Roof to gutter overhang formula

Mar 07, 2023 1 Replies

I'm replacing my crappy plastic car port pitched roof with PVC covered steel box section but am unsure what the correct overhang (ie horizontal overlap) distance above a gutter should be (to stop run-off overshooting the gutter)? The roof is about 25 degrees and about 4 metres wide.



Thanks in advance.


In message snipped-for-privacy@googlegroups.com, " snipped-for-privacy@gmail.com" snipped-for-privacy@gmail.com writes

Ha! I got overshoot with a 12.5 degree slope and a 6" gutter!

The problem seemed to be caused by droplets gathering on the shallow slope and then being collected into a fast moving spurt!

Luckily I had access to lengths of L shaped galvanised steel. Painted to match the roof and fixed to direct the spurts into the gutter.

Why not do a test? Loose fix a length of roof, apply water and see what happens. You could use 6" gutter if 4" gives problems.

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