Install electric box before or after hard plastering? Advise needed

Jonny Vee · 31 May 2020

Electrician coming down during the week and requested me to start making all the chase and install boxed where required.

As most of my walls need a completely new plastering ( Hard plastering) and at the moment I have brick exposed. My question would be. Do I have to install the boxes taking into account 10mm hard plastering and leave the box out of the wall to have it flush once the plastering is done or was it better to have all plastering done and chase later? This would end up doing work twice.

Any advice would help

conny · 31 May 2020

Put the boxes onto the walls now. Is the electrician going to do the wiring before the plastering? May seem like a daft question but it has been known for it to happen the other way round.
The plasterer will plaster up to the front edge of the box so your socket outlets/switches are able to sit flush against the wall. You don't need to take any plastering depth into account.

Jonny Vee · 31 May 2020

conny said:
Put the boxes onto the walls now. Is the electrician going to do the wiring before the plastering? May seem like a daft question but it has been known for it to happen the other way round.
The plasterer will plaster up to the front edge of the box so your socket outlets/switches are able to sit flush against the wall. You don't need to take any plastering depth into account.

I'm talking about hard plastering. Electrician is going to do first fix now. A plasterer told me a whe ago that He was going g
After the electrician but my question is if you install boxes now. After the hard plaster all the boxes will be sitting recessed and long screw are needed. I was wondering how was the correct procedura when you have the hard plastering completely out and need to do it.

mattylad · 31 May 2020

What is "hard plastering"?
All plaster starts as soft and becomes hard when it dries.

sparkwright · 31 May 2020

By hard plastering I suspect he means a 'render' (or hardwall or bonding coat), then a skim finish coat.

So NOT dot and dab.

Jonny Vee · 31 May 2020

sparkwright said:
By hard plastering I suspect he means a 'render' (or hardwall or bonding coat), then a skim finish coat.

So NOT dot and dab.

Yes. I mean the rough strong coat before the finishing.

sparkwright · 31 May 2020

Gio I said:
I'm talking about hard plastering. Electrician is going to do first fix now. A plasterer told me a whe ago that He was going g
After the electrician but my question is if you install boxes now. After the hard plaster all the boxes will be sitting recessed and long screw are needed. I was wondering how was the correct procedura when you have the hard plastering completely out and need to do it.

Some words and letters missed out in this.

What are the long screws for?

DetlefSchmitz · 31 May 2020

Talk to the plasterer and agree how you should fit the back boxes, bearing in mind it depends on their depth, and it is unlikely they are all the same depth.

sparkwright · 31 May 2020

In most cases you should know where the finished surface of the plaster will end up, for example flush with the edge of a door lining, and a long length of batten be placed against the wall to indicate where the finished surface will be.

conny · 31 May 2020

By 'hard plastering' you mean a base coat which is then finished with a smooth topcoat, commonly referred to as 'board finish.
If the boxes are recessed after the base coat then your plasterer is putting too much on the walls. It only needs to be about 1" (25mm) maximum, which is the depth of a standard back box.
In my experience the base coat 'usually' comes to the front edge of the back box or just below and then the top coat is about 2 mm-3mm thick to come to, or just past, the front edge. This helps to ensure the socket/switch face sits flush against the wall. Light switch back boxes are not quite so deep but I've never found the need to use longer screws.

crystal ball · 31 May 2020

There is a trend for fitting deeper boxes to accommodate dimmers, USB, smart switches etc

Jackrae · 31 May 2020

Make sure the boxes don't stand too proud so that the plasterer gets an even chance to fill them up

Is there a gizmo on the market for fitting into standard single and double boxes to ease recovery or even prevent them being filled with plaster.

RF Lighting · 31 May 2020

Jackrae said:
Make sure the boxes don't stand too proud so that the plasterer gets an even chance to fill them up

Is there a gizmo on the market for fitting into standard single and double boxes to ease recovery or even prevent them being filled with plaster.

It’s called a bit of cardboard, and is available from most shops.

Jackrae · 31 May 2020

And it can be held in place using the 3.5mm box fixing nuts

conny · 31 May 2020

RF Lighting said:
It’s called a bit of cardboard, and is available from most shops.

I can get you some for free from our cereal cupboard.

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Install electric box before or after hard plastering? Advise needed

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