Connecting Drainage Hoppers

[malcolm]

I want to lower a drainage hopper by around 275mm to put it below internal floor level and add an inspection chamber like this one http://www.pavingexpert.com/drain15.htm where it joins the foul drain.

The drain pipe and cast bathroom waste pipes are about 250mm apart so I'm looking at two hoppers side by side. Ideally I would have the bath waste one drain into the main one and have a single P trapped pipe to the inspection chamber.

How does this tend to be done?

 

[123hotchef]

check with building regs because I know from experience where I live the rain water has to be diverted to a soak away yeh I know more work!

 

[I'm getting on a bit]

Low back p trap and integral hopper search on toolstation

Existing no need for building regs, new extension = soakaway

 

[malcolm]

The pipes are too far apart for a single hopper. It would be much easier to have two of them side by side, just I'm not sure how they would be connected together.

 

[BrokenBiker]

as above, as you are modding an existing system no need for building regs to clear it

 

[I'm getting on a bit]

The pipes are too far apart for a single hopper. It would be much easier to have two of them side by side, just I'm not sure how they would be connected together.

I don't have the hole picture of what you are trying to do

But one soil pipe up the building toilet pan goes to this. This then goes directly to inspection chamber

Sink/bath wastes go to stack via strap on bosses

Rainwater goes to gully, gully goes to inspection chamber

 

[malcolm]

The hopper that is there at the moment is much wider than the plastic hoppers you get nowadays. There are 4 pipes going in - 2 drain pipes, bath waste and kitchen waste. I could probably rearrange the pipes but they would be a tight fit in a single hopper and maintenance would be restricted.

I'm thinking about having 2 hoppers almost side by side. I guess the only way to do this is to have two lots of pipe going to the inspection chamber and there is no way to link the two hoppers together and use one pipe to the inspection chamber?

 

[Kayos]

You can link them with a swept tee if you have the height

 

[malcolm]

Not really the height unless I connect after the P traps which would make rodding less easy. I think I might just fit two hoppers and run two separate pipes to the inspection chamber - if I try to stuff everything into one hopper I won't have access to clear it out.

Only real snag with that is it will use up all the connections on that side of the inspection chamber and I was hoping to save a connection to one day connect the soil pipe which currently has it's own manhole inside the house (I don't think building regs were involved in that extension ). Maybe I could connect that to the other side using easybends.

 

[mike os]

I would be tempted to redo the pipework and put a stack in to connect that lot into.

if there is no toilet there you could use a stub stack but if you can putting a vented stack in is never a bad idea

 

[malcolm]

I'm tempted by a vented stack. It's an old building and I had been keen to retain at least the cast iron hopper to the upstairs bathroom, but I'm up against ground levels.

The trench to the right of the photo below is 100mm below kitchen floor levels and I only have 200mm height from top of hopper to the invert in the inspection chamber entry which reduces options.

How easy would a vented stack be to modify in future? I guess they are glued. I'll be moving the kitchen sink and one of the roof drains within the next year, though I suppose I have an idea where they will be so could incorporate blanked entries into the stack. There is a window up there so the stack would presumably need to bend up above roof level but I don't think I have much chance of an air tight seal to the aluminium guttering. More research needed and any tips appreciated.

 

[Kayos]

Most soil is push fit, lube the joints and they will come apart if needed with minimal fuss

 

[malcolm]

That could be an idea then. I had forgotten I half planned to put a toilet into the upstairs bathroom if I can figure out where the airing cupboard might go so a soil stack running up in about the right place might well be an advantage.

 

[mike os]

Very easy to adapt, use pushfit and a silicone grease on the bits you may want to remove. smaller pipes can be attached to the stack using a glue on boss at a later date

 

[tinman123]

Not really the height unless I connect after the P traps which would make rodding less easy. I think I might just fit two hoppers and run two separate pipes to the inspection chamber - if I try to stuff everything into one hopper I won't have access to clear it out.

Only real snag with that is it will use up all the connections on that side of the inspection chamber and I was hoping to save a connection to one day connect the soil pipe which currently has it's own manhole inside the house (I don't think building regs were involved in that extension ). Maybe I could connect that to the other side using easybends.

i think im with you, but im not fully either.

that looks like a 450mm base which is a good size, i see you have two fittings to the side you need to be but because of height restrictions you cant make use of the other side i take it.

are you going to dig out the rest of the concrete there and lower the street level or are you concreting it back to the height i see in the pic now.
so the bit your wondering is how to pipe the 4 pipes into the 2 fittings on the 450 base i take it, this bit im not sure on so ill ask, is the whole ground being lowered down and are you planning on extending the 4 pipes down to a lower gully trap or are you looking to get rid of the concrete trap thats there and just wanting to put in proper gully traps at the same height?

 

[malcolm]

I have a wet wall in the kitchen behind the current drain so my plan is to drop the level of the drain down to the bottom of the trench which is below kitchen floor level. The trench will be covered by grating. Allowing for a 1 in 40 run to the foul drain the invert of the gully would be only 165mm below the bottom of the trench. I'll have to raise the gully up a bit above trench level.

I'm trying to figure out how to use only one of the inspection chamber connections so I can use the other for a WC later on.

A single vented stack will be tricky as there are rainwater downpipes which would need traps. Also the vented stack is a bit ugly.

Popped into buildbase this morning with a tape measure and I could use a Hunter gully which is shorter than a Flowplast gully. I can probably fit all of the pipes into a single gully if I make them removable for access - it doesn't need to be neat if it is covered by grating. Anything else starts getting a bit messy and there isn't the height for a direct connection from another hopper to the gully unless it includes a P trap.

 

[mike os]

if the stack is vented then you dont need to trap the rwdp's (assuming they are all external)

if you know where the WC is to go just put a t in and cap it

 

[malcolm]

I don't think you can connect rainwater to a vented stack as the gutter will act as a vent and is in the wrong place for building regs. I'll probably not bother adding another WC so don't really need a stack. Can always put a soakaway in later on for the rainwater if I change my mind.

 

[mike os]

is anyone checking?

 

[malcolm]

It's one of the things building regs want to look at.

The one thing I can't find is if there is a minimum height for gullys. There will be a flow to the inspection chamber but the bottle would be lower than the inspection chamber invert level.