How to fix gap between gutter and roof sheet?

quynh_

We have a deck roof (5.5m × 3m). The roof sheetings (mix of colorbond and polycarb) are too short and leave a gap between the sheet edge and gutter, so rain misses the gutter. The roof has a slight slope toward the gutter (timber batten at the back).

We are thinking to slide small sheeting sections under the existing sheets so they overlap into the gutter then re-screw through both.

Someone suggested custom flashing instead. Given the slope already directs water toward the gutter, is overlapping the sheets sufficient, or is flashing genuinely necessary for a weathertight result?

MitchellMc

Welcome to the Bunnings Workshop community @quynh_. It's amazing to have you join us and many thanks for your question on roof sheeting.

Installing short lengths of matching sheeting looks like it would work in this situation. Since the roof already has sufficient fall towards the gutter, the main objective is simply to extend the water path so runoff reaches the gutter rather than undershooting it.

I'd recommend cutting the extension pieces long enough that you can remove the last row of screws, slide the new sections underneath the existing sheets, and then reinstall the screws through both layers. Just not so long that you see the ends of the sheets from beneath. This will help hold the extension pieces securely in place and minimise the chance of movement over time.

While a custom flashing would provide a solution, it may not be necessary if the extensions can be installed with adequate overlap and are secured properly. Given that the roof pitch is already directing water towards the gutter, extending the sheeting should effectively bridge the gap and improve water capture.

Just ensure there's sufficient overlap between the existing sheets and the extensions to prevent water from being driven back underneath during heavy rain or windy conditions.

Please let me know if you have any questions.

Mitchell