Subfloor edge support underneath bath

[mookle]

Hi all! First time refitting a bathroom - would love some guidance re. edge support underneath a bath where the subfloor needs to allow pipework. Some details:

22mm T&G P5
joists A & B are 2x7, 2.25m span
joist C is 3x7, 3.5m span
the centers in the pic are approx 380mm, the rest of the (tiny) room is on 270mm centers

The plan is to offset the P5 so the mid-point is roughly over the water pipes, and add edge support to the left of the waste pipe in the form of a 2x4. My thinking was the holes needed to allow the pipes will weaken the P5 right where it's most needed, so support (edge or otherwise) would be a good idea.

Am I barking up the wrong tree here? Is support even needed? If so, is 2x4 too thin? Is offsetting the P5 pointless? It certainly would be easier to cut holes from the edge of the board, but I thought maximising the material resting on the end joist would be a good plan...

 

[foxhole]

Should not need additional support sub floor, small section of ply under legs for the bath (or your 2x4) will spread load enough .

 

[mookle]

Thanks foxhole. I suspected I might be overthinking things! I always tend towards over-engineering things when I'm not sure

 

[stevie888]

When I remodelled my daughters place there was an old cast iron bath that sat on 4 feet maybe 30x50 kjust down on the boards. It must have weighted north of 200kg empty. It went back on 2 bits of 6x2 spanning the joists. Over engineering good!!