- Thread starter shobo
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If it’s lath and plaster you won’t be able to chase into it, you might be able to pull cable through behind the laths if there’s a void.
It’s also tricky to fit back boxes and sockets - best way I’ve found is to attach the back box to short lengths of laths, sticking beyond the back box. Cut the hole then carefully screw though the cut off laths and fix to the laths attached to the back box to make everything rigid again.
Permissions wise probably a grey area, minimal damage and disruption I would say.
It’s also tricky to fit back boxes and sockets - best way I’ve found is to attach the back box to short lengths of laths, sticking beyond the back box. Cut the hole then carefully screw though the cut off laths and fix to the laths attached to the back box to make everything rigid again.
Permissions wise probably a grey area, minimal damage and disruption I would say.
Flyfisher
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Yes, lath and plaster depends on a void behind the laths for the plaster 'nibs' to form and therefore hold the plaster against the laths. Chasing a channel into lath and plaster is likely to be quite destructive. Any hammer-and-chiselling will almost certainly cause lumps of plaster to be 'bounced off' the laths as they flex. Less destructive would be to use something like an angle grinder to cut through the plaster and laths, but even then you'll likely end up with unfixed ends of lath that could move and further crack the plaster. All in all, not to be recommended. As pointed out above, if the walls really are lath and plaster then it might be possible to run cables behind. This would only require small access holes at each end of a run.
I've added sockets to a room with lath and plaster walls but was fortunate that it also had a suspended floor. So I mounted the socket into a surface box screwed to the skirting board. This method avoided any damage to the walls. I appreciate this might not always be practical but mentioned it as an example of other possibilities.
I've added sockets to a room with lath and plaster walls but was fortunate that it also had a suspended floor. So I mounted the socket into a surface box screwed to the skirting board. This method avoided any damage to the walls. I appreciate this might not always be practical but mentioned it as an example of other possibilities.
Zebra
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This is my favourite method. It's tricky and painstaking but does less damage to the wall than any other I've ever seen used.
Let's say you're doing a vertical run downwards from the ceiling to a socket: you make a hole with a flat drill bit at the top of the wall, trying to get between two laths rather than cut one. You insert drill bit through the hole and drill through the wall plate (the horizontal timber at the top of the wall, the top of which will hopefully be visible if you've got the floorboards up above). A 16mm/20mm/25mm hole, depending on how many cables you've to drop into the void. Shove a bit of draw-wire through the hole. (a piece of single core cable is good for this).
Get a bit of string with a weight on the end and drop it into the hole, to see how far the void extends before you have a noggin (another horizontal timber). Make a hole in the plaster, preferably between laths not cutting through them, above and below that noggin, and drill vertically* through the noggin, either from above or below, depending on what seems to work best. Shove a bit of draw-wire in there too. Use your piece of string to join that draw-wire to the upper draw-wire.
Continue in like fashion, or something like that, until you reach your socket position.
It is best to plan sockets so they're beside vertical studs, then use a metal backbox, drill holes in the side of it and screw it to the stud.
Then it's like "sewing" to join up all your bits of draw-wire through noggins and in voids, go above to join the cable on, and pull it down. Naturally it comes off and you have to have to pull it out and reinsert the draw-wire. All involves much running up and down the stairs, much tape, and maybe a bit of swearing.
But the advantage is that all you have to make good are a series of holes, and not a complete chase. Hopefully also, you've not cut any laths except around the socket!
Sigh. I miss being a spark.
Unfortunately can't comment on whether this is permissible if listed.
* Obviously you can't do it perfectly vertically, it will always be on a slight diagonal, but long drill bits, or drill bit extenders, mean that you can do it from further away, lessening the angle.
Let's say you're doing a vertical run downwards from the ceiling to a socket: you make a hole with a flat drill bit at the top of the wall, trying to get between two laths rather than cut one. You insert drill bit through the hole and drill through the wall plate (the horizontal timber at the top of the wall, the top of which will hopefully be visible if you've got the floorboards up above). A 16mm/20mm/25mm hole, depending on how many cables you've to drop into the void. Shove a bit of draw-wire through the hole. (a piece of single core cable is good for this).
Get a bit of string with a weight on the end and drop it into the hole, to see how far the void extends before you have a noggin (another horizontal timber). Make a hole in the plaster, preferably between laths not cutting through them, above and below that noggin, and drill vertically* through the noggin, either from above or below, depending on what seems to work best. Shove a bit of draw-wire in there too. Use your piece of string to join that draw-wire to the upper draw-wire.
