How to find leaks in roof?

CMaco

Whenever we receive a substantial downpour the roof leaks into a bedroom, almost like a tap is running. I myself cannot see where on the roof that it might be coming in from so that I can repair it. There is no ceiling access to see from under the roofline. 

I think it is somewhere near the two different rooflines *See pics. Bedroom is under the lower roofline where the newer sheeting is. 

JacobZ

Hi @CMaco,

Welcome to the Bunnings Workshop community, it is wonderful to have you with us.

Finding the source of a roof leak can be quite difficult. Even more so if there’s no access to the space under the roof to see where the water is getting through. Water doesn’t always appear directly below the entry point; it can travel along roof framing, battens, or insulation before dripping down somewhere else. This can make it challenging to locate the exact source.

When the roof is dry and safe to inspect, start by checking carefully for cracks, gaps, or lifting in the roof sheeting, flashing, and sealant. Look for any loose screws, rusted areas, or places where different materials meet, as these are common entry points for water. If it’s safe to do so, you can also run a controlled water test. Have another person inside while you use a garden hose or buckets of water to wet small sections of the roof one at a time. Start low and move upward slowly, waiting a few minutes between each section to see if any water appears inside. This method can help narrow down the problem area.

If there is also damage to the ceiling in the bedroom that needs to be fixed, it is likely worth removing the ceiling sheet so you can see inside the ceiling cavity. If there is already damage to the ceiling, then it would need to be replaced anyway, so it wouldn't be creating an issue that wasn't already there.

If you’re unable to find the source, it would be best to contact a licensed roofing professional. They can safely access the roof and use tools like moisture meters or thermal imaging cameras to detect leaks that aren’t visible from the outside. If you notice any areas that look suspicious during your own inspection, mark them clearly so you can point them out to the professional when they attend. This can save time and help focus the repair work on likely problem spots.

As there could be further damage to the roof, it is likely best to have it inspected by a professional, regardless of whether you can find and patch the leak or not. It's all well and good to fix the source of the leak if you can locate it, but ignoring the unseen damage that it might have caused is not advisable.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob