Remedial work on houses following a spate of heavy storms down the east coast of Australia in the past 12 months has revealed internal stud and ceiling saturation as a result of water being forced back into roof and wall cavities.
The primary culprits are high fronted gutters that are fixed flush onto the fascia. These gutters have gained popularity over the past 10 years because they hide the ends of roof sheet and tiles from view.
Unfortunately, when the downpipes block, or the gutter reaches its carrying capacity, the overflow point is at the back of the gutter, and can result in the excess water being pushed back into the roof.
The designers of Smartflo gutter were aware of this problem, and created a profile which is 14mm lower at the front than the back. In the event that the gutter reaches its carrying capacity, the overflow will always flow over the front of the gutter.
The AS3500.3, which is the reference standard for roof and gutter drainage, offers several methods by which high fronted gutters might be mounted so as to avoid back flow into the roof cavity, however the clipping mechanism recommended by many of the major roll formers, prevents both the flashing solution and the 10mm gap solution from being implemented.
All the arrangements of the Smartflo gutter from Smartflo Gutters comply with the Building Code of Australia, however the clipping mechanism for many high fronted gutters prevents either of the first two overflow measures, and the third is being avoided because it exposes the ends of the tiles or roof sheet.
Smartflo gutter being broader than conventional gutters, can be lower at the front, and still mask the ends of the roof sheet or tiles.