2 Bed Ground floor maisonette

[Amar]

Hi folks,

I have been asked to rewire a couples ground floor 2 bed maisonette, purely because they want a load of extra sockets, new 10mm shower supply, mains smokes/heat, new kitchen layout and spot lights etc. Which is fine but all the ceilings and floor and walls are concrete.

My idea was the baton the ceilings with 3x2, fixed with a Hilti gun/plug and screw, allowing a void for new cables and spots.

Can I chop and chase the concrete walls for new/extra socket outlets without weakening the structure of the building??

Surely its the same principal as a conventional brick and mortar building as in chasing the bonding/plaster back to concrete hoping its deep enough or to be able to chase out the minimum amount or brick/concrete required to fit sheathing/boxes just bellowing plaster level??

Anyone had any experience with this?
Thanks

 

[Pete999]

It's not the same principle at all, not all brick walls are load bearing walls, non load bearing walls can be chased, I'm not sure of the rules governing load bearing structures, someone else with more experience will be able to help, how is the dwelling wired now? conduit, MICC?

 

[Amar]

Currently in conduit but they just have 1 single socket in bedrooms and 2 in the living room

 

[Pete999]

Currently in conduit but they just have 1 single socket in bedrooms and 2 in the living room

I realise surface trunking is not ideal but could you not limit any chasing by utilizing the conduit and extending the wiring to the sockets at skirting level in trunking? done properly using the right accessories it can be made to look a decent install, or are you determined to carry on with the flush method? Good luck anyway.

 

[KEV 1 N]

I worked in some flats with concrete walls years ago, we weren't allowed to chase the walls at all, even core drilled holes had to drilled in certain places and kept to a minimum diameter. The idea of using the old pipes, then run the cables in a skirting trunking is a good one. What about dot and dabbing the walls?

 

[KEV 1 N]

Plus concrete gets harder as it gets older, wouldn't fancy chasing it plaster depth, never mind 25mm for a socket box!

 

[Amar]

haha Yeah! I was just thinking how much of pain it would be chopping boxes out.
The problem with utilising the existing conduit drops are, the lack of them, I don't think they would be too happy having trunking everywhere neither.

Would it be ok to baton the ceiling out using a Hilti gun ??

I did mention hacking off all the existing plaster back to the concrete, then dot and dab onto that, as battening onto the existing walls is going to cause a problem with door frames.

Just wanted to see if anyone else had tackled it and come up with any other suggestions

 

[Pete999]

haha Yeah! I was just thinking how much of pain it would be chopping boxes out.
The problem with utilising the existing conduit drops are, the lack of them, I don't think they would be too happy having trunking everywhere neither.

Would it be ok to baton the ceiling out using a Hilti gun ??

I did mention hacking off all the existing plaster back to the concrete, then dot and dab onto that, as battening onto the existing walls is going to cause a problem with door frames.

Just wanted to see if anyone else had tackled it and come up with any other suggestions

Don't know but mind you don't shot anyone living on the next floor, now that would be interesting, I take it from your question you will be doing the ceiling yourself, do you have any building / construction experience or qualifications, or are you just hoping for the best?.

 

[KEV 1 N]

Yeah hilti gun should be fine, or drill and hammer in fixings.
You might struggle to pull cables through the old conduit for the sockets anyway, and if it snaps off half way through a pull, your knackered! Could you get away with dot and dabbing say 2 walls in a room to put the sockets? Example, leave the window wall alone and do the walls on each side

 

[Amar]

Don't know but mind you don't shot anyone living on the next floor, now that would be interesting, I take it from your question you will be doing the ceiling yourself, do you have any building / construction experience or qualifications, or are you just hoping for the best?.

Yeah I have experience in construction/building. Brothers a carpenter and we have plasterers that work for us. We refurbish properties alongside out electrical work but not really worked on this type of property before so just wanted to pick some brains.

 

[Amar]

Yeah hilti gun should be fine, or drill and hammer in fixings.
You might struggle to pull cables through the old conduit for the sockets anyway, and if it snaps off half way through a pull, your knackered! Could you get away with dot and dabbing say 2 walls in a room to put the sockets? Example, leave the window wall alone and do the walls on each side

Yeah no way would we be able to pull through the existing conduit. When they built these houses in the first place I'm guessing they pulled through the singles at various point. Me trying to pull them from the board to outlets would just snag the cables to bits. Would cause more problems then its worth which is why we would drop the ceilings

You must be able to chop the walls a little as the existing switches and sockets are chopped in?

 

[The Ghost]

It depends when the houses were built and what type of concrete construction was used. A lot of these houses are now considered structurally defective. I imagine chasing will further the defective nature of them. Personally without an architects or structural engineers say so I would not consider doing such a job due to the danger of furthering structural defects. I would look into it before committing yourself to unlimited liablity. I would suggest such to the client and offer some surface options. I do not think I would even use a Hilti on them before getting someone else to take the liability by issuing a statement it is safe to do so. And of course you may go through the conduit with a Hilti. Even if you got the all clear you need diamond cutting blades and SDS to cut out the chases which take a lot more time, so allow for that.

 

[KEV 1 N]

Yeah no way would we be able to pull through the existing conduit. When they built these houses in the first place I'm guessing they pulled through the singles at various point. Me trying to pull them from the board to outlets would just snag the cables to bits. Would cause more problems then its worth which is why we would drop the ceilings

You must be able to chop the walls a little as the existing switches and sockets are chopped in?

Wouldn't like to say really, are you sure the old conduits have been chased in or have the been "cast" into the concrete when it was first poured?