Ceiling gap height for lighting

[Pocster]

I thought the gap between ceiling and structure had to be at least 30cm .

Understand this requirement for timber joists etc . But if it’s a concrete ceiling ; what is the min ? 
 

ta ! 

[MikeSharp01]

There isn't one as far as I know, Our Building Control scrutinised drawings show a 50mm gap between the inner face of the plaster board and the inner surface of the rafters / joists and that is all the service void we have. If you have to have 30cm (300mm) everywhere rooms would be so much smaller.

[Pocster]

5 minutes ago, MikeSharp01 said:

There isn't one as far as I know, Our Building Control scrutinised drawings show a 50mm gap between the inner face of the plaster board and the inner surface of the rafters / joists and that is all the service void we have. If you have to have 30cm (300mm) everywhere rooms would be so much smaller.

that would explain why I couldn’t find one ! . Right ! - tighty it is ! 👍

Edited February 16, 2023 by pocster