Concealed guttering can regularly overflow water into the eave lining & down through light fixtures, across windows & doors.
Compounding this problem is that downpipes usually connect to the rear side of the gutter & drain above the eave lining & down the wall, thus keeping the “offset” of the downpipe hidden from view. This design is not an effective way to drain water from the gutter in heavy storms.
These are some options which can used to limit the chances of overflowing, including overflow holes made through the gutter & timber fascia & draining the downpipes through the bottom of the gutter with the offset below the eave sheet.
However if you are wanting a fail-safe option we recommend use of our own 1 Piece Concealed Gutter System, developed by Eastside Roofing. This incorporates the front capping & gutter in 1 piece.
Refer to the photographs below, and certainly do not hesitate to contact us if you are interested.