Low pitch metal roof sheets need to be detailed correctly on both ends during installation for it to perform correctly.
The upstream ends get turned up to stop water from running backwards and overflowing the top end of the sheets. The downstream ends gets turned down.
Many roofers do not understand the importance of turning the gutter end of the roofs sheets down. The turn down is needed to stop the water from dribbling backwards along the underside of the roof sheets and ending up where it is not welcomed.
We installed a kliplok colorbond roof recently and the sheets were turned down by my guys with a purpose made ‘turn-down’ tool. Personally, I do not like this tool because it does not turn the sheet down far enough. I prefer to use the purpose made ‘trimdek’ turn-down tool instead and modify the action to suit the wider pan…
…Anyway, the owner experienced leaking behind the gutter and when sent me a video showing exactly what happens when a kliplok roof sheet is not turned down far enough…
Check it out on the You Tube video below:
It also helps if you have the correct tool to do the job….