Running pipes though joists

[ABN]

Hi

Remodeling the bathroom and trying to hide all the pipe work. Need to try to run the bath waste pipe across the room and hence through all the joists. This will be very close to where the joists are supported by the outside wall.

So the question is how large a hole can I cut in the joists, will be at various levels to allow for the fall of the pipe. The joists are nominaly 2" thick and set upto 400mm apart.
Will a 1 and a half inch hole weaken the joist to much?
and if so is there any easy way to strengthen them to allow holes of that size.

 

[splinter]

You cannot cut that much out of the joists.If you think about it you would have to notch the joists making each notch progressfully deeper ,unless you was going to drilla hole in the centre of the joist and put the waste pipe in in short lengths.I have seen some regulations regarding this subject on a forum somewhere

 

[ABN]

unless you was going to drilla hole in the centre of the joist

Thats what I intended to do.

put the waste pipe in in short lengths.

Hmmz hadn't thought about that problem. The simple things are so easy miss at times

But if it is allowed I'm not to worried by using lots of short bits allthough it increases the number of joints and hence the likely hood of a leak.

 

[splinter]

This is what I found :-A hole in the centrer of a joist should not be more than 0.25 than the depth of a joist . A notch should not be more than 0.125 than the depth of a joist .There are also maxium measurements given from the ends of the joists given from the end of the joists,wich I have gone and forgot ,but it looks like youare going to have tobox the pipe in so they don't matter in this case

 

[ABN]

Darn back to plan B then (only wish i had a plan B)

Thanks for the quick reply