Want to add a bath upstairs, just a sink and toilet, need to know the code in Kentucky for floor joist, don't know if what is there now is enough, thanks for any help

Code requires certain live and dead loads be taken into considerations for the design and as long as the design meets those specifications, then it's good. It doesn't say you must have no less than 2x10's spaced 19.2" oc. Truth is your floor support can be 2x4's if the span is short enough.

I do believe the basic half bath falls under the normal 40/10 for live and dead load considerations and that your floor structure must meet a deflection of no less than L/360 using those loads. Where you may have problems is if you are moving walls that may be supporting roof loads or if you would need to notch a joist to run your dwv lines. If notching is the case, start thinking of soffits and tray ceilings in affected rooms below.

It's much easier to figure if what you have would meet the minimum requirements and how to amend it if needed if you posted exactly what you have right now, joist size, spacing and unsupported span as measured from supporting wall or beam below (not existing walls on the joist, but from below) vs trying to list the almost infinite possible variations of sufficient supporting structures.

Hi all...

If looking to install only a toilet and a sink then you will have no issues as long as you run the toilet pipe up in the joist bay that the toilet will be in. Here, no matter the joist size, as long as you don't cut the joist you will be fine. If you can't arrange to get the pipe in the correct joist bay then you will need to let us know how large your joists are.

In terms of the sink, if it is on the same wall as the toilet (usually is) then you may be able to install the drain line to the toilet vent above the floor... again, no joist issues there!

Let us know more here... OK?

Mark