How to locate leak in roof valley and repair it?

newhomeowner2026

Hi guys…

Need some advice

House was built in 1994 and I had the roof valley replaced about 11 months ago. At the time, I asked the roofer about the gaps between the roof valley and the tiles and whether we needed something like Stormseal or another type of sealing. He said no and that nowadays it’s better to leave it open.

Recently, I started noticing some minor cracks, so I decided to get into the roof cavity and took these photos.

It seems to me that water may be leaking from the valley onto the timber. So far, I haven’t noticed any marks on the internal ceilings that would suggest an active leak. However, based on the colour of the timber, it does look like there may have been some water exposure.

1. Is there any way to confirm whether the water is coming from the roof valley, particularly after the recent six-day rain event in Melbourne?
   2. If it is coming from the valley, how should this be properly fixed?

Thanks heaps

JacobZ

Welcome to the Bunnings Workshop community, @newhomeowner2026. It is wonderful to have you with us.

Firstly, if you are working in your ceiling cavity, it is always best to isolate the electricity at your switchboard as there is potential to come into contact with live wires in your ceiling cavity. It is not worth the risk, regardless of how confident you feel. Stay safe, switch it off.

From the photos, the timber does look like it has been exposed to moisture at some stage, although it doesn’t appear to be actively wet or rotten. I’d suggest checking the affected timber for any softness or deterioration. This can be done by poking the timber with a screwdriver or similar tool. If you do find rot, it would be worth having a builder assess it given the structural nature of the roof framing.

The truth is, confirming exactly where water is entering can be very difficult because it can track along framing for quite some distance before reaching the point where it becomes obvious. As an initial check, you could have someone spray the roof around the valley with a garden hose while you watch from inside the roof cavity for any water ingress. Just avoid getting onto the roof itself, particularly while it is wet. If you can see water entering, then this can give you an idea of the entry point, which can then guide the approach to fixing it.

Ultimately though, a roofing plumber would be best placed to carry out a leak inspection and check the valley, tiles and surrounding flashing. If they identify the valley as the source, they can also advise on the correct repair rather than adding sealant without first confirming the cause.

Allow me to tag @Nailbag and @Dave-1 to see if they have any thoughts.

Let me know what you think.

Jacob