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Posted: Thu Feb 17, 2011 10:41 pm
by joydivision
A seperate toilet has been moved from the rear of a property and put in the bathroom which initially only housed a basin and bath. The bathroom is on the front of the property.
The bathroom wastes end up in a trap gully along with a rainwater pipe at present, and a soilstack has been created next to this gully and joins the gullys underground drainage on a y junction as its a duel syatem.
Problem is, the original underground drainage has almost no fall from the gully/soilstack for the first 3 meters or so and due to this, backflow is occuring from the toilet and ending up with toilet paper etc in the gully trap!! not good!!
What solutions are there?
The gully/soilstack cant be raised any more to create more fall, and chasing the line of underground drainage back to get a substantial fall is really a very last resort as i will end up chasing it quite a way!
Im thinking of conecting the soilstack to the underground drainage further away from the gully, so in theory i will have to seperate runs for 1.5 meters or so until they y junction together.??
Other idea is a non return valve on the stack and gully, but to be honest, i have never used these and know little of them, plus they seem pretty pricey!!
Cheers for any advice
allan
Posted: Thu Feb 17, 2011 10:48 pm
by lutonlagerlout
saniflow is your friend here
if there really is no fall (which can happen) then a macerator can get you out of trouble
other than that ,hook the lot out and redo in plastic
:O £££££ :O
cheers LLL
Posted: Thu Feb 17, 2011 11:16 pm
by joydivision
yeah, not cheap either way!
thanks for the advice.
Any ideas if the valves would work on a situation like this?
Like you say, the first couple of meters of original drainage is pretty much level, maybe a couple of mm in my favour!
cheers again
Allan
Posted: Thu Feb 17, 2011 11:56 pm
by lutonlagerlout
well plastic you can get away with 1:80 fall
old clay pipes tended to have around 1:40
never heard of any non return valves in a foul pipe
LLL
Posted: Fri Feb 18, 2011 1:16 pm
by seanandruby
can't you run the foul directly to manhole, or put in a new manhole further down the line rather than an oblique branch junction?
Posted: Fri Feb 18, 2011 2:52 pm
by Pablo
Most of the darinage manufacturers make a shallow gully that would allow you to replace and raise the fall of the existing one. I think the non return valves are for flood water only and wouldn't work if there was no fall and even pressure on both sides.
Posted: Fri Feb 18, 2011 6:19 pm
by flowjoe
Are you sure a 45 degree junction was used and not a curved square one, you shouldn't get any surcharge even if the pipe is level with the force behind it being so close to the SVP.
Moving the connection further away will help, renewing as much of the old run as possible in plastic will also help because as LLL touched on modern pipes are a lot smoother
The are non-return valves for foul waste but all that will happen is the paper etc will build up, move down the line and cover the end of the junction from the SVP.
Posted: Fri Feb 18, 2011 10:27 pm
by joydivision
Thanks everyone for the advice.
On further insepction today and revealing more of the line of underground drainage, it seems when i got the level on it there is actualy a backfall of around 40mm from the point the new drainage was connected for around 2 meters, then begins to fall the correct way.
So looks like il be pulling the existing up quite a way and renewing in plastic tomorrow!
Cheers again
Allan
Posted: Sat Feb 19, 2011 4:36 pm
by seanandruby
You really need to be thinking of installing an inspection chamber. Foul drainage needs to be accessible for maintenance.
Posted: Sat Feb 19, 2011 7:42 pm
by haggistini
backfall is better than no fall at all
:;):
Posted: Sun Feb 20, 2011 7:51 am
by seanandruby
haggistini wrote:backfall is better than no fall at all
:;):
That is not true hag. I know your saying it as a joke but you would'nt believe the amount of drainlayers who quote that phrase and go with it. It should be thrown in the skip along with " that's near enough, that's good enough, can't see it from my house". "That's perfect, spot on, bang on," are much better :;): If it's near enough it's good enough, so it must be good enough, because it's near enough :laugh:
Posted: Sun Feb 20, 2011 7:53 am
by Mikey_C
or my personal favourite from a mate who was ex navy "close enough for government work"
Posted: Sun Feb 20, 2011 8:15 am
by Dave_L
"Near enough for a job in the country!"
Posted: Sun Feb 20, 2011 12:19 pm
by lutonlagerlout
alright for a country job :;):
spot in-ish :O
it wont be seen 
LLL
Posted: Sun Feb 20, 2011 1:55 pm
by flowjoe
Isn't it the street mason who says to the scientist its OK for you guys working to a micro-millimeter, but these flags have to be spot on !:)
Edited By flowjoe on 1298210179