Leaking roof around the lead flashing

I think its called the lead flashing, but the sheet of lead strip that is partly in the wall and then bent down to guide water run off.
On a flat roof garage conversion, it seems I have some small leaks at some parts of this flashing where one part joins the next along the roof adjoining the house.
Looks like the builder has used some type of sealant on the joins, but some water is getting through. Not much, but enough to start to leave small stains on the ceiling.

What can I do to solve this? Some sort of sealing paint or something like PVA glue? This part of the garage roof gets a lot of sun so it needs to be something that wont crack.

If you don't get a roofer too repair it you could try seal it with silicone but it may not fix the problem.

If its old it often cracks over times, especially if its one long continuous lengths.

AndroidMan said:

it seems I have some small leaks at some parts of this flashing where one part joins the next along the roof adjoining the house.

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There may be points where the overlap between the two lengths of lead is not sufficient and so water, especially in windy weather, gets blown into the gap and hence the small leaks.

Yes.. its likely a small leak in certain weather conditions.
But my question is what can I seal this non obvious leak with?
Some sort of glue or tar type stuff?
It is fine if it is a messy job, the area in question is not visible from the ground, so something i can just slap on with a big brush would be fine.
Would silicone dry out and crack over time?

AndroidMan said:

But my question is what can I seal this non obvious leak with?
Some sort of glue or tar type stuff?

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We had what sounds like a similar leak in a previous house. I got some stuff in the hardware shop - unfortunately I cannot remember the name of it. It came in a large tub - like a 10ltr paint. It was black and had a consistency like thick gluey paint. It was too thick to "paint" on as such. I smathered it on liberally and worked it in with a brush. Although I had an idea where the leak was I was not certain so I covered a good area. When it dried (quite slowly, I recall) it formed something like a thick film which was rubbery to touch. It was not pretty but, like yours, it was not in an exposed position. Anyway, it stopped the leak. We moved house about 4 years later and there were no further problems in that time at least.

It was a messy job, as you say, but not difficult - the location helped as I was not worried about the aesthetics of the finish.

Edit: I don't think it was either of these specific products I found in the shop at the time but it was along these lines:

Have a look at gorilla glue sealant perhaps

@Early Riser - Exactly what I was after.. thanks!!

AndroidMan said:

It is fine if it is a messy job, the area in question is not visible from the ground, so something i can just slap on with a big brush would be fine.

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Don't just "slap" it on. Read the instructions and I think you'll find that it says to build it up in layers. However, if the lead is not overlapping sufficiently I would replace one of the lead strips or else use an adhesive patch type product to cover those areas where the lead is not overlapping enough.

@AndroidMan

I used something like this for a flat roof seal and then coated the area in "Thompsons Roof seal paint", which would be similar to @Early Riser recommendations.
After a year or so, just checked it again & re-applied the roof seal paint - it was exposed to wind/rain/sun, so I felt best to freshen it up each year.

AndroidMan said:

@Early Riser - Exactly what I was after.. thanks!!

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Have used the products and they're ok, but at some stage the chimney "will need new flashing" and not an every other year cover up.