lathe and plaster --- Pulling cable drops---

[tuckermot]

Hi all
I am going to start rewiring a 1930,s house in 2 weeks time ,the upstairs dividing walls in the bedrooms are lathe and plaster .I am going to be pulling the upstairs lighting feed to all the points and dropping the switch drops before chasing as going to leave the house running as its ocupied.I have not come against lathe and plaster walls before i can sort back boxes out using dry line back boxes but not sure if i can cut out back box and pull the cable from the loft through the middle of the lathe and plaster with draw rod and in to the dry line back box how do you do it ??

Richard

 

[telectrix]

same as in any cavity wall for your drops. suggest cutting out for boxes with fein multitool. if possible, i would use existing positions and use old cable as draw wire. set up a few plug in lights to tide them over.

 

[londonlec]

Im currently doing one of a similar age/description.

I managed to use the existing conduits to pull the switch lines in.

In places there wasnt conduit I fished the cable down the wall with trunking lid, there was the odd noggin to get around though

I used metal backboxes and fixed pieces of wood behind lathe and plaster to get a decent fixing.

 

[londonlec]

same as in any cavity wall for your drops. suggest cutting out for boxes with fein multitool. if possible, i would use existing positions and use old cable as draw wire. set up a few plug in lights to tide them over.

Yeh I used a jigsaw to cut out boxes, make sure you buy a pack of blades though! The plaster kills them.

 

[tuckermot]

Hi tel

I would use old switch drop cable to pull through new cable from above in the loft but these are new switch drops going in .I take it there is no sort of nogging between the lathe and plaster so going to try and pull through with a draw rod/wire do you think this will work ?

 

[Richard]

There can be noggins, normally at a diagonal which can trick you if you end up having to notch the plaster to get round it! I have successfully drilled from above with a meter bit before now. If you have/can get your hands on a fein multimaster, it might make your life slightly less painful.

Rich

 

[telectrix]

generally you won't have trouble with noggins if you fit switches at a sensible height ( i.e. where we've always put then before the bureaucrats decided they should be sited for dwarfs).

 

[tuckermot]

whats best to use Metal or dry line back boxs in lathe and plaster

 

[Silly Sausage]

where we've always put then before the bureaucrats decided they should be sited for dwarfs).

Behave yourself, we all know that's new builds.

 

[sjm]

Lathe and plaster can be a nightmare. What I've done in the past is use surface mount pattress, if possible, or cut out a section of lathe and plaster between uprights (using fein multitool) replace section with plasterboard, including noggins etc, cut plasterboard for dryline box job done. Making good is required but the finished job wil, IMHO, last longer than just cutting out the lathe and plaster, which will reduce the structural integrity of the wall.

 

[GLENNSPARK]

trick is with lath n plaster walls is to let the fein do its job....nice n steady when cutting out for boxes....go oversize for the box...but not oversize for the lip at the front edge of the box.....this gives you an allowance as lath n plaster walls/ceilings dont like disturbance......

 

[J&M Electrical]

You'l also probably find about a ft of plaster inside the wall at floor level aswell which can be a pain if your trying to keep damage to a minimum. If your lucky you may well beable to fish straight up the walls. A couple we have done have had no noggins at all. 1 other bonus is that there isnt usually a noggin across the top so you can fish straight into the loft

 

[tuckermot]

thank you all for the good advice using a surface mounted back box sounds a easyer and less distructive way to fit the light switch with only having to put a small hole in the lathe n plaster to fish the cable through into the back box

 

[GLENNSPARK]

thank you all for the good advice using a surface mounted back box sounds a easyer and less distructive way to fit the light switch with only having to put a small hole in the lathe n plaster to fish the cable through into the back box

your perfectly ok to sink a dry box into lath n plaster as dont forget...once the front goes on and is tightened up.....it all gets a lot more supported...and thus stablises......

 

[Richard Burns]

Go gently with plaster and lath walls they are not very strong if they have been bashed a bit. I dropped out about a foot square on one wall and I was cutting with a stanley knife!

 

[needasparks]

How big was Stanley's knife then Richard ?

1930's places can be a pain as everyone always changes the way the doors open so no draw wire to use for the switches.

 

[Silly Sausage]

As a complete aside to the thread...
if you can get to the back/inside of a L&P wall, saturate it in 1 to 10 PVA, they firm up beautifully.

 

[Jel]

Lathe and plaster can be a nightmare. What I've done in the past is use surface mount pattress, if possible, or cut out a section of lathe and plaster between uprights (using fein multitool) replace section with plasterboard, including noggins etc, cut plasterboard for dryline box job done. Making good is required but the finished job wil, IMHO, last longer than just cutting out the lathe and plaster, which will reduce the structural integrity of the wall.

Got to Love the Fein multi tool. Has become a essential part of my tool kit!

 

[pjcomp]

Drylining boxes don't usually work with L&P - you'll probably find the plaster is too crumbly to provide a good base for the box. Best is to find an upright, chop it out a bit and countersink a metal box (unless the plaster is deep enough, which can be the case). Be prepared for patching up round the edges because that plaster can crumble away, especially once you start cutting through the lathes.

PJ

 

[GLENNSPARK]

Drylining boxes don't usually work with L&P - you'll probably find the plaster is too crumbly to provide a good base for the box. Best is to find an upright, chop it out a bit and countersink a metal box (unless the plaster is deep enough, which can be the case). Be prepared for patching up round the edges because that plaster can crumble away, especially once you start cutting through the lathes.

PJ

they do work with em....caus i have fitted em umpteen times......just got to go a bit careful...thats all.......

 

[Dave 85]

I just get me lump hammer and chisel and smash the arse out of the wall till I get an easy rout....
they don't call us house bashers for nothing

 

[telectrix]

rough sod. you qualify as a plumber.