Velux leaking

[muymalestado]

We have had great service over 25 years from 6 Velux roof lights BUT now one has a leak in one lower corner. I wonder who else may have had & solved a leak.

It is difficult to discuss because of the technique they use to build these, but I have used clear sealant all round the actual window glass, I have used same at lower end of aluminium rail running down each side.

I can see the drips coming off a draught-proofing strip which runs/is channelled horizontally along the lower end of the wooden window frame

- not the outside casing.

I cannot where this water in entering the window system.

Any clues ?

Thanks

[Kipper at sea]

Check the flashing around the outer frame and under the tiles for pinholes and dirt that as blocked the water channels. Also, check the back gutter for pinholes and any signs of ware. The flashings and back gutters are made of alloy and tend to corrode.