We warranty the work, not the leak unless you are doing a full tear-out and replacement. Roof leaks and chimney leaks both can come from multiple areas. Typically we are only hired to repair one of many possible potential leak areas, usually the most obvious or the one in most need of repair. In most cases, this is all that is needed and typically will stop the leak. In rear cases, we do have to come back and do additional work to try and stop the leak which therefore incurs additional costs. Usually, we try to look at it as a phase one, phase two solution. Phase one is repairing the most obvious and easiest to determine problem areas. Phase two, if needed, is to come back and start looking at and repairing the less obvious areas. Either way, we will come back and continue to help till the leak is found, solved and resolved. If a full tear out and replacement is done, then we can warranty the work. If a partial repair or patchwork is done, then we can still warranty our work, but not the leak.