Felt lined gulley in valley/butterfly roof

[JoolsUK]

I have a valley/butterfly roof with a felt lined central gutter (pictured below).

The gutter relies on a bitumen mastic seal between the felt and the lowest tiles. Pretty predictably, this keeps failing. In heavy rain, water rises above the level of the first tile and water ingresses into the roof space.

I KNOW that the ideal solution is to lift the tiles to 2-3 levels up, relay the felt valley to that higher and wider level and then re-site the tiles over the new roof felt. But I think this is beyond my skill set and getting a tradesman in London to come and do this is proving impossible presently.

The felt is also bubbling a little and I have filled one small hole with acrylic roofing compound today. Whilst buying the acrylic I see that one can also now buy an acrylic mesh to stabilise old felt by painting acrylic onto the mesh in situ.

I am wondering if a I can implement a temporary solution by bonding mesh to the felt valley floor and then training it up over the first tile on each side (please see my pencil drawn diagram below) so as to create a new and deeper gulley ?

Any comments or solutions would be most welcome

 

[noseall]

Trouble is, any water leaking onto the felt underlay will just find a way back into the building unless you strip it back and deal with the underlay properly. It looks bodged anyway to me.

 

[JoolsUK]

Yes thank you. As I said in my intro, I KNOW the relaying of felt is the ultimate solution. But that isn't possible right now. As I said what I am looking for is a temporary solution. I know the original workmanship is bodged. but knowing that doesn't help me much right now.

 

[datarebal]

The gunk slapped on already doesn't stop water going between the slate bond . So what you have is pointless

 

[JoolsUK]

Thank you. With the greatest of respect, as I said I am looking for a temporary solution rather than being told something that I already know : that the existing arrangement is far from optimal. Thank you anyway.

 

[datarebal]

You don't know the issue . You think you do

 

[JoolsUK]

Actually the slate bond does hold just fine. The problem is as I have stated in my intro. If what you said was true, the roof would leak with every rainfall. But it doesn't, only in a heavy downpour. Thanks anyway.

 

[datarebal]

Not so

 

[catlad]

All you will end up doing is putting the cost of the work up when someone comes to do it correctly.