Building leaks are annoying and can be extremely frustrating particularly if they (as usual ) are hard to find. Recently I found a cause of roof leak on a multi million dollar penthouse apartment in a few minutes (after owners spent $16,000 on repairs that failed to stop leaks).  Thermal imaging camera is particularly useful because it can pinpoint leaks that are otherwise invisible. Sometimes it will bring unexpected findings:

So, if you have persistent hard to find leaks you have the option of forensic scan with thermal  imaging. You will never know what could be discovered.