Best way to repair roof valley and damaged top tiles

[RookieDIYER]

Hi,


I’m looking for some advice from roofers rather than posting this as a job at this stage.


I have attached a photo of the roof. The issue seems to be around the roof valley where the two roof sections meet. From ground level it looks like the top layer / tiles around the valley may be worn, loose, damaged or missing in places. There is also moss and general weathering around that area.


Could you advise what the proper repair options would usually be for this type of roof?


For example, would this normally be:

1. Replacing only the damaged or slipped tiles
2. Repairing or rebedding the valley area with mortar
3. Stripping back the tiles around the valley and relaying it properly
4. Installing or replacing the valley tray / dry valley system
5. Something more substantial if the felt, battens or valley underneath have failed

I’m trying to understand what would be considered a proper long-term repair rather than a quick patch that fails again after a bit of classic British rain.

Also, roughly what sort of cost range would you expect for each option in London, assuming normal access and no scaffolding issues? I appreciate no one can give an exact quote from a photo, but a rough ballpark would be very helpful.


Thanks