Drilling joists to run shower waste.

[Restoration man]

I am refitting a shower room in my house and moving the shower. There will be two options for the waste straight out a wall and tie in to existing external drain or drill through 3 joists and tie into existing toilet 4" pipe.

The house is 90 year old. Joists are 8" deep pitch pine. My plumber who is a traditional country plumber and is very competent in various trades says drilling these joists for this purpose is absolutely not a problem.

Ive worked with him on a lot of projects on the house and I really rate him but I'm scared on this one. Think we're putting a 2" hole through the middle of them.

Just want a second or third opinion.

One option I have thought around all of this is to build a raised timber frame to put the shower tray on this would allow the shower waste to be run over the top of the joists and no drilling required.

Cheers

 

[23vc]

You are definitely not supposed to drill that big but seen it loads of times waste pipes notched/drilled without anything collapsing
I would take them out the wall every time as more pipework accessible without having to get under the floor. I also fit a t with an access cap instead of a 90 bend where it goes out the wall so you could access it (if your using solvent weld)

 

[John D v2.0]

Nothing will collapse, but your floor will become more bouncy.