Remove old back box?

[Croftie]

Hi,

Need to fit a deeper back box to install a dimmer switch in a bedroom but not sure how best to remove the old one. It's a partition wall and the other side is the landing. The current back box is not screwed in but looks like it's pushed into a blob of plaster. What's the best way to get it out and remove some of the plaster in the back to get enough depth without damaging the wall?

I've got this Dry Lining Plasterboard Box so installation of the new box should be easy just worried about putting a hole in the wall.

Thanks.

 

[sparkwright]

Firstly, before you start making any damage, have you considered fitting a white spacer between the wall and the switch?

These are about 7mm deep, and of the same profile as a regular light switch.

Might save your wallpaper.

No doubt someone will find you a pic.

 

[Croftie]

I have yep, want it flush and the dimmer needs 35mm so it would stick out quite far. It needs redecorating so that's not an issue.

 

[sparkwright]

Ok.

By partition wall, do you mean lath and plaster or plasterboard?

Or something else?

 

[Croftie]

Yes No idea will have to go google lath and plaster

It's not a brick wall so presumed it was plasterboard, not heard of lath and plaster.

 

[Croftie]

Right I don't think it's lath and plaster.

 

[sparkwright]

Lath and plaster was common in houses built before WW2, I would estimate.

It is thin strips of wood nailed horizontally to timber framework, then plastered over.

 

[sparkwright]

You need to carefully cut around the old box and gently prise it out. And see what you end up with.

 

[Croftie]

Was built in the 70s I think, it's quite thin as well about 60mm total, guess it would be a bit thicker than that wouldn't it if it was Lath and plaster. The edge of it looks like plasterboard anyway.

Will give it a go tomorrow hopefully then if not next weekend, wish me luck haha. Thanks sparkwright.

 

[333rocky333]

Tap on the wall, around it, does it sound hollow.
If its plasterboard, I cannot see how a blob of plaster behind it would have worked,
Partition walls can still be a form of brick and id say its chased deep and then squashed onto a layer of plaster.
Id use a thin tool, or work round with a small drill, to cut out round the edges of the box, to get some movement then it will likely pull forward from the bottom edge, mind the cable.
I dont think a dry liner box will be much good

 

[Iggifer]

If it’s 60s it’s not likely to be lath and plaster. More likely a single skin of block. How hard that block is may vary.

If you just get a sharp Stanley knife blade all the way around the edge (avoiding the cable carefully) then it I’ll just be the bonding at the back of the box holding it in and you should be able to tap it free.

Breaking any plaster off that’s made it’s way into the box will help.

You’ll probably need to employ the same method to re-fix the new box as at 60mm with a 25/35mm KO, you’re running out of wall to fix into and may well drill through to the other side

 

[Iggifer]

Tap on the wall, around it, does it sound hollow.
If its plasterboard, I cannot see how a blob of plaster behind it would have worked

Unlikely to be a stud wall if it’s mucked in I would have thought. There’d be nothing to muck it into.

Could be those horrible insulated blocks, had to muck a load of boxes in to those last week

 

[sparkwright]

60mm thick wall?

Oh dear.

This could be 'egg box' type wall, or the similar type where there is a central board with a board either side - like a sandwich.

Those walls can be a pain.

Find out what it is, and we can advise.

 

[Tigercubrider]

try what is said above, but if you get stuck, and if you can get away with a small hole next door, drilling a small hole through might allow you to shove a rod through and whack it enough to dislodge the box.

 

[Croftie]

hmm the plot thickens then. Ok will investigate TY.

It does sound hollow. Just checked the power socket bellow and it has a deeper back box installed in the same way. A deeper box for the light switch as well would of been good!