So you're faced with a re-wire and the ground floor is a concrete one...

[Mr.Si]

...what would you do?

I am faced with this for my own place and as the time gets closer to when I will be carrying this out, I am fishing for ideas.


My initial thoughts were to channel out the floor and chase up the walls to the socket points, lay steel conduit in it and wire in singles. Once done, I'd then fill the floor (except I don't know what you'd fill the gaps with, so there lies another question!).

However, would there equally be value in taking the cables via the ceiling instead of the floor (Twin and CPC) and just chasing all the way down the wall to the socket points instead?

I don't want surface mount.

What would your choice be?

Downstairs there's a kitchen and a lounge and a cupboard under the stairs, which is accessed via the lounge.

Your thoughts, ideas, experience and advice would be much appreciated.

Thank you in advance.

Si

 

[rocker]

Just do everything under the first floor and channel down the walls, surely. Am I missing something here? Channelling out a concrete floor would be madness!

 

[bugsy]

From the first floor down

 

[telectrix]

agree with both^^. why make hard work when chasing plaster is easy. and more conventional.

 

[RWJ]

Again as per previous posts....... Chase out walls unless you really like the challenge!

 

[telectrix]

and if you want it rewireable, use oval tube, not capping.

 

[elektrisien]

What is the difference between oval tubing and capping ? excuse my ignorance.

 

[PC Electrics]

'from above' seems to get the popular vote! gets mine too.

 

[telectrix]

capping is what it says. capping over the cable. oval tube is conduit thats flattish so as to fit plaster depth without cutting into the brick, as you would have to do with round conduit. and you can fish new cables in tube. with capping it's not that easy esp. if the wall is uneven.

 

[rocker]

The difference is oval is good and capping is tosh.

 

[Electricalserv]

Just do everything under the first floor and channel down the walls, surely. Am I missing something here? Channelling out a concrete floor would be madness!

What about the new builds with concrete gound floors and first floors....going to be an absolute headache in the future.....

Obviously from above...no brainer really

 

[brucelee]

Hi mate there are a lot of existing flats which have concrete floors for both flats so they are done in trunking around the top of the wall and then chased into walls from ceiling to switch or socket
if the ceiling is not concrete then deffo above if its is still above but with trunking forget channelling the concrete floor

 

[RWJ]

Coving Trunking.... MK do it

 

[Mr.Si]

Thank you all for that.
As you probably understand, I'm still fairly new to it all and so was intrigued as the best options. The first floor is joists, so I'll route the cabling through them.

Has anyone ever had no choice but to actually channel the concrete floor before? if so, how did you do it? angle grinder?

 

[Electricalserv]

Thank you all for that.
As you probably understand, I'm still fairly new to it all and so was intrigued as the best options. The first floor is joists, so I'll route the cabling through them.

Has anyone ever had no choice but to actually channel the concrete floor before? if so, how did you do it? angle grinder?

I was in the wholesalers and a guy came in saying he was channeling floor out. He was using a breaker, said it was a nightmare.

 

[Geordie Spark]

Thank you all for that.
As you probably understand, I'm still fairly new to it all and so was intrigued as the best options. The first floor is joists, so I'll route the cabling through them.

Has anyone ever had no choice but to actually channel the concrete floor before? if so, how did you do it? angle grinder?

The only time I've had to channel the floor is to run gas pipes & I used a Sthil saw - with water to keep it cool & the dust down.

I'm doing a rewire at my girlfriends house just now & because it's a concrete floor I'm bringing everything down from the upstairs.

 

[slpotts]

scary to think that someone who needs to ask such a ridiculous question is actually considering a career in the electrical industry.

 

[Knobhead]

Just to put you off chasing the floor even more, remember there’s a damp proof membrane under there.

 

[Paul.M]

scary to think that someone who needs to ask such a ridiculous question is actually considering a career in the electrical industry.

I think he is just trying to confirm his own ideas. Besides its his own place and may be using this to gain experience, his question is not about electrics, just how to route the cables, he may not have come across this problem before therefore not a ridiculous question.

Sorry slpotts if that sounded harsh . If this was on site you'll have me chase out the floor with a 1 inch chisel whilst you use the hilti .

 

[malcolmsanford]

Normal domestic situation of having the ground floor in screed is to work from above down the walls by far the easiest way to do it.

The only other alternative really if you want is the use of MICC, quite a lot of flats that were built in the 60's that were of block and screed were run in MICC, just a small channel cut out of the block and screeded over. It would be quite easy for ring finals or radial on the sockets which is what you need. Lighting was al ittle harder and I remember that the ends were just potted into not very nice bulkhead type fittings, so you would need to think about the lighting a bit more.

