DIFFICULT JOB !!

[mikep]

Anyone had a similar problem like this, got a very small new build bungalow to wire, problem being concreted floor, walls are going to be plasterboard dot & dabbed off of the blockwork, roof structure vaulted ceilings made up of 150mm rafters with 75mm celotex in between plus 50mm celotex underside of them, now the rafters could be under battened then celotex to create cable void then plasterboard on battens and i can run cables through this void then drop down walls to light switches & down walls to sockets.

Could just run the ring behind the plaster board at 450mm from floor level then through into next room

they also want downlighters cut through the celotex into ceiling between rafters but i think it will be a problem trying to keep the u value plus the fire risk to insulation etc.

Anyone got any experience with this setup.

Might just ask building control how they want it.

MIKE.

 

[Andy™]

NO NEED TO SHOUT

nothing wrong with cable around room between sockets, providing its in a zone. if not, add a socket to make it

you can fit downlights with kingspan, best to make a 6" hole. but inspector may ask for insulation to cover the top of the hole you made for downlights

 

[ElectekAir]

Also make sure any JB's you use will be able to be pulled through the downlight holes as after you will not be able to get to them

 

[mikep]

Cheers Andy for the reply.

Yep taken the cap lock off, thought it would be quicker to type it like that, I would like to do drops as I can get the cable round easier just what to do with the rafter situation with the insulation, as I said wonder if building control would advise.

Mike

 

[sparkytim]

Why not just clip cables to rafters above insulation level i.e. close to felt.

 

[mikep]

Bathroom is between lounge and bedroom, with standard ceiling so nice central point to go out from just under the ridge then down under the rafters on top of the battened off plasterboard.

 

[mikep]

Hi Tim,

I suggested that as it is above the Celotex in free air but below the tiles with a nice space of 75mm dropping through the celotex to the lights and sockets. Less of a fire risk.

I wonder what building control would say ??

 

[Graham Lister]

Dont see a problem clip to rafters drop down walls where you need. Downlights just cut back suitable amount of celotex as has been said.

 

[JUD]

Why not just clip cables to rafters above insulation level i.e. close to felt.

I did this on my brother's new build bungalow and BCO wasn't happy. He said they had to be 50mm down from felt and 50mm up from ceiling.

X(X( X(

I know they have to be 50mm up from ceiling and down from floorboards, but never seen anything in the regs about the roof.

 

[a1]

I did this on my brother's new build bungalow and BCO wasn't happy. He said they had to be 50mm down from felt and 50mm up from ceiling.X(X( X(

Couldn't find anything in the regs but he made me move them all down.

They do - Problem is, on most houses the roof rafters / trusses are only 3 by 2.

 

[JUD]

They do - Problem is, on most houses the roof rafters / trusses are only 3 by 2.

I was lucky. He had used 200mm rafters so just moved them down into the middle and kingspan had to go over them.

Is there something in the regs about distance from roof felt etc?

I've seen regs about floorboards and ceilings but can't find anything about roof.

 

[a1]

I was lucky. He had used 200mm rafters so just moved them down into the middle. Is there something in the regs about distance from roof felt etc?

I've seen regs about floorboards and ceilings but can't find anything about roof.

I am almost certain that someone previously mentioned that it was in tone of the building regs.

But BC will probably say "If in doubt, use the same reg as the ceilings and floorboards)"?

 

[Graham Lister]

Get the ceiling boarded before BCO comes out!

With one side of the cable touching the rafters I think it should still be ok for 2.5mm ring and 1.5mm lights even if the kingspan covers the other side of the cable. Could be wrong but cant see a justification for 4mm in this situation.

As for the 50mm away from roof who is going to be banging nails through roof tiles? I thought the 50mm rule was more for holes through joists not where to clip cables?

In this real world situation where the roof trusses cannot be drilled then comprimises have to be made.

 

[JUD]

As for the 50mm away from roof who is going to be banging nails through roof tiles?

My thoughts exactly, but he still wanted them moving down. headbang

 

[sparkytim]

Only mention of Roof rafters in Building Regs Part A is NOT to cut notches OR drill holes.

50mm not mentioned, just holes to be made ctr line of floor joists, between 0.4 and 0.25 of span out from ends.

Sounds like he was making up his own version, but what can you do?

 

[M107]

Could you not use the 50mm safe zone between wall & ceiling to run the cables, before dropping to switches/sockets? I know the ceiling is vaulted but it's still a ceiling.

 

[mikep]

Thanks all, I have now run ring etc with drops from the safe zone, this is a right pig of a job, all that cable up round the top in the safe zone is still risky but the only option for this build,.

Woman client wants downlights fitted in the ceilings so have asked building control they said only low energy fire rated to be used due to heat, going to use the dimmable fire rated low energy mains units in the shower which are suitable.

the next problem is to run all the cables through the lounge to the kitchen, looks like the safe zone and plastered over, I hate this job cos I don't think the safe zone is safe!!

Mike.

 

[JUD]

Thanks all, I have now run ring etc with drops from the safe zone, this is a right pig of a job, all that cable up round the top in the safe zone is still risky but the only option for this build,.Woman client wants downlights fitted in the ceilings so have asked building control they said only low energy fire rated to be used due to heat, going to use the dimmable fire rated low energy mains units in the shower which are suitable.

the next problem is to run all the cables through the lounge to the kitchen, looks like the safe zone and plastered over, I hate this job cos I don't think the safe zone is safe!!

Mike.

Seems like you've got a similar job to my brother's. I also had to run cables in the safe zone (diagonal in line with vaulted ceiling).

At the end of the day a safe zone is only safe if the person drilling the wall knows where they are :C :C