Leaving backboxes proud?

[Jim K..]

Ah finally ! A voice of reason :-)

[Mathew Newton]

I am currently installing a number of additional sockets, switches etc in advance of a room being re-skimmed. The walls are dot-and-dab plasterboard on blocks and I am finding that in places the 25mm metal backboxes are sitting slightly proud of the plasterboard by ~1-2mm. Will the plasterer be cursing me for this for making his job harder, risking damage to his tools etc?

I could sink the boxes in to the blocks but as things currently stand this will add a fair bit of faff to what has otherwise been a really easy job given the ease with which the holes can be cut in the plasterboard and the cables routed behind it. No chasing into the blocks has been required thus far.

[Scott]

Could the plasterer add 1-2mm to the plaster to create a level finish?

[spuorgelgoog]

Or 3mm, so all the boxes disappear completely?

Owain

[Harry Bloomfield]

Mathew Newton brought next idea :

Yes, plus your accessories will be stuck out above the finished wall surface. They need to be completely flush to the face of the board.

[Bill Wright]

Speak to the plasterer. Obviously. Get his agreement.

Bill

[Mathew Newton]

Given the response so far I obviously haven't made my situation very clear - apologies!

The room is getting re-skimmed after I have done my work, including the new electrics. Thus, whilst my new backboxes might currently be sitting proud by 1-2mm they won't be once the 2-3mm skim is applied. My only concern is whether the proud backboxes make the plasterer's work harder, and not whether I'll have an issue once the plastering is done.

[Mathew Newton]

With the way this project is going the appointing-a-plasterer stage feels almost as far off as selecting-soft-furnishings!

If there's no hard and fast rule about what is acceptable then, yes, it'll come to what the plasterer says. If it's a showstopper for them (unlikely as I imagine plasterers have to deal with all sorts of issues caused by the numerous trades before them) then I'll just go round each proud box and chip sufficient material away from behind them. If I can avoid that faff though I will.

[nothanks]

I've always made sure the backbox is flush with existing plaster or slightly recessed, coiled the cable inside, and then cut a square of thin card to fit inside the box. It makes the plasterer's job slightly easier, avoids getting the box filled with plaster and gives slightly more space for cables.

[Mathew Newton]

Yes, I was planning on doing similar re coverings. I see you can buy them readymade (e.g. 'Blank-It') but I'll make do with cardboard and scissors!

[Bill Wright]

Some types of co-ax take up moisture from wet plaster. Tape up the end.

Bill

[Rob Morley]

It seemed crystal clear to me.

[Scott]

I was puzzled why a protruding steel box would cause more damage to tools than stone, brick or concrete that is commonly plastered over.

[Mathew Newton]

As is probably quiet evident I don't know much about plastering and associated tools, and was thinking perhaps the tools used for doing a skim coat might be of finer quality and more susceptible to damage compared to those required for what I assumed would be a rougher base coat.

If it's a non-issue I won't give it a further thought.

[jrwalliker]

Plasterers will have no problem with protruding back boxes, but the wall may not be so flat where they have worked around them. It is definitely worth filling the box with an offcut of Celotex or foam polystyrene. It makes it much easier to clean out the box afterwards and it makes the plastering go more smoothly.

If the box ends up protruding one or two mm from the finished surface this does not matter because most sockets and switches have a recess on the rear surface.

John

[ARW]

Sink them so that they are flush or just below the surface.

[Harry Bloomfield]

ARW presented the following explanation :

+1

If a box is proud, a plasterer will tend to make the plaster deeper just around the box to get cover, which will show in the finished job. I've seen it many times.

[Mathew Newton]

Now *that* would annoy me. Thanks everyone, will go round and scrape away the blocks of those that are protruding by any amount.

[Mike Clarke]

But the OPs boxes are only 1 - 2 mm proud of the plasterboard. Assuming that there's to be a 3mm skim then they'll be 2 - 1 mm below the finished surface of the plaster and there should be no need for the plasterer to build up extra thickness at the boxes.

[ARW]

You cannot reason with a plaster.