Ice/weather guard installation question

[Michael Carson]

Lately I have inspected newer construction where the ice/weather guard (underlayment) is installed underneath the drip edge at the eaves. It is my understanding that this is to be installed between the metal edge and deck along the rake and over the metal edge along the eave. Is this correct and when the underlayment is installed underneath the drip edge instead of over what can happen? I called it out in my report and said to consult roofing contractor, etc. I included a picture of the area and a diagram from the illustrated home in my report as well.

Thanks.

[kurt]

It should be wrapped behind the gutter; otherwise, water can still back up under it.

That means the drip edge has to be on top of it, which contradicts several installation "requirements" in my local codes.

I think this came about from the requirement for roofing felt to overlay the drip edge, which makes sense.

It does not make sense to stop the IWS at the eave edge.

[hausdok]

http://www.na.graceconstruction.com/cus ... L-061C.pdf

ONE TEAM - ONE FIGHT!!!

Mike

[RobC]

I like to see the drip edge installed on the sheathing first and the eave protection on top of it, shingle style if you will. This way, it can direct water in the gutter system more effectively than if it's on top.

Being on top is not totally wrong but in the event of an ice dam condition it wouldn't be as effective.

Edited to add:

This is what I mean

Download Attachment: RoofingDripEdge (Medium).JPG

92.02 KB

[Michael Carson]

I cannot find anything in my local WI. literature that confirms either way other than it must be 30 inches up from eaves. I did find the installation link above very helpful and saved it to my file, thank you. I looked at 3 references and all read that it should be over the drip edge, I'm confused.

[RobC]

I cannot find anything in my local WI. literature that confirms either way other than it must be 30 inches up from eaves. I did find the installation link above very helpful and saved it to my file, thank you. I looked at 3 references and all read that it should be over the drip edge, I'm confused.

It What?

[Michael Carson]

I like to see the drip edge installed on the sheathing first and the eave protection on top of it, shingle style if you will. This way, it can direct water in the gutter system more effectively than if it's on top.

Being on top is not totally wrong but in the event of an ice dam condition it wouldn't be as effective.

Edited to add:

This is what I mean

Download Attachment: RoofingDripEdge (Medium).JPG

92.02 KB

Thank you for the illustration, that is the one I used in my report. It being underlayment.

Thanks again to everyone for the response.

[hausdok]

Hi,

That illustration is the way that felt is installed but IWS is installed with the drip edge over the top of the IWS. Manufacturer's installation instructions take precedence.

ONE TEAM - ONE FIGHT!!!

Mike

[RobC]

I had to ask because the way our code reads, the eaves protection membrane should extend 12" inside the interior face of the exterior wall.

Problem is you can't get 12" coverage with a 36" roll on a 24" overhang and a 2x6 wall.

Yes, I know about the 44" commercial felt rolls, but I don't seem them very often on residential.

[kurt]

I had to ask because the way our code reads, the eaves protection membrane should extend 12" inside the interior face of the exterior wall.

Problem is you can't get 12" coverage with a 36" roll on a 24" overhang and a 2x6 wall.

Yes, I know about the 44" commercial felt rolls, but I don't seem them very often on residential.

That's why one installs multiple courses on occasion.

Interesting about the link.....no mention of wrapping the IWS behind the gutter, only that the drip edge be over the IWS.

I remember the story of why wrapping the the IWS behind the gutter is important; it was one of those learning experiences.

[RobC]

Grace recommends installing flashing OVER their product!?

In keeping with the logic that water runs downhill I'd have to question the sensibility of trapping water behind the flashing and/or directing water behind the gutter system.

Wrapping the eaves protection behind the troughs is something we don't do here. We want to direct water INSIDE the gutters and not behind them, the drip flashing is an option (not mandated by code) to further aid in the process.

Placing the flashing over the eaves protection or IWS, simply doesn't make any sense.

