Whats the easiest way to install an extractor fan in a bathroom when you cannot get into the ceiling vod as above the bathroom is a dormer?

L+T idea is right but their 75-100 mm hole is excessive, I normaly make a small hole in the wall plaster where it meets the ceiling and possibly in the ceiling, allthough it is not easy to feed the cable through I have not failed yet,this leaves only a small hole to fill and if you use trunking for the cable this covers most if not all of the hole but take note of pcm"s comments,regards Terry.

Install the fan into an external wall.

Depending on the direction of the rafters, you can feed a fibre glass rod through the light opening in the ceiling to the required position above the fan. If you drill a 75mm to 100mm hole in the ceiling above where the fan is being fitted then you can usually grab the rod with your hand, attach the cable and pull it back to the light fitting. Placing some timber above the hole you drilled will allow you to put back the piece you drilled out which will then require a small amount of filler or plaster.

install it in an external wall. don't forget to install an fan isolator switch.

Hi my name is Ian the only other way is thro the wall Sorry

through a wall

Just to add,anything installed in a bathroom including extending existing circuits needs to be protected by a 30mA rcd,it also comes under Part P and is notifiable .