Channeled plasterboard - repair

[Jupiter01]

I have a dot-and-dab wall which I was trying to pass a cable behind. However, the plasterboard is stuck so closely to the block wall that the void is too narrow to pass the cable.

I had to cut a vertically channel through the plasterboard to place my cable into. I have gone all the way through the plasterboard and not cut into the blocks. As stated above, there is hardly any gap between the back of the plasterboard and the block. I am quite used to using easifill and wondering if I can use it here to make good, before painting. I don’t want it to crack after a while. Can you please advise.

Thanks in advance.

 

[Wayners]

Lash on a quality PVA up the channel.
Cut some 9mm plasterboard to fit. Seal the dry cut edge off the 9mm plasterboard with the pva.
Dot and dab it in. Fill and smooth off. You can use the easyfill to stick and fill. It won't crack.

You can also use 6mm elements board if the 9mm is too thick

 

[lostinthelight]

If its only a chase width and pb that close to the wall, by the time you take the depth of conduit there wouldn't be enough depth for strips on top before filling I would have thought + you have to have a piece kicking around and narrow strips of board are flimsy to cut and handle

 

[Jupiter01]

Even the 6mm board may be a struggle in this space. The 2.5mm T&E cable itself is reasonably chunky. Would I be okay to use diluted PVA and easy fill straight over this? I could apply a few coats of easyfill to build up the depth.

Would expanding foam help?

Thanks for your help.

 

[lostinthelight]

I wouldnt use foam, it would leave weak surface under thin coat of filler.

 

[Wayners]

Should not use foam around cables. I never used filler over cables as it's seems to show through wall. Cables should have air gap around so I always bridged over.
Many insists on a sheath over so wire can be pulled out and replaced, so i would dig wall back to allow for cable plus sheath.
Where this was not done I'd bridge cable with a thinner board