Hello,

Recently, I removed shingles on my garage roof so I could apply ice&water shield where the roof-line abuts the sidewall of the house. I applied the ice&water shield so there is around 10 inches on the roof deck and 10 inches on the sidewall.

Now, I have a leak. Recently, we experienced several days of extremely cold weather and a lot snow, then, quickly, the temperatures climbed into the 50's, so the snow has been melting quickly. That's when the leak started.

I have attached two pictures; one from the inside of the garage and one from the outside.
From the inside, you can see the sheathing spacer. That's where the drips were coming from.
From the outside, you can see a pink rubber band in approximately the same area as where the leak is seen.
Note: I removed the last bit of snow in the area where you can see the exposed shingles. After I removed that snow, the leak stopped.

The Ice&water that I applied went up the deck and sidewall as far as the base of the valley where the house's roof-line dives into the garage's roof. I suspect that the intersection at the base of the valley is where the leak is. I suspect that the melting ice caused water to back up under shingles.

Do you have any suggestions as to how to pinpoint where the leak is? How should I fix it; tar it up or remove and re-apply?

Thanks in advance.

 

That's an ice dam, where water backs up and runs uphill in places where the ice is blocking the drainage. In all likelihood the leak comes from not putting down the underlayment (felt paper) according to the mfg instructions... which specify the felt paper be lapped about 19" on slopes between 2:12 and 4:12. (In ice dam prone areas, higher slopes benefit from it too even though the mfg doesn't specify it.)

Plus that entire wall would best have step flashing top to bottom, not a continuous flashing. (6x8 step flashing, not 5x7) Water runs off continuous flashing after a few feet, especially if there is an ice dam.

Also, having a roof come down backwards onto an opposite slope is a troublesome design. The intersection of that roof needs ice and water too, and if there is a valley around that corner, it needed it too.

My guess is that it's way harder to fix all these things after the fact than it would be to have done everything perfectly from the start. But yes, removing and reapplying so that everything cam be lapped properly is in order.

 

I agree with XSleeper. It appears there is a valley to the left of the pink ribbon. If the valley has no slope for drainage, water can puddle and get underneath the shingles(source for a leak). An ice dam in the valley multiplies the problem because it makes the puddles higher before they can drain.

 

Thanks @XSleeper & @beezlebob,

I found this picture from one of my previous threads (https://www.doityourself.com/forum/r...oof-lines.html).
The perspective in the picture is from the North side of the house. I'm currently working in the South side of the house, but the way the roof-lines converge is identical.

There is ice&water in the valley to the left (installed by the roofers when the house was shingled 10+ years ago). The only thing I disturbed at that intersection is on the roof-deck where those lines converge.

BTW. That is 8x8 step flashing going up that sidewall.

Thanks again!

 

How high did you remove shingles above the bottom of the valley when you installed the ice/water shield? I assume you didn't re-roof this side of the garage but only removed the shingles, butting against house wall, to the first or second break. How did you seal the top edge of the top shingles replaced since they usually have to be shortened due to hitting the nails in the shingle above? Out of curiosity, how much space was there between the house rear roof and garage front roof before your addition? It looks like they share the same wall.

 

@beezlebob, referring to the picture with the pink rubber band, I removed shingles up to and including the course just above the pink rubber band.
Correct, I just removed shingles butting against the side of the house. I removed a minimum of 12" and staggered the seams.
Yes, at the very top it was difficult to remove nails from the courses above without ripping the shingles. I did use roofing cement under the shingles that I pushed up under the course above it.
The back of the house does share a wall with the front of the garage.

 

In my opinion, you did not go high enough with the ice/water shield. The snow buildup where the 2 valleys converge can be well above the shingle row one row above the rubber band (possible source of leak). My suggestion, weather permitting, is to seal the bottom of each shingle (1/2 inch from the bottom edge) for a 1 foot radius centered at the valley's convergence. In the meantime, if the leak is not tolerable, clean the snow from the area after each snowstorm until weather improves to allow sealing.

 

Thanks @beezlebob
I think you're right about needing to go up higher with the ice&water shield.
The reasons I didn't were because there wasn't any there to begin with--just felt. The original roofers did have ice&water in the valleys, but that stopped when the valleys converged at the deck. I also stopped where I did, because, from that point, the shingles on the garage roof deck start extending into the valleys. I'm afraid I may have to bite the bullet and re-shingle the entire hip roof.
It has been a real PITA patching that roof; it's difficult to remove shingles without tearing them and the shingles on the roof are the old 1'x3' size. I can only get the newer 13.25" x 39" shingles now, so the keyways don't line up.

Question; if you were to redesign that hip roof, what would you do to reduce areas prone to damming?

 

I need clarification. You say the roof shingles are 10+ years old. Does this include the house,garage and breezeway (I thought was new construction)? Why were you adding the ice/water shield where the garage roof meets the house wall after 10+ years?. To answer your question in the previous post, the crotch design is good and I probably would have built it the same way. I have another idea on preventing snow/ice buildup where the valleys converge. Place some heat tape in the valleys (must be placed so water easily flows unto the garage roof) and power it after snow storms until there is no buildup at the convergence.

 

Good question @beelzebob
I have been re-siding my house (for far too long now). I've been tearing off the old cedar shingles, removing the crappy Homasote sheathing and replacing it with 1/2" plywood, and replacing thin fiberglass insulation with Roxul.
The entire house and garage were re-shingled at the same time.
When I replaced the Homasote in the area we're talking about, there was no ice&water where the garage deck abuts the sidewall of the house (probably would not have stuck to that Homasote very well).

I'll look into the heat tape.

Thanks.