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.

On Wednesday, 24 July 2019 10:07:35 UTC+1, Scott wrote:
Could the plasterer add 1-2mm to the plaster to create a level finish?

Or 3mm, so all the boxes disappear completely?

Owain

Mathew Newton brought next idea :
Will the plasterer be cursing me for this for making his job harder, risking
damage to his tools etc?

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.

On 24/07/2019 09:55, Mathew Newton wrote:
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.


Speak to the plasterer. Obviously. Get his agreement.

Bill

On Wednesday, July 24, 2019 at 10:07:35 AM UTC+1, Scott wrote:

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

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.

On Wednesday, July 24, 2019 at 12:58:40 PM UTC+1, Bill Wright wrote:

Speak to the plasterer. Obviously. Get his agreement.

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.

On 24/07/2019 13:04, Mathew Newton wrote:
On Wednesday, July 24, 2019 at 12:58:40 PM UTC+1, Bill Wright wrote:

Speak to the plasterer. Obviously. Get his agreement.

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.

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.

On Wednesday, July 24, 2019 at 1:42:18 PM UTC+1, wrote:

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.

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!

On 24/07/2019 14:17, Mathew Newton wrote:
On Wednesday, July 24, 2019 at 1:42:18 PM UTC+1, wrote:

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.

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!


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

Bill

On Wed, 24 Jul 2019 05:01:23 -0700 (PDT)
Mathew Newton wrote:

On Wednesday, July 24, 2019 at 10:07:35 AM UTC+1, Scott wrote:

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

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

It seemed crystal clear to me.

On Wed, 24 Jul 2019 17:10:19 +0100, Rob Morley
wrote:

On Wed, 24 Jul 2019 05:01:23 -0700 (PDT)
Mathew Newton wrote:

On Wednesday, July 24, 2019 at 10:07:35 AM UTC+1, Scott wrote:

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

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

It seemed crystal clear to me.

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

On Wednesday, 24 July 2019 17:56:12 UTC+1, Scott wrote:
On Wed, 24 Jul 2019 17:10:19 +0100, Rob Morley
wrote:

On Wed, 24 Jul 2019 05:01:23 -0700 (PDT)
Mathew Newton wrote:

On Wednesday, July 24, 2019 at 10:07:35 AM UTC+1, Scott wrote:

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

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

It seemed crystal clear to me.

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

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.

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

On 24/07/2019 09:55, Mathew Newton wrote:
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.


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

--
Adam

ARW presented the following explanation :
Sink them so that they are flush or just below the surface.

+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.

On Thursday, 25 July 2019 21:57:02 UTC+1, Harry Bloomfield wrote:
ARW presented the following explanation :
Sink them so that they are flush or just below the surface.

+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.

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

On 25/07/2019 21:56, Harry Bloomfield wrote:

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.

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.

Mike Clarke Wrote in message:
On 25/07/2019 21:56, Harry Bloomfield wrote:

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.

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.


Ah finally ! A voice of reason :-)
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 26/07/2019 22:50, Jim K.. wrote:
Mike Clarke Wrote in message:
On 25/07/2019 21:56, Harry Bloomfield wrote:

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.

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.


Ah finally ! A voice of reason :-)


You cannot reason with a plaster.

--
Adam

On Saturday, 27 July 2019 16:26:00 UTC+1, ARW wrote:
On 26/07/2019 22:50, Jim K.. wrote:
Mike Clarke Wrote in message:
On 25/07/2019 21:56, Harry Bloomfield wrote:

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.

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.


Ah finally ! A voice of reason :-)


You cannot reason with a plaster.

And on that basis I figured I might as well make the possibly-an-issue-possibly-not into a simple non-issue and went round the boxes I'd done so far and sunk them into the blocks slightly so they are no longer sitting even the slightest bit proud. The blocks were smooth and a so a bit tricky to scrap off just a mm or two but I found the easiest/quickets way was to roughen up the surface with a scutch chisel and then scrape this roughness off with a straight chisel to provide the required recess.

I know what'll happen now - I'll casually mention the subject to the plasterer over a brew and he'll tell me he prefers the backboxes slightly proud as it gives him something to plaster up to for a neater finish... ;-)

On 30/07/2019 23:06, Mathew Newton wrote:
On Saturday, 27 July 2019 16:26:00 UTC+1, ARW wrote:
On 26/07/2019 22:50, Jim K.. wrote:
Mike Clarke Wrote in message:
On 25/07/2019 21:56, Harry Bloomfield wrote:

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.

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.


Ah finally ! A voice of reason :-)


You cannot reason with a plaster.

And on that basis I figured I might as well make the possibly-an-issue-possibly-not into a simple non-issue and went round the boxes I'd done so far and sunk them into the blocks slightly so they are no longer sitting even the slightest bit proud. The blocks were smooth and a so a bit tricky to scrap off just a mm or two but I found the easiest/quickets way was to roughen up the surface with a scutch chisel and then scrape this roughness off with a straight chisel to provide the required recess.

Depending upon the type of block, other ways can be easier, but messier.
When building our conservatory, the dwarf walls and partial full-height
walls were built with lightweight blocks on the inside and a router with
an old bit made short work of recessing back boxes and chasing cables
into the walls.

SteveW