On 21 Dec, 11:28, Harry Bloomfield
wrote:
Rick Hughes formulated the question :

"jim" wrote in message
...
We've had 3 large velux installed above each other up the slope of the
roof above a new staircase.

you would need at least 100mm overlap for a flashing, 150mm ideally.

I have just checked mine, which I put in 20 years ago. It has 100mm
overlap, and I can see a minimum of two layers at all points in the
flashing.

--
Regards,
Harry (M1BYT) (L)http://www.ukradioamateur.co.uk

hi thanks for thoughts - when you say "two layers" what are those two
layers of?
Presumably velux flashing (from the kit) around the window and what's
the other layer? felt, lead,....?

cheers
jim