Can I route an extractor fan's ducting to this solum vent?

[spicytea123]

Hey everyone,

I'm in the process of planning out the renovation of my bathroom and have been trying to decide the best method of creating a flue for an extractor fan.

My first thought was to either core drill or stitch drill a 4 inch hole through the exterior wall next to the window however this is a ground floor tenement flat and therefore the walls are likely to be made of 3 feet sandstone. So not a simple task in the slightest.

My latest idea was to replace the solum vent under the floorboards (as circled in the photo below) with a flap vent and connect the ducting on the outlet of the extractor fan to this.

This would require the ducting to travel approximately 2 meters vertically down from the extractor fan, a meter along the solum and out the vent on the right.

Is this is a viable solution? How necessary is the solum vent? Is there such a thing as a split solum/flap vent so that it can provide a vent for both the solum and the extractor fan?

 

[DAZB]

I can see problems doing that as the warm steam would cool on the long trip out and condensate on the inside of the ducting and you would have an issue with moisture inside the duct. A sandstone wall would not be too difficult to drill through and with a core drill and extension bars you could be through it faster than you think or, as you mention, stitch drill it with a long SDS bit.

 

[spicytea123]

I can see problems doing that as the warm steam would cool on the long trip out and condensate on the inside of the ducting and you would have an issue with moisture inside the duct. A sandstone wall would not be too difficult to drill through and with a core drill and extension bars you could be through it faster than you think or, as you mention, stitch drill it with a long SDS bit

Thanks for the advice. Do you think I could reduce the moisture issue if I used insulated ducting? As much as I agree drilling through the sandstone wall wouldn't be too bad it's more the location of the wall and the accessibility of it. Drilling from the inside is not an option as there is another interior wall blocking it from the inside and drilling from the outside is not an option unless I can be absolute certain I'm drilling in the correct place, which isn't possible due to the aforementioned.

 

[DAZB]

Using an insulated ducting would help but it is not possible to know how it would perform until you try it. Can you set up a practice run and see how it performs maybe ?