While looking through the building regulations I have noted that in part M detailing window manifestations that the information is a little difficult to interpret, does anyone know if it is a requirement for glazing manifestations to be at two levels? If so how would this impact on existing glazing. Any help would be greatly appreciated. M

M You mention Part M building Regs - Have you looked at Part N Section 2? - this gives details of current requirements, such as do you actually require anything on the glass. The current requirement is the middle of line of manifestation should be at 1500mm, but it does not state how thick the line should be. Something to consider is that the current Regs only apply to current construction activities, they are not retrospect. If construction took place 10 years ago then the Regs in place at the time are the ones that should have been followed. If you are concerned about any interpretation of the Regs contact your local Building control Officer, they are helpful.