New extension u/g drainage

[Fastjedi]

I am about to begin a single story extension (Bedroom / Bathroom / Utility). Beginning at the new bathroom the 110mm PVCu drain will consist of a rest bend into a 5m straight run to a 450mm IC. I have two questions

1. The drain will run directly under the utility room. I would like to drop a 110mm drain into the 5m run from above for the washing machine (at about half distance between the bathroom and IC) but am not sure if this is allowed / what components to use. I am guessing it would need to be 'rodable' from both the bathroom and the utility?

2. In the bathroom the U/G drainage will land behind a false studding wall to create a pipe cavity (150mm wide). I would like to either miss out the concrete floor above the insulation or find some other way of dropping start of the soil system by 100mm or so in order to allow more scope. I have a lot of connections to make! (2xWC's, 2xbasins, 1xShower 1xbath). Any advice of this apprieciated)

[Tony McC]

Your architect should have designed the drainage for you!

1 - might it be possible to provide rod access from the washing machine end of the spur?

2 - without a layout plan (or seeing the site) I can't really make any comment.

[Fastjedi]

The end of the run (in the bathroom) will have a rest bend into the soil stack ... and will therefore be rodable past the washing maching junction through to the next I/C

Logic would tell me the washing machine branch should consist of a 45 deg equal branch in the main drain run pointing upwards > about a metre of 110 PVCu pipe > 45 deg bend > 110 PVCu pipe to floor level in the utility. Cap it with one of those bung things and run the w/m waste pipe into that. This should mean the drain is rodable from the utility too.
Alturnatively, I guess the 45 deg bend could go at the top of the pipe just below floor level ..... or perhaps there is some trick of the trade where I could run the w/m into a 45 deg access point!

I was rather hoping the architect would provide a little more detail in the plans (It shows only centre lines and I/C's) ... especially as he knew it was likely to be a 'self build'

Would welcome your thoughts (even though I appreciate it is an impossible question w/o the plans)

Best Regards,
Ian

[Tony McC]

That sounds OK to me - as long as you can access each and every part of the system, the BCO shouldn't give you any grief.

[Fastjedi]

An additional question relating to the same drainage run.

At the distant end the drain will serve 1x bath, 2x basins, 1x shower. I plan to use an air admittance valve on this stack.

At the utility I was planning the bring the under ground drainage to floor level. The washine machine waste will go via a stand pipe u bend into a waste adaptor in the top of the drain.

Someone suggested I would have to fit a bottle gully the other day ... but this seems a bit weard within the building. I would much rather do as above if it is accepable as it is much neater in my opinion

Regards Ian

[Tony McC]

I can't understand why a bottle gully would be needed, especially with a foul line. Bottle gullies are for surface water.