Cover rising under stairs to downstairs loo

[minimimo]

Does anyone know roughly how much it costs to convert an under stairs storage space into a small downstairs loo?

Thank you!

Sorry just noticed the autocorrect errors in the title 🙈

In my experience it depends hugely on where your existing drainage is and what condition it is in...

In my case what should have cost c£2k for the downstairs loo part (I was having other work done too) ended up costing more in the region of £10k  because of problems with joining in to the existing drainage

Does it lead to an outside wall for drainage/stack pipe? Depending where the plumbing has to go is a large factor in your costs.

Be aware there's no window and it's in a 'busier' part of the house in a hall, very much less private if it's in the sitting-room. (See Mrs. Brown's Boys)

The only person I know who has had one installed under the stairs announces it's 'wees only' because there's no ventilation to remove any smells.

If it's on an outside wall you can put in a good extractor fan