How to install a box in hole that's too big

[Itai]

Hi All.

I have to replace the winder box for my roller shutters. The old box was larger at approx. 14.5cm high, by 9cm wide. The new box is 11cm high x 7.5cm wide. Photos of the box in the space, and empty space below:

There is only a stud to attach to the left and below. Nothing above or to the right. The previous one was only attach on the left and bottom, so that seems fine. But what I'm not sure how to do is patch the hole to the right and above. One idea I've had is to attach a piece of pine to the wood below and attach the box so that pine. A 19mm piece of pine just fits below. But it won't fit to the left of the box so I can't do the same there.

What I was thinking instead, is to attach the box directly to the stud on the left and then attach this to the right of the box to fill the space so that's it's easier to plaster over https://www.bunnings.com.au/macsim-72-x-100-x-10mm-black-packing-shim_p1044804. Can I drill through these and secure them? Can these take some load if I attached it to the wood on the left, and then attached the box to it?

Does anyone have any smarter ideas?

On another note, once I opened up that space, I found a ton of long grass and one or two pieces of paper packed into there. There were no animal droppings though. What could that be? Rats nest?

Thanks

Regards

Itai

[Shane]

Have you got some spare plasterboard? I'd attach the box directly to the stud then use some spare plasterboard to fill the holes, then patch. https://www.workshop.com.au/t5/Whole-of-House/An-easy-way-to-repair-holes-in-plaster-walls/m-p/8318

[MikeTNZ]

Hi there Itai,

I totally agree with what Shane is saying below/above?

As an electrician, I have to say that most "flush-boxes" in behind walls only screw to a stud, they aren't fully surrounded by timber, it just holds them to the wall

At the same time, I think you need to address that seemingly large open space in behind your wall, it could be a place for birds or vermin to live, possibly look at getting some plywood or the like for the other side of the wall, mice and rats love to chew copper cables, to keep their teeth short, birds nesting in there can be a fire hazard you don't really need.

Let us know if you need any further advice.....

[Itai]

Hey Mike. Thanks for the reply. How would I seal up the space with plywood? Would that involve removing the current plasterboard to gain access?

[Itai]

Hey Shane. Thanks for the tip. I didn't see these replies before I patched it (for some reason sometimes I get it immediately, and sometimes it's a daily update).

I have already installed it, but now just need to patch it. I was thinking of simply using a bunch of poly filler or gap filler. The gap on the right is only a few mm. The gap on top is probably around 7-12mm or so. Would I need to do the method of glueing the two bits of plaster on the inside, or could I get away with poly filler?

For the bits with wood, I suppose I could attach some drywall there, but I worry it will be further out then the rest of the wall...

I am waiting for the cover plate to arrive for the box so see how it will fit. I think it might be also ever so slightly at an angle vertically.

Regards

Itai