Roughing out Bathroom plumbing

[CoxHQ]

Hello, I'm renovating our bathroom and as it's the first time I've done this I thought I'd ask you guys if I'm on the right lines. I've uploaded some images.

We're having an extension built and the new roof covers where the old waste exits into a rainwater hopper. The rainwater will be diverted, and I intend to move the bathroom waste over, and connect it to the soil pipe with a strap boss. We also intend to replace a downstairs window with a back door.

My concern is that there won't be much room around the waste exit and the Soil pipe and the back door. Can I connect bath and basin waste internally if I use 50mm pipe and anti siphon traps thus giving me only one pipe to connect to the stack?

Also, does it matter which route my hot and cold feeds take. I'll be using push-fit.

Any extra advice appreciated,

Cheers

 

[Crofton Gas]

Take the easiest pipe route, whichever that is, making sure you have access to the fittings. The bath and sink can be combined internally, you don't necessarily need to go up to 50mm, as it's unlikey the bath and basin would be drained together, swept 40mm tee with 32mm reducer from basin

 

[Hot&Cold]

going by the computer drawn images with no dimensions,an external soil manifold could be considered and the h&c pipes are usually run around the perimeter of the floor. There are guidance rules for butchering joists and an approved document for new soil/drain work.
​

On site considerations could be very different and everything above is just a guide,why not get it all professionally installed

 

[CoxHQ]

Thank you both for your help. So I'll have all of my h&c connections just inside of the bath panel for access and run individual pipes to the toilet basin and mixer.

I'll have a look into an external soil manifold but if it's ok to go with one waste pipe that would be great.

There isn't much space between the basin and toilet (the computer images are to scale) - would it be ok to have the basin and bath waste meet in the middle (equal T) and then exit as one or would it be better to try and fit the short steep drop to the soil pipe between the basin and toilet?

I've attached a photo of the current exterior to give an idea of size.

I would love to get someone in to do the whole bathroom but some unexpected complications with the extension have used up all of our contingency. Thanks again for your help!