Is a small gap in bathroom floor under bath OK

[JP_]

I have almost enough floorboard to cover the space under where the bath will go, so if I can avoid buying another sheet I will. This will be covered, and I will shove insulation all under the bath to help hold warmth, so there should be no drafts coming up. Also, I guess a gap does mean if there is ever a leak down edge of bath, water will go to the subfloor and evaporate rather than soak into floorboards and rot everything ...

In the space to the left of the bath (black mark on wall marks approx bath edge) will likely be a vanity unit, and I plan to put 5mm ply over the floor before vinyl sheet. So this area should not really be stepped on if the vanity is close.

I do need to order one more sheet of Chipboard Flooring ... but should I just buy 3 so it goes to the wall (these 2 boards were left over from previous room)? Because of pipes there is not a joist against the wall though, but I could add some timber to the top of the wall plate on the right. It all feels solid to walk on and not screwed down yet.

 

[oldbutnotdead]

First thing, chipboard as a bathroom floor is a poor choice due to its rapid deterioration if it gets wet (example- you leave the bath running and it overflows for half an hour. Timber floor will dry out. Chipboard floor will need replacing unless it's the heavy (green tinged) waterproof variety.
After that, don't worry about gaps in the floor under the bath, there are usually loads of holes from pipework etc. Just make sure you fit the waste etc properly so it doesn't leak and use appropriate methods so you don't get water trickling down behind the bath from shower splash.