Hi,
I moved into a house with a side extension garage which has a flat roof on top of about 6 feet of tiles set at 45 degrees. The original flue outlet from the side of the house has been cut just below the flat roof and diverted through a vent in the tiles. The roof space is a bit cluttered with the pipe and I thought I would fit a vent valve and remove the pipe across the underside of my roof. I was told some time ago that I could only do this if there was a "free vent" elsewhere on the property. Could someone confirm this is so and if so why is it necessary?
Thanks