my mothers neighbour has a cooker hood extracting into the roof space which is also the same space as my mums kitchen roof space as there is no dividing wall in the roof. The problem is the extracting pipe does not vent to the outside, just into the roof space. As you can probably imagine the smells are coming through into my mums kitchen. IS THIS LEGAL? It seems like a health risk to me. My mum has told the neighbour but he seems to have no urgency to do anything about it. In fact I think he thinks there is not problem with it how it is, even though my mum has to put up with the smell of rotten fat that is building up in the roof space. DOES ANY BODY KNOW THE REGULATIONS IN THIS MATTER