Of course then there is cost, not the cheapest of material to work with, but it is as they say an alternative point.

 

[Mr.Si]

Malcolm, that's an interesting idea! As you say - expensive but it would be a great practising ground for working with MI cable.

However, I think I'm definitely going the top down route.

Paul, thanks for that, you are right - it's because I've never come across the situation before and am considering the options available. Hence the question, so thanks for backing me up.

SLPotts, if I have a query regarding electrical issues, I'd first consult my big red book / OSG or notes, so don't you worry.

 

[rocker]

Personally I think that anyone who wouldn't ask a question for fear of losing face are trhe ones who need to be out of the industry.

Like it or not, the kids today are all theory and no practice, and they need to ask for help in places like this. To us it seems like a total no brainer but what if you'd never done it before? You can't ask your gaffer because he's a prat in an office and hasn't got a clue. You know that usually the S/Os come from under the floor so why not ask if there's an easy way to channel out the concrete?

I've been in this game for a little while now, and I still ask stupid questions on here on a daily basis. Vive la stupid questions.... they make stupid mistakes avoidable.

 

[brucelee]

Hi mate
better to look a fool for asking than a bigger fool for not asking we all live and learn someone shows me how to do it today then i will show someone how to do it another day
its how everyone learns

 

[slpotts]

I think he is just trying to confirm his own ideas. Besides its his own place and may be using this to gain experience, his question is not about electrics, just how to route the cables, he may not have come across this problem before therefore not a ridiculous question.

Sorry slpotts if that sounded harsh . If this was on site you'll have me chase out the floor with a 1 inch chisel whilst you use the hilti .

Get sharpening your chisels paul....

 

[pushrod]

.

Like it or not, the kids today are all theory and no practice, and they need to ask for help in places like this. .

... and it's not just the kids

 

[Paul.M]

Get sharpening your chisels paul....

I know you will get your own back on site . Guess I'll be doing all the dirty work next time .

 

[Phil]

once did a pub with concrete ceilings and floors 'nightmare'

 

[phil_davison]

once did a pub with concrete ceilings and floors 'nightmare'

Thats what I'm doing at the moment. Been a nighmare but 3 days of chasing floors and walls the dirty work is finished. Well hopefully.

 

[richy3333]

The only stupid question is the one never asked

 

[mogga]

Scottish special housing association houses mid 60s>70s were poured on site concrete (Nofine) a barsteward to get a fixing the electrical system came prebuilt similar to kpoex and like a big spider sprawled on the floor before the screed went down Pain in the but when there was a fault
I much prefer the commercial somution Raised Floor Systems | Access Floors | Computer Floors | Suspended Floors | Comms Room Floors | Air Grills lol

 

[Electricalserv]

Scottish special housing association houses mid 60s>70s were poured on site concrete (Nofine) a barsteward to get a fixing the electrical system came prebuilt similar to kpoex and like a big spider sprawled on the floor before the screed went down Pain in the but when there was a fault
I much prefer the commercial somution Raised Floor Systems | Access Floors | Computer Floors | Suspended Floors | Comms Room Floors | Air Grills lol

Thtas the best way in my opinion . If the customer can comprimise and have ceilings and floors raised. If the rooms have enough height that is!

 

[rocker]

Scottish special housing association houses mid 60s>70s were poured on site concrete (Nofine) a barsteward to get a fixing the electrical system came prebuilt similar to kpoex and like a big spider sprawled on the floor before the screed went down Pain in the but when there was a fault
I much prefer the commercial somution Raised Floor Systems | Access Floors | Computer Floors | Suspended Floors | Comms Room Floors | Air Grills lol

All the old housing association places round here are nofine, bloody awful stuff! I just don't chase the stuff out now if I know it's there, there's a school of thought that reckons chasing it out will severely weaken the structure oif the building. Actually I reckon you were the first person who told me what it was, Mogga. I was like 'Jesus, there's a house made of loose shingle!'. Such weird stuff.

 

[Benny_Boy]

All the old housing association places round here are nofine, bloody awful stuff! I just don't chase the stuff out now if I know it's there, there's a school of thought that reckons chasing it out will severely weaken the structure oif the building. Actually I reckon you were the first person who told me what it was, Mogga. I was like 'Jesus, there's a house made of loose shingle!'. Such weird stuff.

Rewired quite a few of those bad boys. I find fixing backboxes is best accomplished with a bonding/cement mix. Mix it up and you've got about 20 seconds before it's gone off, box is fixed and not a rawl plug in sight.

 

[mogga]

thats the stcker its poured then boarded out dot n dad style absolute crud to fix to and forget drilling n plugging The Bonding/Cement mix sounds better than the Expanding foam Iv seen used