from rain without the cap?

Anyway, like I said, I don't care about the chimney. If it lasts another two years that's all I want. And it's working just fine, and is a hell of a lot better than what it used to be before I fixed it.


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## kwikfishron (Mar 11, 2010)

wombosi said:


> i'm only trying to buy a year or two with the chimney, then it's getting torn down when i do a direct vent boiler.
> 
> i need a strategy with this roof. maybe i should tarp it and wait a year, and change the dormer design, move it over maybe.
> maybe i should wait on the roof until the chimney comes down.
> ...


I would move it. Not only because of the obvious that dormers in valleys are always bad news but just looking at it screams mistake. 

The things an eye sore sitting there like that and as long as it’s there regardless what you do in terms of water management it will always be a mistake.


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## tinner666 (Mar 14, 2005)

"edit: i'm leaning toward the closed cut or long island style.
i would start by shingling up the valley, then overlap the bigger roof onto the valley.
would this be good?"

I've seen them leak with 3 layers of I&W. If the roof is wrong, it's gonna leak. 

My options I'd offer would be:

1. Close it off by adding to the dormer.
2. Move or remove the dormer.
3. Faltten the valley between there so the exit is about 12" or so wider. Run the siding over under the exit, and you'll also have to step flash it into the steeper roof. Install flat-locked, soldered pans in the valley running 30" or so up each wall, etc, etc.


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## tinner666 (Mar 14, 2005)

Hey, it could be worse. This is a leaking roof I hope to get to work on some day. There's a tree growing up there too.


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## wombosi (Apr 22, 2008)

tinner666 said:


> Hey, it could be worse. This is a leaking roof I hope to get to work on some day. There's a tree growing up there too.


hey tinner, 
i appreciate that man! makes me feel a bit better.
leaning towards not extending the dormer, and making an open copper valley that laps up the side of the dormer with sottered joints.


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## tinner666 (Mar 14, 2005)

It can be done, but matching that siding to widen the exit could be a bear to match.


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## tinner666 (Mar 14, 2005)

How much snow are we talking about?


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## wombosi (Apr 22, 2008)

tinner666 said:


> It can be done, but matching that siding to widen the exit could be a bear to match.


you lost me with this. what do you mean?


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## wombosi (Apr 22, 2008)

tinner666 said:


> How much snow are we talking about?


well, had 2+ feet last week.
whatever accumulates basically stays in the valley.


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## tinner666 (Mar 14, 2005)

Lot of snow. Irrelevant now, but did you know that the person who did that valley before really screwed the pooch? That 'weave' is so wrong, it's directing lots of water under the shingles. The courses were supposed to meet in the center, not 1'-2' up the steep side.


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## tinner666 (Mar 14, 2005)

Here's what I'm talking about, though the scale and final location may need to be adjusted. And I suggest investing in some heat tape so there is no accumalation there.


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## wombosi (Apr 22, 2008)

here's the progress guys:
right click to open in new tab/window and view full size.









i can tell you that slope on the right is ultra steep. put some hair on my chest, that one did. makes the 12" pitch on the left feel like the tits.

here's the valley flashing:









any suggestions for how to proceed at the corner? i'm thinking another large piece of copper that's hooked into the lip of this piece, then start step flashing about 12" up from the corner and leave the corner area exposed copper.
i have the piece and was trying to fabricate it by hand. looks ugly but i think it will work and can't be seen from the ground.

or should i just start step flashing at the corner?


thanks for all the suggestions.


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## tinner666 (Mar 14, 2005)

What was the reason for a W valley when that pitch requires a channeled valley? ( I assume some roofer made that for you. The one extra break and 5 second to make it would do wonders there.)
A 'W' is great when the slopes are the same. Worthless on that type.

The last pic shows a piece of W for comparison. Water won't cross a channeled valley. I assume it's too late to change?


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## tinner666 (Mar 14, 2005)

I believe I owe you an apology. 
I said; "What was the reason for a W valley when that pitch requires a channeled valley? ( I assume some roofer made that for you. The one extra break and 5 second to make it would do wonders there.)"

I feel I came off harsh, and or wrong. The comment, if I put =it right this time is directed towards a roofer. I believe you are a DIY'er and a roofer advised you to use the 'W'. You wouldn't know any better, but any roofer worth his salt would know the difference since the channeled valleys have been around since before the US was settled, and worked before I&W and other super underlays. 
Anyway, if I sounded like I was taking you to task or anything else, I apologize. It wasn't meant that way at all. And if so, I'd rather apologize in public instead of PM.

I hope the link was helpful.


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## tinner666 (Mar 14, 2005)

I can't make out much corner detail from your pix. The lower valley has to terminate 12" or so above the corner. Then the from of dormer shingles, then the term flashing. The upper section comes down and across all that about 12" and must not be cut. THe tinner's wing formed by coming around the corner will get trimmed as the siding and trim work go on.


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## Michael Thomas (Jan 27, 2008)

IMO, in the best of all possible worlds that would be a field fabricated channeled valley that extended up the side of the dormer and was integral with the apron flashing at the bottom of the dormer.

It's tricky to find roofers who can do this kind of sheet metal feild fabrication, but it can be done, here's an example I saw recently.

Not a valley flashing, but it gives an idea of the complexity of the shapes they can be fabricated by a roofer who knows how to do this kind of work.


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## bcdemon (Jul 12, 2010)

I say "W" or channeled valley metal, run it up the side of your dormer 6" or more. The water will run so fast down that 14/12 slope it will get under anything. But metal :thumbsup:


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