Hi. I understand that 25mm seams and 3degs fall are standard on zinc roof.
But ... what about with 35mm seams ?
Can you then take it down to 2 degs or 1.4 ?
Is there a way to calculate all this - the flow rate during downpours and pooling ???
I am thinking that instead of 19mm plywood underneath, you just have 9mm.
And then stick another 9mm under between the joists, thereby you save the 1cm which is transfered to higher seams.
Is that genius ?
But ... what about with 35mm seams ?
Can you then take it down to 2 degs or 1.4 ?
Is there a way to calculate all this - the flow rate during downpours and pooling ???
I am thinking that instead of 19mm plywood underneath, you just have 9mm.
And then stick another 9mm under between the joists, thereby you save the 1cm which is transfered to higher seams.
Is that genius ?