50mm Waste pipe hole size

[Serval]

What hole size would you recommend drilling for 50mm waste pipe that needs to go through a joist?
Joist is 200 deep so a 55mm hole is already a bit over the recommended size for that joist.

 

[Ric2013]

If you're going to go through the joist then it's obvious that the hole has to be bigger than the pipe and that the pipe shouldn't rub (or wrap it in something that will allow it to rub quietly and without abrasion).

As you say, 1/4D is a recommendation - perhaps you can reinforce the joist in some way in order to compensate?

 

[ShaunCorbs]

60mm min you won’t do 50mm in joists

 

[Serval]

you won’t do 50mm in joists

As in you shouldnt attempt to run 50mm pipe through joists?

Or that a 50mm hole is too tight a fit?
If its the latter i was just trying to get a idea of how oversized people usually go to allow for maneuvering the pipe, creating enough fall etc

 

[Serval]

As you say, 1/4D is a recommendation - perhaps you can reinforce the joist in some way in order to compensate?

I was thinking something like this

Or possibly glue and screw 18mm ply either side before drilling through the ply and the joist.

 

[ShaunCorbs]

As in you shouldnt attempt to run 50mm pipe through joists?

Or that a 50mm hole is too tight a fit?
If its the latter i was just trying to get a idea of how oversized people usually go to allow for maneuvering the pipe, creating enough fall etc

Both unless the joists 250mm plus or I joists