"Philip Thompson" wrote in message
...
Trying to work out the best way to vent a bathroom using a fan with 4"
pipes
and feeding through the roof.
It is a bungalow but there is no way to vent through a wall so it has to
be
the roof.

No way? Guessing the outside wall must be all window except above the bath.
If so think about SELV fan above bath. Alternatively is it possible to duct
to the soffit?

Alan