Wet plaster vs (Dry) plasterboard

jonneymendoza

jonneymendoza

jonneymendoza

Caporegime
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Lorville - Hurston
Hi. i have just got my first fix done on my electric and looking for some advice on which plastering method to use.

I asked my electrician and he told me that wet plastering is what i shoudl go for as all the socket boxes he installed sit flush inside the brick wall when he did some chasing.

His worry is that if i go for using a plasterboard, the plasterboard will come out thicker than the existing plaster i have(looks to be an old school wet method) as to aply the plasterboard to the wall, you do so using dot and dab which creates a gap between the wall and the plasterboard.

Electrician doesnt wanna go back and cut stuff up again adding say a extension column as its more work etc again and he just done chasing etc into the main brick work and i kinda agree with him but wondering if there is other ways of using plasterboard as its quicker to apply and cheaper too.

Walls in question

20230223_103004 by Jon Richy, on Flickr

20230223_102950 by Jon Richy, on Flickr

20230110_103707 by Jon Richy, on Flickr
 
Are you removing all the existing plaster?

Rather than "dry" plastering the terminology you're looking for is dot and dab plastering, which is what most people do these days. Put dots of plasterboard on the wall then dab the plasterboard on.

Its a lot quicker and easier than hardwall and finishing plaster. Some debate if the latter has a better finish.

Dot and dab with 12.5mm plasterboard will come out about 25mm normally. Most competent sparkies /trades would be aware of this...


If your house is pre 1930s and not a cavity wall then there is the seperate consideration of lime plaster and breathability.
 
I'm not electrician but does it matter if there is a gap between the back box and the front plate; can longer screws just be used? There seems to be enough cable in the boxes for that? I may be talking nonsense though....
 
Normally in that situation if the existing plaster is solid you would patch in the holes(use some stabilising primer on the bricks) then give the walls a skim coat all over if necessary.

Dot & Dab, I would want to be fixing it to the bricks and not the existing plaster, also you will have to take off the skirting and then put back.

@FNG is correct about longer screws so might not be an issue.

I assume you are getting a plasterer in? He would skim those walls in no time. If you plasterboard you still need to skim it or use taper edge boards and fill the joints(they do this in the US).

If you are at the point where the existing plaster is falling off the bricks, then a good idea to take it off. Once you are back to brick you can Dot & Dab insulated board(cheaper if you do much of it yourself) or float and set.
 
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Yes the existing plaster will come off as if you even blow at it. It falls off!

So if the plaster board is not as flush as needed for the switch box, we can just use longer screws for the 2nd fix?

And yes it's pre 1930s
 
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To be honest if all the plaster is coming off i would have been doing all that before the first fix. You can also use 9mm plasterboard to get it a bit thinner but the dot depth will depend on how true your walls are! Some of our extension where it meets the existing house has about a 2" cavity between the plasterboard and brick! A room wall like that shouldn't be anywhere near as bad but you migt end up with some extra thickness from there.
 
I don't get why you can't just chuck a load of plaster at it, like it has been for 50+ years?
 
Gav_r26 said:
To be honest if all the plaster is coming off i would have been doing all that before the first fix. You can also use 9mm plasterboard to get it a bit thinner but the dot depth will depend on how true your walls are! Some of our extension where it meets the existing house has about a 2" cavity between the plasterboard and brick! A room wall like that shouldn't be anywhere near as bad but you migt end up with some extra thickness from there.
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The decision to take it all off was recent tbh as I thought we could just patch it up. I'm all new to this!
 
The obvious solution here is to pad behind the boxes if you choose to use dot/dab plasterboard so they sit far enough forward. They should just be fixed in with screws and plugs.

That said if you do board it then you could probably just switch them out for drylining boxes instead.

If it were me based on those pictures I'd just get it patched and skimmed.
 
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FNG said:
I'm not electrician but does it matter if there is a gap between the back box and the front plate; can longer screws just be used? There seems to be enough cable in the boxes for that? I may be talking nonsense though....
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Would this do the trick? https://www.toolstation.com/extension-stud/p79641

Also, does the socket face need to be close to the back box for safety reasons etc?
 
If the plaster has blown in lots of places (tap it and see if it sounds hollow) then you'll ideally either remove it all, cover it in SBR primer, then apply hardwall and skim, or if most of the plaster is ok, patch and skim.

I'd be tempted in that situation though to overboard (mechanical fixings as well as dot and dab) and replace / adjust the boxes 8f necessary, then you can get away with taping and filling the joins, priming, and painting, rather than skimming the whole lot.

If it was me though, I'd strip it all back to brick with the SDS drill and plaster, but I just like plaster.
 
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Take it off, if its an uninsulated external wall you could use insulated plasterboard dabbed on but they add a bit of thickness. Your electrician sounds like an unhelpful one to me.
 
Survey it on a wall by wall basis for any blown plaster. External walls is a no brainer to insulate while you are this stage of your renovation. You've already done the worst job there is renovating, taking the lat and plaster ceilings down. You may want to look at the cracks in the 1st floor bay window. They usually come from poor install of replacement windows in the groundfloor bay.
 
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