new extension recurring roof leak

[masamune]

Yes, it seems to be on average above 100mm, except from the top tile which is around 100mm

https://www.dropbox.com/sh/h5h1zkbo...VQ3lha?dl=0&preview=20201110_152331_combo.jpg

 

[catlad]

Look like marley ludlow which are 22.5° min

 

[Celeronmanuk]

Look like marley ludlow which are 22.5° min

That is a good point.

 

[masamune]

Look like marley ludlow which are 22.5° min

The tiles are Redland 49, 100%. Sorry if this wasn't clear from the previous posts.

We tested with a hosepipe and the winner is.....datarebal. Water seeps in under the top tile of the verge and runs down below, dripping into the roof. The tile was also detached from the mortar as in the pics. The give away was directionality of the rain causing leaks intermittently, when it was hitting the verge on the side.

They removed and refitted all verge tiles with new mix. The membrane below, although fixed on the edges, it was sagging a bit further in. It was not wet but it should have been stretched out when originally fixed under the battens.

Fingers crossed, can't believe I'm saying that but wish for torrential rain to test!

 

[catlad]

Glad you have found the issue. Interesting that redland claim 5 more degrees of waterproofing than marley with the same tile profile!

 

[datarebal]

The underlay should have a slight sag. The detail you show we would have had a lead flashing from under the undercloak turned up on the inside. That way if the verge cracks you will not get a repeat