Reducing Toilet Waste Pipe Diameter

[davideljones]

Hello,

This is my first post, so please be kind!

I am looking at reducing the diameter of my toilet waste pipe. At present it runs along the side of the bathroom and looks terrible, so I would like to relocate it into the cavity within the pasterboard wall to run into the waste stack, effectively hiding the waste pipe. I'm not sure how much I want to reduce the diameter by, but I would say around 10mm.

Am I able to reduce the size of my wastepipe, or is this against building regs, or will it just not work from a technical point of view?

Many thanks,

David

 

[Steady]

Assuming your current soil pipe is 4" (110mm) plastic you could reduce this to 82mm as pipe and fittings are available in this size.