How to fit electrical back box if there is no back?!?
Mar 10, 2011 24 Replies
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Steven Campbell
I was installing a twin socket in a brick wall and had cut / chiselled out the brick ready for the back box. As I was drilling the remainder of the brick to hold the back box, the brick fell into the cavity so I'm now left with a hole with no place to secure the back box!!
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suggestions?
Thanks
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T
Tabby
Either use sand & cement or filler to stick it in place, or else screw it sideways into the inner wall leaf.
NT
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chrisj.doran
Could you use a "dry lining" box intended for plasterboard?
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ARWadsworth
Is that an external wall?
However, I would try to get a piece of timber into the hole that is longer than the horizontal bit of the hole and screw it to the wall and then screw the backbox to the timber.
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TheOldFellow
18mm plywood. Drill two 20mm holes in it, put in a bit of string between the holes. Wiggle it into place in the cavity with one end behind each end of the back box cavity. While holding in position with the string, put spray-foam nozzle into holes and get a big blob of foam behind the wood and over to the outer wall leaf. Wait in this excruciatingly painful position for about 10 minutes while the spray-foam goes off. Tomorrow screw the back box onto the plywood.
Insulation, penance, and a good back-box in one.
R.
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Roger Mills
Looks like a nice clean hole. Stick it with Gripfill to the brick/block-work which surrounds it. It won't move once the Gripfill cures.
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The Medway Handyman
Piece of timber longer than the hole is wide, large screw in middle to give you something to hold.
Large blob of Gripfil on the ends that will contact wall.
Feed in diagonally, pull towards you & hold until Gripfil grabs enough. Leave to dry & remove screw.
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Steven Campbell
Guys as usual thanks very much for the varying suggestions I'll just answer the lot here if that's ok.. Yes its an external wall. Which an extension has been built on to. However the brick is only one skin thick here which I didn't know. It seems to have been the old back door that they have bricked up. The other side is plasterboard at 13 inches away so I think that might be just too much for expanding foam. A dry-lining box works by the lugs grabbing the plasterboard. Unfortunately there would be nothing for them to grab. I like the idea of just "grip filling" it in as the box is a tight fit anyway. Or the suggestion of a Piece of wood at the back with grip fill and screwing on to that.
Thanks again for the numerous suggestions.
J
jgharston
You're lucky. My sister-in-law was chiselling out a hole for a back box when the bricks fell out into the next-door room leaving a nice brick-shaped hole through the wall.
JGH
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Nick Leverton
All these herculeans are welcome to come round and dig us out some back boxes, I've done two rooms of this brick so far and not looking forwards to the rest !
Nick
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Triffid
My brother in law was chasing a cable run into his bathroom wall for an electric shower when an entire breeze block fell through into the bedroom next door. It fell onto the bed where a wrapped-up wedding present was lying (an expensive Dartington Crystal fruit bowl). Smashed it to pieces!
Still - good job there was no-one in bed...
-- Triff.
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robgraham
Don't you mean 'Amazons' ! Impressed that one of the fair sex is doing this sort of thing; there's no way I could get my wife to do that.
Rob
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jgharston
She does most of the chiselling, first-fix plastering, painting and decorating. My brother does most of the cable drawing, wet plumbing and final fix plastering. I do the wiring and testing.
JGH
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Tim Watts
jgharston ( snipped-for-privacy@arcade.demon.co.uk) wibbled on Friday 11 March 2011 13:40:
we are not worthy!
J
John Rumm
Yup, if he could bottle that, he would be rich!
J
John Rumm
A decent SDS drill makes it child's play... I can do a double socket cutout in brick in 10 mins these days.
J
John Rumm
My cousin Dave was revamping his kitchen once, and found a large lump of Bath stone set into the wall that was in the way of a cabinet he wanted to install. Having deduced it was not actually fixed in place he set about wiggling it from side to side and pulling it out of the wall. With a final huge heave it suddenly came free and he realised it was far deeper than he had though. He also got a nice view of his neighbour sat in his kitchen at the breakfast table smoking his pipe. The neighbour sat there calm as a cucumber (having just watched a bit of his kitchen wall slowly retreat all by itself), said to him in his rich west country accent:
"Morning David, know what you are doing do you?".
Dave's answer being:
"Yup, I will be round to re-plaster your wall later!".
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Steve Walker
I've done that - a couple of days after decorating the other room :(
The funny one though was when we had cavity wall insulation put in. The whole house is cavity wall, except for one small section - they totally filled the electricity cupboard! Luckily it was a blown fibre and could easily be removed.
SteveW
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Nick Leverton
Bit more of an amateur here with a Screwfix special SDS, plus our bricks hereabouts have extra hard but brittle inclusions in (I warned the electrician who rewired previous property to bring his extra-hard chasing tool and he didn't believe me !).
Nick
M
Mathew Newton
You need to get yourself an SDS drill with chisel bit. It really is the proverbial 'hot knife through butter' for this task...
Mathew
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