Installing downstairs loo under stairs

[Bubbles121]

Hi - hoping for some advice. We need to install a downstairs loo in our house but we're not sure where we would install it - under the stairs seems the most logical but the soil pipe is inside a wall void in the kitchen against a different external wall. I don't want a macerater - had one in a flat years ago and it was awful. Is it possible? Would they rip up the floor? Does anyone have any experience of this? I would prefer not to spend more than about £5k all in

Hi I haven't yet had it done but where having a basic under stairs toilet and basin fitted in what is currently a storage cupboard - our soil pipe is inside like yours but when we got the floors up it was quite accessible. Our builder has quoted £1000 for the job but that's alongside fitting a new kitchen.

Thanks :) sadly we have concrete floors downstairs so I assume that won't be an option (although happy to replace the kitchen floor!)
Argh - it's so much harder than I expected to just add a toilet!