2 x 135° bends in a horizontal soil pipe run

[buffster]

I'm trying to find a solution for replacing a Saniflo in an ensuite bedroom. It's a biggish, late Victorian house, and I need to get the soil pipe from the front to the back of the house. I can run the first part of the pipe in the floor as the joists run the right way, but for the second section the joists run the other way so I need to drop down and run under the joists. This section will be in an already boxed in area (the top of some built in cupboards) so won't be visable, and if I run the first section in the floor there will be no ugly boxing in in the room below, and no need to disturb the ceiling which hopefully will mean less noise transference when the loo above is used.

So, is it a big no-no to have a horizontal (well, with an appropriate fall) section, then 2 x 135° bends to lower the pipe and then another horizontal run? I know it's not ideal, but it's the best route I can find for a 4" pipe through the house.

 

[dilalio]

I'm trying to find a solution for replacing a Saniflo in an ensuite bedroom. It's a biggish, late Victorian house, and I need to get the soil pipe from the front to the back of the house. I can run the first part of the pipe in the floor as the joists run the right way, but for the second section the joists run the other way so I need to drop down and run under the joists. This section will be in an already boxed in area (the top of some built in cupboards) so won't be visable, and if I run the first section in the floor there will be no ugly boxing in in the room below, and no need to disturb the ceiling which hopefully will mean less noise transference when the loo above is used.

So, is it a big no-no to have a horizontal (well, with an appropriate fall) section, then 2 x 135° bends to lower the pipe and then another horizontal run? I know it's not ideal, but it's the best route I can find for a 4" pipe through the house.

It's fine. Go ahead. Just make sure you use solvent weld and use plenty of it on both male and female parts of each joint. You gotta do, what you gotta do!
Don't forget to put in an access elbow or T where it exits the exterior wall though.

 

[Nige F]

hopefully will mean less noise transference when the loo above is used.

.

If you're concerned about noise - google noise reducing plastic soil pipes

 

[buffster]

Thanks both.

If you're concerned about noise - google noise reducing plastic soil pipes

I must admit I was considering using some, but it's not that easy to get hold of. I looked at the Marley dBlue, and the Wavin stuff as well. Does it make a significant difference? Was going to shove some dense (60kg/m²) acoustic slab wherever I can around ordinary pipe, but would definitely be interested in the acoustic stuff if it's any good.

 

[dilalio]

Not worth the extra IMO!
Just pack some insulation in there and you'll soon become domestically deaf to it

 

[Ian H]

Use plenty of clips too.