Continue in like fashion, or something like that, until you reach your socket position.
It is best to plan sockets so they're beside vertical studs, then use a metal backbox, drill holes in the side of it and screw it to the stud.
Then it's like "sewing" to join up all your bits of draw-wire through noggins and in voids, go above to join the cable on, and pull it down. Naturally it comes off and you have to have to pull it out and reinsert the draw-wire. All involves much running up and down the stairs, much tape, and maybe a bit of swearing.
But the advantage is that all you have to make good are a series of holes, and not a complete chase. Hopefully also, you've not cut any laths except around the socket!
Sigh. I miss being a spark.
Unfortunately can't comment on whether this is permissible if listed.
* Obviously you can't do it perfectly vertically, it will always be on a slight diagonal, but long drill bits, or drill bit extenders, mean that you can do it from further away, lessening the angle.
CliffordPope
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Take a flat piece of wood of a width that will just pass, diagonally, through the hole cut for the pattress box, and attach a large screw in the middle as a handle. Then feed it into the hole and pull it firmly against the back of the laths/plaster, and screw it securely through the ends of the cut lathes so that it is held tightly. You could apply foaming adhesive before pulling it tight for added strength.
Then unscrew the big screw and fit the pattress box in the normal way.
Then unscrew the big screw and fit the pattress box in the normal way.
Flyfisher
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. . . or an old fishing rod 
Feltwell
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Cable rods are both a) damn useful and b) cheap! I'd advise anyone doing any running of cables to invest in a set, a cheapo one like the below has been fine for me, often I end up taping the cable to the rods in order to pull it through.
https://www.ebay.co.uk/itm/10M-Cabl...695851&hash=item51a090e16f:g:EBsAAOSwYGFUtoPs
There are some really cheap sets with 1' long rods, which look too short to be of any use really, and just annoying and less flexible when joined up.
As with drain rods, the golden rule is if you need to turn the rod while feeding it through always turn it clockwise, never anti-clockwise, as if you do that the joints can unscrew and leave half the rod behind!
I like Zebra's method above by the way - looks to be the most minimally destructive. I've been lucky enough here that where I've had to put sockets on lath & plaster walls they are in the attic and are a "one-sided" wall - by crawling round inside the eaves I can get to the reverse of the wall, which is open with no L&P on it.
https://www.ebay.co.uk/itm/10M-Cabl...695851&hash=item51a090e16f:g:EBsAAOSwYGFUtoPs
There are some really cheap sets with 1' long rods, which look too short to be of any use really, and just annoying and less flexible when joined up.
As with drain rods, the golden rule is if you need to turn the rod while feeding it through always turn it clockwise, never anti-clockwise, as if you do that the joints can unscrew and leave half the rod behind!
I like Zebra's method above by the way - looks to be the most minimally destructive. I've been lucky enough here that where I've had to put sockets on lath & plaster walls they are in the attic and are a "one-sided" wall - by crawling round inside the eaves I can get to the reverse of the wall, which is open with no L&P on it.
Flyfisher
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Owain said:
True, but if there is something bare and live in such areas then you have another serious problem. If in any doubt there's always the 'off' switch on the consumer unit :wink:
Zebra
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I've had another thought, that the bulk of my experience is with turn of the century London houses, which may be lath and plaster on internal walls, but invariably masonry external walls.
Shobo, is the house about which you are enquiring of a timber frame construction? In that case, drilling into the frame might be something you'd rather not do.
Shobo, is the house about which you are enquiring of a timber frame construction? In that case, drilling into the frame might be something you'd rather not do.
Flyfisher
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Owain said:Consumer unit?
Collection of metalclad fuseboxes and a main switch that looks like two 5a tumbler switches with linked dollies on a block of wood ...
Ah, real 'period' electrics then? We also had a right mess of boxes and switches, including a wooden fusebox complete with porcelain fuses (many with multiple lengths of fusewire in them :shock: ) . . .
I soon had it all tidied up though - can't be doing with vintage electrics I'm afraid.
CliffordPope
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fernicarry
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That's quite scary.
Flyfisher
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Hmm - 'interesting' use of terminal strips. :shock:
A bit too 'interesting' for my liking. :?
A bit too 'interesting' for my liking. :?
Zebra
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What, one wonders, does a circuit described as "big chimney" do?
CliffordPope
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Simple - the space inside the big chimney is more like a small room, and has several wall sockets in it. There's no ring-main. Each socket or close group of sockets has its own fused spur.