Velux flashing question (slate roof)

[aa44]

Can anyone help me with a Velux flashing question?

I am trying to install a Velux GPL (top opening) above a GIL fixed element. The windows are installed on the roof and I have been installing the flashing kit today.

The problem I have got is that when I come to install the drainage channel between the two windows, the channel seems to be about 20mm higher than it should be. The "end plates" of the drainage channel are sitting on the flat part of the soakers (which have the funny shaped cut out in them to allow the drainage channel to fit), so it seems as if the soakers would have to be way lower to allow the drainage channel to fit.
It is almost as if the soakers would have to be under all the slates at the level of the battens rather than interleaved with the slates in order to get them down to a height where the drainage channel would fit.

Anybody come across this problem?

Thanks very much.
Andrew

PS If this is in the wrong section then please feel free to move it.

 

[datarebal]

are the slates straight on the board or is the roof battened?

 

[aa44]

The slates are actually straight on to the boards but as far as I can see this doesn't make any difference. Sarking boards are effectively just like extra wide battens. I spoke to Velux yesterday and the answer is that where the soakers pass the sides of the drainage channel, they have to be under all the slates. Effectively you make a longer soaker by putting two of them together and run that under the slates past the end of the drainage channel. The bottom of this soaker comes out on top of a slate as normal.

I did that yesterday and it fits OK now.

 

[datarebal]

Sounds wrong to me, The soakers should be between the slates not under them.
where did you screw the fixing brackets on the deck or on a batten ?

any way alls well ..

 

[aa44]

The fixing brackets are screwed onto the sarking boards, i.e. the deck. A mate who is a builder came round to check that I had installed the window correctly and confirmed that it is.

I agree that it sounds wrong but the installation instructions actually show it that way (when you look at them long enough!).

Thanks for your replies.