Unequal Rafter Height

[FarmerJohn]

Hi,
I have stripped out a part of my roof that had beed previously fitted with Klober dry valleys, before that they were lead.

These were fitted by a professional roofer about six years ago but have leaked ever since.

I have found that the dry valleys (Klober with centre upstand) were just chucked onto the valley boards (about 25mm thick and nailed ontop of the rafters).

Even worse, when I measure along the valley (at right angles etc), I find that one roof is about 40mm higher than the other side. My plan was to simply remove the valley boards from above the rafters and refit so that they are at rafter height (cutting to length and battens etc).

This I did one side and the dry valley fits that side perfectly, but if I lower the other side I will still have a 40mm height difference which I don't think the dry valley will be able to bridge.

What are my options to resolve this?

If I went back to lead, what would be the minimum depth and width of the channel need to be?

Regards
FarmerJo

 

[FarmerJohn]

Hi,
Managed to resolve the issue after a bit of thinking and a previous answer on the site regarding a similar height difference.

The solution was to move the centre of the gully to the left by about 75mm. This was the actual line where the two roof heights intersected and now the havig lowered the valley boards to rafter height and the move, the Klober dry valleys fit perfectly.

Regards
FarmerJo