I find myself having to install a ventilation for an internal bathroom I'm building[1]. Unfortunately there's no alternative for the exit pipe to go straight up through the roof - no direct access to any external walls as it's a mid-terrace; and because it's also a corner terrace it would be tough (and unsightly) to reach an external wall via bozed in ducting.
So how difficult is this to do, and leave a sound, non-leaking roof? What's the best device for a newbie to use? Had a look on Screwfix but can't see anything. Roof has flat tiles, think they are slate.
Thanks David
[1] Just bought the place. This internal room has apparently been used as a shower-room of sorts. There is an old ventilation grill in the ceiling, so yesterday I went up to the loft to find what was on the other side of it; hoping for at least a duct and a broken fan maybe. I found a large ancient, galvanized steel box about 18" cube, firmly fixed down over the grille. Very curious. Box had several other grilles in the sides, and one had been prised open by someone in order to look inside. The contents... nothing, zip, nada. The only purpose seems to be to provide an air conduit into the roof space. Presumably building control must have been OK with that when it was fitted!