Hi all
I am currently renovating a back room at one end of which there is a bar (as in for serving drinks). Above the bar area is a lowered "ceiling" section, basically timber frame with wood cladding. An extension was built by the previous owner above this bar with an en-suite and associated plumbing. Removing the box cladding below shows that the plumbing has been carried out in plastic pipe which hangs below joist level into the space above the boxwork.
So, to allow for a level ceiling throughout the downstairs room, can I notch the underside of the joists for 15mm plastic pipes or will this introduce serious weakness?
The joists seem quite substantial (can't remember dimensions off hand) and span about 3m. Are there rules about notching underside of joists? I've seen rules for cutouts in tops of joists eg position and depth as a percentage of overall joist depth. I would consider putting metal straps across the notches to avoid any plasterboard nails hitting the pipes.
TIA
Phil