To all the plumbers,
Added a pergola to house a couple of years ago approx 10 meters in lengh of the roof area and around 25 sq meters feeds back into existing gutter other side of pergola 12 meters in lengh 30 sq feeds into 12 meters of gutter which i plumbed back into 2 existing 90mm downpipes.
During very heavy rain my gutters along pergola/house overflow i was going to add an additional downpipe in middle of this section but often wondered there is only a single 90mm storm water along side of house which currently collects from 3 90mm downpipes and 24 meters of gutter inc my pergola and feeds to 100mm pipes where it joins from other side of house before entering LPOD is this single 90mm pipe able to handle all the water from the 24 mtr gutter ? i have looked at other house being built in area and see this is the norm will i get any benefit from additional downpipe or is the buried storm water pipe quite capable of clearing all this water.
Reagrds Dean
http://i723.photobucket.com/albums/ww23 ... G_1755.jpg
All gutter sections in photo are approx 5.5 meters long and feed back into 2 existng 90mm down pipes