Patching up holes in chipboard flooring

[Gess]

We need to repair a couple of holes in chipboard flooring which is laid on engineered i-joists. Do you have any advice on how to support the square edges of the new chipboard pieces given the nature of i-joists? Unfortunately it is unclear to us how to attach support/noggins to these joists. What would be the safest and more sustainable way to do that? (photo 01)

To give more context:
We are renovating our en-suite. We made the hole to do some pipe work and noticed a bit of mould (could have been caused by a previous leak). We would actually like to cut a little bit more of the existing chipboard to remove the affected area.

In the other photo (02), While cutting the hole, the blade also got a bit in the flange. The damaged joist runs only across the length of the en-suite room, approx 2.4 meters. The cut is about 40cm from the edge of the joist. Is it safe to leave it like that or should we do something about it?

 

[DAZB]

An easy method is to cut small lengths of lat or 22mm ply around 6 to 8 inches longer than the opening and slip them in underneath so they have an equal underhang and fix through the chipboard effectively creating 2 underslung bearers to fix a new piece of flooring to. As for the cut it is not a real problem and could be filled with a thin packer and some foaming glue or similar.

 

[Gess]

Thank you, this is very helpful. Do you think that using 22mm chipboard or 2 by 6 / 2 by 4 inches timber instead, will offer the same/optimal support?

 

[DAZB]

It is a common way of repairing access holes so quite alright with either choice.

 

[Gess]

Got it, thanks again)