ducting

Hello, you could take the ducting up through the ceiling into the void where the timber joists are, exit the ducting through the external wall, you would then need to bridel the floor joists to strengthen where you have cut out for the ducting to go through. If you need any more help with this get untouched and I can advise further.

If you want to retain the full 2.5m ceiling height in the bathroom, the best solution would usually be to run the duct within the ceiling void, between the joists, provided there is sufficient space available. If that is not possible, another option may be to route the duct through the flat roof area and then out through the external wall. The duct should be insulated and installed with a slight fall where appropriate to help prevent condensation issues. The most suitable solution would depend on the existing structure and available space, so a site inspection would be needed to confirm the best approach.

For a WC extractor duct passing through a bathroom where you want to keep the full 2.5m ceiling height, I would consider the following options in order of preference: Option 1 – Run the duct within the floor/ceiling zone (best solution) If the bathroom is in a side extension with timber joists above, route a rigid 100mm or 125mm duct through the joist zone and out through the external wall. Advantages: * No boxing-in or bulkhead required. * Bathroom ceiling remains at 2.5m. * Cleanest finish. Points to check: * Joist depth available. * Direction of joists. * Whether holes can be drilled through the neutral zone of the joists in accordance with Building Regulations. Since you mentioned there is no steel beam, this may be achievable if the joists run in the correct direction. ⸻ Option 2 – Use a flat duct system Instead of round ducting, use a low-profile rectangular duct such as: * 220mm x 90mm flat duct * 204mm x 60mm flat duct These can often be concealed within: * Stud walls * Service voids * Boxing behind sanitaryware * Floor zones A flat duct can provide similar airflow while requiring much less depth. ⸻ Option 3 – Box within a wall rather than the ceiling If the WC backs onto a stud wall in the bathroom, create a service zone inside the wall and run the duct vertically or horizontally within the partition. This is usually far less noticeable than a ceiling bulkhead. ⸻ Option 4 – External route Sometimes the simplest solution is: 1. Extract from the WC. 2. Duct directly through the structural wall into the side passage. 3. Run externally in insulated ducting. 4. Exit through an outside wall. This avoids affecting the bathroom ceiling entirely. ⸻ What I would do As a builder, if the bathroom ceiling is already at 2.5m and the client wants a premium finish, I would: 1. Install a good quality centrifugal extractor fan in the WC. 2. Use rigid 100mm or 125mm ducting. 3. Route the duct through the ceiling/floor void between the WC and bathroom. 4. Exit through the nearest external wall. 5. Avoid flexible duct wherever possible. This keeps maximum airflow, reduces noise, and preserves the full bathroom ceiling height. If you can sketch a quick floor plan showing: * WC location * Bathroom location * Direction of joists (if known) * External walls

you should be able to run the ducting in the ceiling between the joists or fix the extractor on the out side wall and core bit through for extractor ducting