[kurt]

Well, actually, it makes perfect sense, if one gets all the details correct. You can have water directed into the gutter, you can prevent ice dams backing water up under the felt, and the drip edge is installed over the IWS so as to protect the exposed "break edge" in the membrane.

I've "solved" several otherwise impossible eave ice dam issues with wrapping IWS behind the gutter, and drip edge metal over the IWS and lapped into the gutter.

Of course, folks will do whatever they want, but that's what keeps water out of eaves in ice dam conditions here.

The backstory I mentioned is sort of interesting......

I did a job a few years ago for the fair and just Lisa Madigan, AG for the State of Illinois, fighter of the good fight, may she soon run for governor and expunge the memory of Roddy Boy.........

70mph winds on the day of the inspection. Couldn't get on the main roof due to high wind, stated as much, and told her to have me "come back to inspect the roof, eaves, and gutters at the earliest opportunity" when the wind died down. In the meanwhile, I found a half dozen other things wrong with the cornice returns, and indicated the lack of attention to detail might be found elsewhere "when I came back to inspect the rest of the roof".

She never had me come back. I got called for expert testimony when she took the roofer to task for the flooding conditions in her north wall caused by ice damming. A stream of North America's finest roof experts all stated categorically that the problem was the IWS wasn't wrapped behind the gutters.

I was also informed that she was reasonably pleased with my report, and while disappointed that I hadn't completed a roof inspection, made substantial mention that she felt I had done all the right things, specifically, "telling her to have me come back to inspect at the earliest oppportunity". She indicated that had I not given specific instruction for me to return, i.e., no recommendation or passive stuff, but me telling her what to do, the fair Lisa implied in no uncertain terms that I would have been involved on the other end of the complaint, not as an expert but as a defendant.

So, do it however you want. Me, I'm sticking with the IWS behind the gutter, metal over the IWS and draining into the gutter.

[Tom Raymond]

First of all drip/rake edge isn't flashing, it performs the same function as a shingle molding, it is designed to cover the edge of the sheathing and support the portion of shingle that projects beyond it. Granted, when we started making these things out of metal we designed some water shedding features into them, but they are not flashings. In ice dam country if the ice and water shield is on top of the drip edge, it provides no protection at the point the ice dam starts, by wrapping the IWS over the edge of the sheathing and onto the fascia the protection is extended past the top edge of the gutter where it is needed most. Further more, you do not want to apply any adhesive roofing material to aluminum drip edge, it will curl up the first time it gets cold. Ask me how I know this.

Tom

[Bryan]

The attached PDF is from the Grace web site and addresses one additional method of "stripping in" the drip edge between two layers of IWS. I also seem to remember something about installing the IWS over the eve and into the gutter; however, I can not seem to remember where I read that.

Bryan

Download Attachment: Grace Eve Detail.pdf

387.78 KB

[kurt]

Excellent detail. Same general design as a flat roof eave/gutter/IWS detail. For those that just gotta have the membrane on top of the gutter for shingling, it'd work.

Thanx.

[Bryan]

For what it is worth, Grace has an excellent set of downloads available on their site for the various products they manufacture.

Bryan

[hausdok]

I think some folks are mixing up IWS and underlayment in their heads. IWS is used below the felt and it's the felt that's supposed to overlap the drip; not the IWS.

OT - OF!!!

M.

[kurt]

Exactly. But of course, almost all installations forgo the felt and only have IWS as the first course of underlayment. I can't remember ever having seen IWS, felt, and drip edge.

[Ed the Roofer]

Due to many reports from Roofing Contractors that have in recent years, begun to have to do tear-offs on roofs that have Ice and Water Shield installed, especially the Grace Brand, which is the leader of the pack and the tackiest, a general observation being suggested is to add the felt paper over the Ice and Water Shield, to prevent severe adhesion to the bottom side of the shingles, in the event that a repair of some of the shingles needs to be addressed.

Ed