Somersoft Property Investment Forums  

Go Back   Somersoft Property Investment Forums > Property Investment Discussions > Adding Value

Reply
 
Thread Tools Display Modes
  #1  
Old 19-02-2011, 09:53 AM
brendio brendio is offline
Member
 
Join Date: Jan 2010
Location: Wide Bay, Qld
Posts: 396
brendio will become famous soon enoughbrendio will become famous soon enough
How much roof area can you drain through one 90 mm stormwater pipe?

I was just wondering if there is a maximum area of roof that you can discharge through a single stormwater pipe out of the curb. Our plumber, instead of piping the downpipe on the front corner of our house out to the curb 10 m or so away, has instead piped the stormwater (uphill slightly) all the way around the house to the opposite rear corner (about 35 m) to join up with the rest of the downpipes and has the entire house draining through a single 90 mm pipe to the curb on our side boundary (corner block). The area of the house would be just under 300 sqm. Just under half of that goes into a tank, but if we get a lot of rain (like recently) and the tank is overflowing into the stormwater pipe, that seems like a lot of water to be going through a little pipe and I am worried the gutters will overflow. The house was previous serviced by three stormwater outlets before we moved it.

Any plumbers out there know if there is a rule of thumb for how much area a single stormwater pipe can handle?
Reply With Quote
  #2  
Old 19-02-2011, 02:11 PM
Pa1nter's Avatar
Pa1nter Pa1nter is offline
Member
 
Join Date: Nov 2009
Location: Brisbane Qld
Posts: 1,532
Pa1nter is a splendid one to beholdPa1nter is a splendid one to beholdPa1nter is a splendid one to beholdPa1nter is a splendid one to beholdPa1nter is a splendid one to beholdPa1nter is a splendid one to behold
Quote:
Originally Posted by brendio View Post
I was just wondering if there is a maximum area of roof that you can discharge through a single stormwater pipe out of the curb. Our plumber, instead of piping the downpipe on the front corner of our house out to the curb 10 m or so away, has instead piped the stormwater (uphill slightly) all the way around the house to the opposite rear corner (about 35 m) to join up with the rest of the downpipes and has the entire house draining through a single 90 mm pipe to the curb on our side boundary (corner block). The area of the house would be just under 300 sqm. Just under half of that goes into a tank, but if we get a lot of rain (like recently) and the tank is overflowing into the stormwater pipe, that seems like a lot of water to be going through a little pipe and I am worried the gutters will overflow. The house was previous serviced by three stormwater outlets before we moved it.

Any plumbers out there know if there is a rule of thumb for how much area a single stormwater pipe can handle?
I have around 330m2 of roof on my PPOR ,I have 2 x 100mm stormwater and when we get decent rain it cant keep up.

Only one thing can happen is your gutters will back up and water can flow over the back of the gutters into the eves and into the walls of your house

I had a similar problem with a lazy plumber,and after he finished ,I fitted rainhoods,so excess water flows over them instead of the gutters.
You can see in the photo,simple but effective.
Attached Thumbnails
Click image for larger version

Name:	exterior finished.jpg
Views:	479
Size:	97.1 KB
ID:	7171  
__________________
There is a Bargain of a lifetime
EVERY DAY
Reply With Quote
  #3  
Old 19-02-2011, 03:24 PM
tiger97 tiger97 is offline
Member
 
Join Date: Sep 2010
Location: Melbourne
Posts: 38
tiger97 is on a distinguished road
I think the code is generally a downpipe no greater than every 12meters.

Hope this helps.

Scott.
Reply With Quote
  #4  
Old 19-02-2011, 06:32 PM
RumpledElf's Avatar
RumpledElf RumpledElf is offline
all fun in the big city!
 
Join Date: Apr 2008
Location: Sydney
Posts: 5,633
RumpledElf is a splendid one to beholdRumpledElf is a splendid one to beholdRumpledElf is a splendid one to beholdRumpledElf is a splendid one to beholdRumpledElf is a splendid one to beholdRumpledElf is a splendid one to beholdRumpledElf is a splendid one to behold
The stormwater plan the builder has given us has a good half dozen downpipes ... that all join together into one at the back, so effectively 150sqm going into one 90mm pipe. Probably need a decent rainhead for the back, but its not on the plan, and this is allegedly drawn up by an engineer. The rainwater tank itself only has one 90mm inlet and outlet.

If there's standards, not sure what they are ...
__________________
Low income property investing - because we're not all rich.
Need a website made? We can do that!
Reply With Quote
  #5  
Old 19-02-2011, 07:23 PM
Rockstar's Avatar
Rockstar Rockstar is offline
Member
 
Join Date: Mar 2008
Location: NE Coastal NSW
Posts: 2,282
Rockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud ofRockstar has much to be proud of
I am currently building a 2 bed home which has been engineered for stormwater detention. Prior to the water reaching the detention tank there are 5 x 90mm downpipes which join into 2 x 100mm pipes as soon as they reach the ground - and then feed into the tank. The roof area is approx 100sqm and the gutter size is 150mm quad. The system is designed to handle most storm events (except 1 in 20yr event)
Reply With Quote
  #6  
Old 20-02-2011, 01:55 PM
brendio brendio is offline
Member
 
Join Date: Jan 2010
Location: Wide Bay, Qld
Posts: 396
brendio will become famous soon enoughbrendio will become famous soon enough
Thanks for the responses guys. I might have to look into those rain heads.

I did a bit of googling and came up with this site with calculators for required downpipes and storm water outlets. Having a play with it (if I've put in the right numbers), it seems to indicate that one 90 mm stormwater outlet is enough (though it would be gushing 19 L/sec in a 1 in 20 year storm), but we need a lot more downpipes, like about 14. There are currently only about 3 or 4 on the main roof, and a couple more on window awnings.

That said, a condition of our subdivision is that we are to provide two points of connection in the kerb for roofwater discharge (galvanised steel adapters). So there is obviously allowance there for more than one outlet. Don't know why our plumber thinks we only need one for such a big house and big block.
Reply With Quote
  #7  
Old 21-02-2011, 03:29 PM
Gools's Avatar
Gools Gools is offline
Member
 
Join Date: Jan 2008
Location: Adelaide, SA
Posts: 812
Gools has a spectacular aura aboutGools has a spectacular aura about
Brendio, what about the ground storm water too. Does that go into some grates and use the same pipe to the street as the down pipes?
Reply With Quote
  #8  
Old 21-02-2011, 08:26 PM
brendio brendio is offline
Member
 
Join Date: Jan 2010
Location: Wide Bay, Qld
Posts: 396
brendio will become famous soon enoughbrendio will become famous soon enough
No, not at the moment. It has a couple of acres to soak into. Once we subdivide though, there will be interallotment drainage for the ground stormwater to drain into so it doesn't cross neighbouring boundaries.
Reply With Quote
Reply

Tags
plumbing, stormwater

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time now is 10:57 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright © Somersoft Financial Services Pty Ltd