Extractor fan in new downstairs WC?

[MsShopper]

As part of an extension and refurb next year, we're putting in a new downstairs toilet in what is currently a good-sized cupboard under the stairs.

However, reading up on building regulations, I'm wondering how we will meet the requirements for "extract ventilation to the outside", as the stairs is on an internal wall. The nearest external wall (to run ducting to) would be at least 3 metres away. Has anyone encountered this problem before? Any words of advice/experience would be appreciated!

In my house the cloakroom toilet (under the stairs) is a long way away from an external wall.

The fan ducting runs through the floor/ceiling (between the ceiling of the toilet and the floor of the second floor) and out the back of the house.

Question is how difficult this is to put in place retrospectively.

I suppose you could put a service duct along the room next to the toilet.

Otherwise you would probably have to take the ceiling down, install the ducting and then replaster.

Thanks for that! I hadn’t thought of going up - that might work. The main bathroom is the other side of the wall to the new WC, albeit one floor up.

I didn't think, but it may depend on the direction of your joists.

I don't know much about upper floor construction, but I guess it is just a series of beams running across (joists), with plasterboard stapled to the ceiling side, and flooring boards stapled to the upstairs side with gaps in between.

If the joists run in the right direction you can thread ducting through the gap probably no issues. However if the joists are running perpendicular to the direction you want to go in it is more tricky maybe as you would have to slice through the joists. If that makes any sense ?

If the main bathroom is one floor up, it might be better to take the ducting into that, and out that way. Once you get to an upstairs floor it is a bit easier, because you can just take the duct into the loft and then run it to the outside over the rafters, or maybe you could run it behind the bath and to an outer wall depending on your bathroom format.

Anyway, good luck !

Oh yes, good point about joists. I’ll persuade my DH to have a look under the floorboards this weekend. Thanks for your help!