Strange folded edge on new conservatory roof flashing

[karatekaren]

We have just had a new roof added to the conservatory. It seems like a good job. The only odd thing is where the flashing overlaps it has been deliberately folded into a triangle which seems to expose the tiles underneath. We have asked and they say it is deliberate but have given no explanation. We thing there should be more of an overlap to prevent moisture. These are light roof tiles. I have added a picture. It is the same for both joins. Can anyone explain? 

Edited October 14 by karatekaren
Spelling

[Marvin]

Don't know why there is the triangle.

 

Each lead sheet along the joint should be no longer than 1.5 metres. If the lead is cut any longer it could lead to splitting of the lead work due to expansion and contraction. When fitting flashings they should overlap by a minimum of 100mm.

 

Good luck

 

Marvin

[karatekaren]

Thanks Marvin. The overlap is definitely not that much. I appreciate your answer. Is that the same for all type of tiles? These are lightweight as on a conservatory. 

[Marvin]

Hi @karatekaren

 

Actually looking at the picture again I realise it's an abutment flashing

 

An abutment flashing is used to bridge the void where roof sheets meet a vertical wall, to provide a weathertight seal. What is the reccomended overlap of adjoining abutment flashings? The minimum ovelap of adjoining abutment flashings should be 150mm.

 

 

Edited October 14 by Marvin
spelling error

[Marvin]

It's not the tiles that decide the overlap but the possibility of water being able to run underneath the overlap. Abutments can cause a wind funnel and therefore if it rains the wind can force the rain up the join!