I built what I thought was a relatively simple, 3 bedroom, single storey home with a volume builder in 2010. I moved in December of that year after copious delays, damage to the home caused by useless tradies and general argument/stress. The 3 month maintenance then took up most of 2011 including a shower having to be removed and replaced 3 times and repairs to the plaster where the roof had leaked.
Anyway ever since I moved in there has been an unpleasant smell in the bathrooms. In the initial maintenance period they discovered that the "stink pipe" (vent that goes out through the roof) had been cut off and tiled over by the roofers
So I called the builder and (credit to them here) they sent out a "maintenance team" member who then contacted their plumber (whom it should be noted was a different plumber to the one who did the house in the first place; that company having gone into recievership!). The new plumber came out this past weekend and had a bit of a look around. He established that the toilet had not been connected properly so the smell from the sewer was leaching back up into my house
The good news is that it can all be fairly easily rectified but it has certainly taught me to follow my gut and seek more information even when others have told me to just let it go.
Cheers