Joined: July 2004
||Posted: 22 May 2019,10:18
It's always best to 'trap' a SW drain, whether it's a gully or a linear channel. At the very least, it helps control "odours" that can affect any SW system.
Whether you connect the linear channel via a gully, a sump unit or a P-trap doesn't really matter, but I would most definitely "trap" the connection somehow.
Downspouts plumbed directly into the linear channel by cutting a hole in the grating are fine, if you like that look, but if you do choose that option, make sure there's a leaf-guard fitted at the channel outlet, as leaves from the roof will be washed directly into the channel and they have a nasty habit of obstructing outlets. Downspouts with a standard shoe-fitting discharging onto a channel with grating rely on the grating to act as the "leaf-guard" so blocked outlets tend to be less of a problem.
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