Roof leaking below Velux

[catlad]

Once you start using mastic then you are admitting defeat!
If you where planning on changing the windows then it would have been wise to add a few course of brick to gain some pitch.

 

[Happyunited]

There's a cracked tile to the left of the highlighted tile.

what tile is that?

 

[Alastairreid]

what tile is that?

 

[noseall]

Eyes like a shi thouse rat!

 

[Happyunited]

View attachment 226555

thank you. The small cut tile underneath?

 

[Alastairreid]

thank you. The small cut tile underneath?

The tile below the cut looks fractured.

 

[Happyunited]

The tile below the cut looks fractured.

just checked, it’s fine just a line of dirt.

 

[Happyunited]

I think I got the pitch wrong. Seems it's OK at 22.6 deg. I spoke to roof tile supplier and they confirmed those tiles are 17.5 dwg minimum. Can anyone confirm it's 22.6? thank you (still doesn't fix my leak)

 

[catlad]

Yes I get 22 degrees.

 

[SpecialK]

What is this?

 

[noseall]

I think I got the pitch wrong.

Correct.

I get your roof at about 16.3 degrees.

In your image, you have the rise measurement completely wrong in relation to the going or horizontal.

 

[noseall]

Yes I get 22 degrees.

According to his rise measurement, yes. Have a look again

 

[Happyunited]

Correct.

I get your roof at about 16.3 degrees.

In your image, you have the rise measurement completely wrong in relation to the going or horizontal.

What bit have I got wrong?

builder has come round. He lifted about a dozen tiles and it was dry under there. I could see the stain on the felt where it has leaked. He was a bit puzzled but replaced a couple of tiles a tightening them all up. It hasn’t poured down since yesterday so I’ve no way to checking, I’m not too hopeful.

 

[datarebal]

If I had to guess from the picture I would have said 15 but not less.
Looking at the measurements the rise is indeed wrong

 

[noseall]

What bit have I got wrong?

Your vertical line needed to stop short of the fascia by about 1 course of bricks based on your horizontal (3m). For some reason you carried it on past that and up to the top of the tiles - therefore you should have extended the horizontal line so that it would meet a diagonal drawn say skimming the tops of your dry verge caps.