Dealing with electric cables when boarding a loft.

[jrussuk]

Hi,
I'm going to partially board my loft of my 1900 terrace and wondered what is the best way to deal with the lighting electric cables which are lying on top of the rafters and insulation. The area I'm boarding is about 3m x 5m.
Many thanks

 

[stem]

Roof rafters are generally not as substantial as floor rafters as they are not designed to carry loads. Therefore, they shouldn't be notched or drilled to prevent them being weakened, so I would suggest that cables either be rerouted so that they are clear of the partial boarding, or new, non structural timber put on top the rafters that can be notched or drilled. Consideration should be given to protecting the cables from damage by any nails or screws.

 

[JohnD]

notching is always poor, but drilling at the centre line of a joist is generally considered good practice. A 1900 terrace will have a cut roof and may have generously sized timbers (unless it has been overloaded by taking off the lightweight slates and replacing with heavy concrete tiles)

 

[Taylortwocities]

Also, do not enclose the cables in loft insulation. They can overheat if they run through that.
As above, lay battens on top of the rafters and cut out to allow the cables to pass through.

 

[jrussuk]

I was going to leave the cable above the insulation as it is now. Would 2x1 timber screwed to the joists ok?

 

[oldbutnotdead]

Yes, roofing batten or that cheap CLS that B & Q are flogging at the mo will be fine. Where the cables are running along the joists, clip them to the sides of your new bit of stick- where they're crossing, notch the new stick so they sit below it. For strict compliance with wiring regs (assuming your lighting isn't on an RCD), make sure that where the cables are buried they're at least 50mm below the top of your boards (the cheap CLS is deep enough for that trick. Just). And for your own convenience, well worth getting a magic marker and marking on top of the boards where the cables are.

 

[jrussuk]

Many thanks for the advice