1930's flat rewire - Concrete floors & ceiling

[deadshort]

Yes it's Friday …..pub time

DS

 

[sparkwright]

Hi,

I just had an electrician tell me there would be no problem grinding a small channel for single drop lights in each room. This would be on condition I removed the artex surrounding the run. He said it would be so shallow it wouldn't impact structurally and he's done it before on many flats like mine.

Does this sound right? Bearing in mind the ceiling is concrete above what seems like quite a thin layer of atrex/plaster?

For goodness sake, how often do have to say it? A false suspended ceiling is the way to go - you can forget about that old ceiling once you have a false ceiling below it, plus bags of space to run cables. No mess. No bollloxing about putting cables behind coving. You can have recessed spots too if you like.

Anyway, I'm not going to go on about it any more...

(EDIT; just seen he really, really doesn't want a false ceiling because of cost and space.)

 

[stillp]

It doesn't sound a good idea to grind a channel in the ceiling - isn't that like notching the underside of a joist?

 

[securespark]

Are there any zones in a solid ceiling?

 

[JohnW2]

Are there any zones in a solid ceiling?

BS7671 says nothing explicit about routing cables in ceilings nor, AFAIAA about any considerations regarding protection of cables 'buried in/above ceilings' - it only mentions such explicit things in relation to walls. For cables below floors or 'above ceilings' there is only a vague statement (522.6.201) that they "...shall be run in such a position that it is not liable to being damaged..."

Kind Regards, John

 

[Adam_151]

Are there any zones in a solid ceiling?

No, You'd want your cabling to be either 50mm from the finished surface or in earthed metallic protection. This thin channel with 'presumably' twin and skin in it is at risk of being drawing pinned... even more on a concrete ceiling "Hey, this line here is soft enough to get the pin in for some reason!"

So that'll be MICC required then...... best go back to the drop the ceiling 50mm plan instead

 

[securespark]

I think you could reasonably interpret "below floors" and "above ceilings" to describe a cable recessed into a solid ceiling.

 

[EFLImpudence]

Are there any zones in a solid ceiling?

All chases must be horizontal.

 

[JohnW2]

I think you could reasonably interpret "below floors" and "above ceilings" to describe a cable recessed into a solid ceiling.

Yes, indeed - but, as I said, all BS7671 has to say about that is a vague staement about "not liable to be damaged" - no regulations/requirements about 'zones' (which is what you asked about), protection of shallow-buried cables etc. etc. in the same way that there are for walls.

Kind Regards, John

 

[EFLImpudence]

I agree with Stillp. I would not do it.

 

[OwainDIYer]

half-inch thick battens can be shot nailed into the concrete, this will have minimal effect on the asbestos-containing artex and with plasterboard will be less than an inch in total thickness.

 

[flameport]

It doesn't sound a good idea to grind a channel in the ceiling - isn't that like notching the underside of a joist?

It can be. Even if not, it will be highly unpleasant messy work for someone.

Other considerations are that in many blocks of flats, cutting into ceilings or the floor is not permitted anyway, as that isn't considered to be part of the flat.

There is also the issue of how the asbestos laden artex is to be removed so that this channel can be cut in, and what is being done to the ceiling afterwards.

 

[Crabbe]

Hi again!

Sorry the main reason I was trying to avoid boarding over, is it basically doubles the cost in every quote I've had. In the region of 2k extra. I'm not looking to have spotlights or anything fancy, so it just seems a lot for the sake of 4 drop lights in 4 rooms and I'm on a tight budget.

Had another guy come today and he claims you must have the cables in a metal casing, so if I took the other guys advice, it wouldn't be up to regs. He said the cable would get eaten away over time, but that doesn't seem right to me. Seems every person I get a quote off, has a different story!

Anyway, I totally understand that boarding should be the way to go... just need to find a couple of grand laying around

Thanks again.

 

[JohnW2]

Other considerations are that in many blocks of flats, cutting into ceilings or the floor is not permitted anyway, as that isn't considered to be part of the flat.

I can believe that. What about nailing/screwing into them to attach a suspended ceiling - is that likely to be permitted? (I suppose one could use adhesive!).

Kind Regards, John

 

[sparkwright]

Hi again!

Sorry the main reason I was trying to avoid boarding over, is it basically doubles the cost in every quote I've had. In the region of 2k extra. I'm not looking to have spotlights or anything fancy, so it just seems a lot for the sake of 4 drop lights in 4 rooms and I'm on a tight budget.

Had another guy come today and he claims you must have the cables in a metal casing, so if I took the other guys advice, it wouldn't be up to regs. He said the cable would get eaten away over time, but that doesn't seem right to me. Seems every person I get a quote off, has a different story!

Anyway, I totally understand that boarding should be the way to go... just need to find a couple of grand laying around

Thanks again.

But surely it's not just four drop lights, is it?

Don't you need to rewire the sockets and cooker, etc?

How are you going to do those if the floor is concrete?

CAN THE EXISTING LIGHTING CONDUITS BE RE-USED OR NOT?

If new wires can be drawn in, then you don't have a problem with the lights.

But what's the socket wiring like? There won't be many conduits for these.

Will you be using coving for any socket wiring then, like you mentioned?

SEE IF THE LIGHTING CONDUITS ARE RE-USABLE. In theory they should be, if the floors and ceilings are solid concrete, I see no good reason for them to have installed anything else than 'proper' conduit.