If you have leak under a deck, it can get expensive if you don’t know where to start looking!
Is it leaking from directly above, or tracking along beams and dripping off at a low point?
There are different types of decks… over the top of rooms, cantilevered, tiled, butinol etc etc. No matter what type of deck you have, the issue of leaks will usually happen at some point, and sometimes they can be expensive to fix!
So should you get a tiler around to start ripping it apart to find where the water is coming in, or would a thermal imaging inspection make more sense? I can tell you right now that the logical way to go would be to detect the leak source first. It’s cheaper and faster… and will give you a good idea of where to start looking.
Here is a infrared image on leak on a lounge room ceiling that had a deck directly above it…
If you are seeing any suspicious marks on your ceiling under a deck (or on interior walls near a deck), then it could be wise to get an infrared thermal imaging inspection asap… for a piece of mind if anything.