What are some tools or methods I can purchase to trace a water leak?

Question

A downpour of rain has caused one of the ceilings in my bedroom to leak. Now a small little hole in the ceiling is dripping water.

I would like to get to the bottom of how I can prevent this from happening. The first thing I did was call roofers to determine if there was a hole in my roof somewhere where water was coming down. The first roofer couldn't find any holes so I scheduled 4 more inspections with different companies. They all told me the same thing, "your roof is still new and we were unable to find any holes or causes to the leak."

So then I decided to add some water proof coating on my house, so I purchased a couple thousand dollars worth of silicone coating and coated my roof with it. Unfortunately, when it rains, the leak is still happening.

At this point, I'm beyond frustrated with what is happening. I'm a new homeowner so sadly I'm not too savvy on who to call for stuff like this or best and efficient things to buy to identify the leak. (I thought the roofers would help trace it but they didn't…they couldn't determine it was a roof problem and left). So who do I call then?

One option I had in mind was to tear the ceiling apart and identify the leak from that point of view but I'd like to see if there are any other inexpensive options I have not considered yet.

I also thought it might have been a leaky pipe but the leak only happens when it rains. But a weird thing is that it doesn't always happens when it rains. Which is baffling and hard for me to fathom. I also turned on the upstairs shower and let it run for a bit and no leak happened so it's probably not a leaky pipe.

Any help for things I can try or materials or tools I can purchase to find out exactly where the water is coming from is appreciated!

Answer 1

If four roofers could not find the leak, it's unlikely that we can find it from photos. So I'll tell you what kinds of things to look for, and answer the question, 'what kinds of tools' etc.

If the roof is generally in good shape and there are no obvious holes, water is likely getting in at the interfaces between the roof and walls or pipes. If you can get on the roof, closely examine the flashing around chimneys and pipes for cracks or openings.

Sometimes water will roll off the roof into the gutters, and blocked or overflowing gutters will spill the water back into gaps in the fascia or small failures of the roof material where it meets the gutter. I have had this problem twice in two different houses so I regard it as a high probability. And it's very hard to detect. You need to closely inspect the gutter/roof interface all along its length (Unless it's obviously totally failed, but then hopefully 4 roofers wouldn't have missed it).

To trace the source of the water do not rip open the roof. If anything, buy a cheap borescope. In the USA, $60 to $80 will get you a self-sufficient (does not require a phone) dual camera one with a clear picture. With that you can make small (one-inch) holes in interior walls and see if water is coming (or not) from certain directions. These holes are relatively easy to patch, or just close with plastic grommets.

USe these techniques and if you answer the questions in the comments to your Question, you'll get further advice.

Answer 2

Looking for from on top of a roof can be difficult, since the leak might flow someways before it leaks onto the ceiling.

Usually the best tool is your eyes looking at the bottom of the roof deck, water leaks usually leave stains you can follow to the leak.

There are inspection cameras that only need small holes if getting into the attic is hard or limited space for a person.

Answer 3

Start at the point in the ceiling where it leaks and then trace it backwards from there. Get to the top side of the ceiling from inside the attic. The insulation in that area should be damp. You should be able to trace the leak in a general direction by reaching down through the insulation and feeling whether the bottom layers are damp or dry. I like to fold colored index cards in half to make a little tent shape, and place them on top of the insulation to mark the edges of the damp section.

Once I've outlined the extent of the moisture, I know the water has to be coming down from somewhere in that area. If it's dripping down from above, then you should be able to notice that the top layers of insulation are wet in that area. If none of the top layers are wet, then the water may be coming in from the side. Look for pipes or beams that cross through the wet zone and check for moisture on any of them.

A moisture meter can come in handy for this task. This one from Klein tools works on wood, masonry, and drywall. I'd use something like that to test the entire ceiling from below, then go into the attic and test the underside of the roof decking plus any rafters or beams in the area near the leaky ceiling.

If you find something that you think might be the source of the leak but can't tell for sure, tape some paper towels down in the area and then check them after the next rain storm. Even if they've dried out, their color and texture will change once they've gotten wet. I've taped them to top side of ceiling drywall, wrapped them around pipes, etc. A very cheap solution, but you won't get any data until the leak happens again.