If the ice and water shield is missing then you will have to remove the shingles on both sides along the valley put ice and water shield in place and re shingle the roof.
Tile roof valley repair.
At precision slate and tile roofing we always offer the most professional roofing repair services.
This video shows the traditional and best way to repair a lead valley on a roof.
Step 4 fix a crack.
In order to remove the debris so that there is no more leakage you will need to remove the tiles from the valley clean out the area and then reinstall the tile.
The best way to do this is to install new metal flashing.
Always get a professional roofing contractor who has experience with all types of roofing materials to inspect and repair your roof.
Basic roof valley repair for a temporary repair you may be able to use roofing cement to mend any cracks or leaks.
But as mentioned this is only a short term solution and you ll eventually need to construct a new roof valley.
Consider converting the roof valleys into open ones to avoid debris collection in the future.
More often than not this can cause leaks in clay roof tiles.
A properly flashed roof valley should have an ice and water shield installed with roofing felt being properly secured over the ice and water.