Wetroom job

[mikethetile]

Hi John, You know I don't include you in my list of plumbers butchering joists!

Our standard codes for dimensional lumber state it's OK in the middle third on the vertical dimension, but not within 2" of the lower or upper edge of the board (as John W noted). There is also some infomation about drilling anything within a certain distance of the end of the board (where it has bearing strength). I think this is a no-go within the outermost 18" of the joist. It's also a no-go in the middle third of the span.

For engineered stuff, all bets are off, and the manufacturers have all sorts of do's and don'ts for those.

hi Rob
thanks for explaining the regs so elanquently, you saved me trying to explain our regs
which just happen to be the same

its based on the downward pressure on the floor joist and where the internal stresses lie

woods woods whichever county its used in and is subject to the same stresses and limitations

there are safe zones and critical zones,if you drill through a critical zone you may weaken the joist and lead to its failure

carpenters, plumbers and electricians are taught these principles everone else is told not to drill through a joist unless it is checked and marked out by a competant and authorised person

 

[Rob Z]

Mike, some of the engineered lumbers can't be drilled in at all. A buddy was on a jobsite onetime and the sparkies drilled a bunch of holes in the engineered beam that was installed to carry the load of the addition above. The inspector flagged it and it had to come out. I can just imagine the fireworks over that one.

As a general contractor, I tell all subs onsite - plumbers/sparkies/HVAC - if they want to cut or drill something to see me first, and often times we do it for them.

 

[mikethetile]

Hi Rob
same here with engineered joists, if they need to be drilled it has to go in the specification to the manufacturer, you cant just drill them