Drilling holes for water and electricity in floor joists?

[ravsqi]

I'm working on building a bathroom in the basement of a vacation home (a west coast cabin from '66). My idea is to run PEX (pipe-in-pipe, 25mm) and flexible conduit 16mm for electricity through the wooden joists. Most of the beams are about 155x55 + an extra board as shown in the picture at 25x55. The joists are spaced at 60 cm center-to-center and span 5.1m.

Now I'm considering whether it's best to go through the extra board or if I should go closer to the middle of the main beam according to https://www.traguiden.se/konstruktion/konstruktiv-utformning/stomme/bjalklag/barformaga--bjalklag/

Can the extra board have any further impact on the strength?

Thanks in advance!

 

[Emil_K]

Drill where you want, where it's easiest. If the floor structure is so narrowly dimensioned that a bunch of drill holes would affect the load-bearing capacity, then maybe you should consider placing furniture along the outer walls as well.

 

[prototypen]

In the middle of the main beam is best, but as Emil writes, it will hold wherever you drill, they are relatively small holes, worse if you are going through with a 110 sewage pipe.

Protte

 

[ravsqi]

It was clear where I can drill!
Can someone answer regarding the extra rule, does it do anything for the strength?

 

[Emil_K]

It depends on how it is mounted in the floor structure. However, it neither helps nor hinders if you drill into it or not, except that you will have to drill through more wood.