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The ventilation shaft in my flat runs straight across from kitchen/bathroom vents through the living room to the outlet on an exterior wall. (This shaft exclusively serves my apartment.) The problem is that the ceiling level in my living room is aligned with the ventilation shaft and so is drastically lowered. To take full advantage of the room height can I re-route the ventilation shaft up to the actual ceiling height and down again on other side to the existing wall outlet? Are the regulations for this?

Hi markusb,
Provided the duct remains below a continuous plasterboard ceiling yes you can go up and down. Do not do anything to pierce what may be a fire-resistant break between you and whatever is above your apartment. Bear in mind it was not installed as you propose for a reason, which may not be apparent until you try yourself.
Regards S

Thanks S,
That’s really helpful. We would definitely be staying within boundaries of our flat, which is easy as there are concrete ceilings between us and our neighbour above. Two follow-on questions:
1) Ideally we would re-route the metal ventilation duct so that it tightly tracks the contours of the living room with our newly heightened ceiling. That would mean a 90 angle as the duct exits from the bathroom and another 90 degree angle to track across the living room ceiling. And then same again down the other side of room to use the existing vent on the exterior wall. Would those sharp 90 angles also be ok?
2) The lowered false ceiling is made of plasterboard and there’s only a small layer of generic yellow insulation material scattered over it. That does not look to me like a “fire-resistant break”, but what do you think?

Hi markusb,
The concrete is an effective firebreak in itself as long as there are no piercings through it.
Bends should not create an issue provided there is forced ventilation.
Regards S