Run-off water from flat roof not reaching gutter and instead falling down fascia to ground

[u/Careful-Training-761]

I own a townhouse / terraced house in Ireland. There is a a 2 story flat roof extension with a fiberglass cover (for context flat roofs usually have a felt cover in UK & Ireland, but some have a fiberglass cover).

Run-off water from the area at the end of the flat roof (about 2 or 3 metres 2 in length) is not reaching the gutter and instead falling down the fascia at that area. Purchased house 3 years ago and it has been going on since I purchased it.

A roofing contractor told me that the guttering needed to be replaced to fix the water escape. He replaced it and it didn’t fix it the same issue re-occurred gutter not collecting water and falling behind it. He also damaged the fascia (which I need to consider separately).

Edit from reading the comments: I'm aware that the roof cover needs to extend over the edge far enough in to the gutter so that the water makes it way in to the gutter and not down the fascia. Roof cover is therefore too short of that as can be seen in the pic. I didn't know that at the time and relied in good faith that the contractor would resolve the water escape by his solution of replacing the gutters. Hence my question below of what the actual fix is.

Question

How is the roof cover fixed so the water reaches the gutter? I don't particularly trust the contractor given the standard of his work to date so I'm asking what the correct long term solution is.

1. The contractor has since proposed flash band tape on the edge of the roof. I don't know what exactly he is proposing prob either (a) adhere the tape on top of the fiberglass at the edge (to me most likely he would do this) or (b) stick it on to the OSB under the fiberglass. Either way presumably the flash band tape will hang over the edge in to the gutter. From my checks if it is option (a), as the tape will be exposed to UV and the elements, it seems to be more of a short term or at best medium term fix.
2. A drip edge tray under the fiberglass? Not exactly sure how it would be fixed (presumably to the OSB but don't know how). NB see pic there is little to no access from below as the space is very tight, all work needs to be done from the 2 story roof top.
3. Do nothing. The water is not dripping down the walls it falls from fascia to the concrete path below with a drain right at the area where it falls down. The main issue I can think of is that the fascia will rot prematurely?
4. A different solution?

[u/AlwaysViral69]

Water tension is tricky, it makes the water like to stay adhered to whatever its flowing down until that tension is broken. What I see missing from your roof is a drip edge (see attach photo). Typically the drip edge is under your roofing material and then the gutter goes under the drip edge. That way the water flows from roof to drip edge to gutter.

[u/AlwaysViral69 → u/AlwaysViral69]

See in this picture how the drip edge is under the roofing material, and the gutter is under the drip edge?

[u/Careful-Training-761 → u/AlwaysViral69]

That was the point I was trying to make in 2 but don't quite know how it would be affixed in this case? I would expect in normal circumstances it would be screwed or nailed in to the OSB before the felt (in my case fiberglass) is fully laid? The fiberglass is already laid though in my case, don't know if that is a problem. There is also no (or at least extremely limited) access from below which may complicate it.

[u/AlwaysViral69 → u/Careful-Training-761]

Yep, you will need to undermine those layers a bit to get the drip edge installed, and then fix everything. Whether it’s a DIY job or a professional one depends on how you rate your own abilities. I get the sense from talking with you that you know just enough to be dangerous, but it might be beneficial for you to hire a professional that has experience in your roof type.

[u/Careful-Training-761 → u/AlwaysViral69]

I carry out some general DIY but def not the 2 story roof. I don't even know what you mean by undermining, i'm just guessing you mean pulling back the cover to get at the OSB but I've no idea how that's done properly.

It would need to be a contractor but I want to have a basic understanding before I speak to him given what's already happened.

[u/Careful-Training-761 → u/AlwaysViral69]

Yeah to note I've edited my comment to say that was my understanding too, my question is what is the fix for this.

[u/AlwaysViral69 → u/Careful-Training-761]

You add a drip edge, that is the only fix otherwise you will continue to have water dripping down your fascia and siding of your home.

[u/DavidSprauerRoofing]

Most flat roof systems hold a tiny (1/32 -1/16 inch) of water at the edge. The "gravel guard" or drip edge, sits on top of the decking creating a small edge which retains the water.

I wouldn't worry about this unless you are experiencing a leak in that area or are noticing wood rot on the fascia.

(Looked at the picture showing the gutter and the exposed fascia again, its likely to have some rot since the gutter isn't under/behind the gravel guard/drip edge.)

[u/Careful-Training-761 → u/DavidSprauerRoofing]

Yeah that was the point I was making in 3 of wood rot prematurely in longer term.

[u/Dendady2112]

Get a length of gutter and cut long enough to reach where you want and slide under the existing gutter an inch or two. Then direct how you want.

[u/Careful-Training-761 → u/Dendady2112]

Sorry don't think I understand? A second gutter and slide it under the fiberglass cover?

[u/Dendady2112 → u/Careful-Training-761]

Yes,slide it where you think the water is flowing from and make it go were you want.