Help please? I would like to build an extension or conservatory behind our garage. I think this should be reasonably inexpensive as there are already two walls that can be used... BUT the boiler is on the inside of the garage wall and if we had any thing built on the other side of the wall we would need to move the flue. The flue is only about 8 feet off the ground and apparently we can't just put in a chimney as the outlet would then be near the bedroom window - does anyone know if there are rules about this? Also does anyone have any ideas about how much it would cost to re-site the boiler on different wall and whether would we need to replace the only-just-adequate-for-the-size-of-house combi boiler (circa 10 years old) with a more modern high effeciency model, or would it just be sensible to do this anyway?