Roof Flashing

Grumpy_chap

We have some flashing that has come loose on our loft conversion dormer as per the photo below.  This was originally built about 14 or 15 years ago.

We already paid to have it repaired once this year, and it has come loose again.  The roofer that repaired it gave all the deep intake of breath and statements that the roof had never been constructed properly in the first place.  

I just wondered whether we actually need this flashing or could just simply take it down.  What does it really do? 
The plastic fascia overlaps the tiles so would it still be sufficiently weathertight if we simply took the flashing out?

stuart45

The fascia has to overlap the top of the tile on the course below the top one. It's called the headlap. On double lap tiles there is always a minimum of 2 tiles at any point on the roof. The fascia must be a bit short on that side, so the flashing makes the headlap. You should have a membrane under the tiles, so probably not leaking.

Grumpy_chap

The flashing does not seem to have ever been fixed (tacked / nailed / screwed) in place so must have just stayed up there by magic?

I think you are saying that if I take the flashing down, or let it fall down, it won't really matter and I can just do without.

travis-powers

Grumpy_chap said:

The flashing does not seem to have ever been fixed (tacked / nailed / screwed) in place so must have just stayed up there by magic?

I think you are saying that if I take the flashing down, or let it fall down, it won't really matter and I can just do without.

It one of those situations where it wasn’t fitted properly in the first place but to refit would mean removing the fascia which in turn would effect the roof covering above etc, it’s a shame as it looks like a good job.
 Where the flashing has fell can you see nail holes in the tiles?

stuart45

double lap tile details - Bing
If you look at the diagram, think of the top slate as the fascia board. On a wall the headlap needs to be a min of 35mm. A roof needs more. My guess is that the fascia is short of making the headlap on that side so it's possible for water to seep through at the top between the tiles. The membrane under the tiles should stop water entering inside, but ideally it's better for it not to get through. The lead flashing probably makes the headlap on that side. On the front the fascia probably does it.

Grumpy_chap

travis-powers said:

 Where the flashing has fell can you see nail holes in the tiles?

No, there are none.  
The roofer that "fixed" it earlier this summer said that there were no fixing holes and unclear how it had been held in situ.

stuart45 said:

double lap tile details - Bing
 The lead flashing probably makes the headlap on that side. On the front the fascia probably does it.

I think I can see looking closely that the bottom of the flashing on the side is about the same level as the fascia on the front.

stuart45

The problem is fixing the lead, so it stays in place. I guess it was wedged in place with some lead wedges.

Grenage

I can't see how you'd properly fix it without removing that section of fascia.  I'd agree with the above that it's probably needed to be sure of weatherproofing.

plumb1_2

stuart45 said:

double lap tile details - Bing
If you look at the diagram, think of the top slate as the fascia board. On a wall the headlap needs to be a min of 35mm. A roof needs more. My guess is that the fascia is short of making the headlap on that side so it's possible for water to seep through at the top between the tiles. The membrane under the tiles should stop water entering inside, but ideally it's better for it not to get through. The lead flashing probably makes the headlap on that side. On the front the fascia probably does it.

As above, but also you can get the wind blowing rain up, best if the lead is put back.
recon the facia will come away at the bottom and hook some stainless steel straps/hooks in to carry the lead