How to fix a water leak through ceiling light fittings ?

[satishmarathe]

A few weeks back during the rains water started coming through one of the ceiling lights ! 

we immediately shut off the mains and kept them off for a good 12 hrs and then started it up again .

Today I went up to the roof and can see a possible damage / repair work done in the past ( purchased this unit just 6 months back and unfortunately this issue was not identified during purchase due diligence.

Anyways - here is the snap of the roof ( no tiles , seems like tin or some metallic material ) 

You can see some kind of sealant seems to have been applied in the past :

what kind of sealant would you suggest ?

how long does it remain dry ( before it rains again ) to be effective ?

This is in melbourne

[wooshka]

Water leaks through the roof are a  hard issue to fix as the area where the water comes in can be metres away from the area inside, can you take  a photo of a larger area outside so we can get an idea of where the drainage runs. 

The sealing in the photo looks fairly good from what i can see

[MitchellMc]

Welcome to the Bunnings Workshop community @satishmarathe. It's wonderful to have you join us, and many thanks for your question about sealing a leaking roof.

It's great to see that @wooshka is also on the case, and I'd agree that a wider shot of the roof would be helpful.

How heavy were these rains you experienced? If it's anything like what NSW saw, we had water finding its way into areas where they'd been sealed sufficiently for years. In excessive downpours, water that can't escape the roof fast enough will build up and get under the roof sheeting. An area that is not generally sealed. 

If you feel that the water is seeping through the sealant, you can waterproof the entire channel. I'm a fan of products like Crommelin 1L Exterior Grade Brushable Waterproofer. You can use this product and paint it all over the area. This can work much better than sealing a tiny area with silicone sealant. I'd recommend cleaning and then coating that entire corner section and any other areas that look suspicious.

Is there a ceiling cavity? If so, you could run a hose on the roof and check for leaks inside the ceiling.

Please let us know if you have any questions.

Mitchell