Alternative route to plumb a toilet? Possible?

[dishman]

I have a downstairs toilet that has a Saniflow.

When it was installed it was impossible to meet up with the external main downpipe because:

1) there is and external attached garage and utility on the other side of the external wall.
2)There was also a doorway in-between the downstairs toilet and the main downpipe (but the garage makes this a moot point anyway.

So, other than diggign up the floor of the garage and routing it to the drain, the saniflow was the cheaper option.

To meet the main downpipe the saniflow goes through the external wall into the garage, up to the garage roof height, cross over the utility room roof and over the door (that was in the way), and then connects to main drain downpipe.

However, after crawling into the subfloor beneath the toilet, there is a good bit of height down there. Whilst down there I crawled along past/beneath the doorway and low and behold I can see through some brickwork, the main downpipe! This is just below dpc level and exterior ground level obviously.

What is the possibility of routing a waste pipe down through the floor and meeting up with this main down pipe? Then being able to securely attach it to the main downpipe with only limited access to one side of it through an exterior cavity wall?

Too ambitious?

I do despise the saniflow....

 

[PrenticeBoyofDerry]

You need at 450mm from the toilet connection to the drain invert bend at the bottom of the soil stack. If you do not have this, you cannot directly connect to the stack. You will have to make allowances for the fall from the toilet to the stack, which is a minimum of 19mm per metre.

 

[Ian H]

I think if you can fit a junction through the wall then it's possible.

What's the downpipe made of?

 

[Nige F]

only limited access to one side of it through an exterior cavity wall?

Too ambitious?

I do despise the saniflow....

you need to get all round the pipe outside

 

[dishman]

I think if you can fit a junction through the wall then it's possible.

What's the downpipe made of?

hmm, not sure how easy it will be to fit a whole junction.....it is also made of cast iron........

Is there an option to fit an appropriate size junction strap/boss? Or do they not go up to that size?

 

[Ian H]

No, they don't come that big.

You could cut a section out and put a T piece in but it sounds like it might be a bit dodgy with cast iron. You often find the brackets holding cast iron are corroded and the stack is holding itself up.

How deep would you have to dig outside to expose it fully?

 

[dishman]

It is all boxed in, in the utility room. I am a bit loathed to open it all up on a whim.

Oh well, it was just a thought. It only crossed my mind due to it being visible from the sub floor. There is easily enough fall from the toilet, although I am unsure about how much distance to the drain invert bend @PrenticeBoyofDerry mentions. As I said, the location is roughly level with the DPC.