Is drilling rafters OK?

[Des 56]

The op asked his question, got the answers he did not want
He may now have returned to the land of arrogance with no response given and never to be heard from again
I wonder whether the same arrogance will continue on that job unabated, despite what has been advised

 

[7029 dave]

Cables don't just appear by magic, he has done nothing wrong.If you do not what concealed wiring, there is always the surface option.

 

[7029 dave]

The op asked his question, got the answers he did not want
He may now have returned to the land of arrogance with no response given and never to be heard from again
I wonder whether the same arrogance will continue on that job unabated, despite what has been advised

But they all know best.!?

 

[electric will]

what the hell?

 

[electric will]

Everyone in this thread, knows that the building regulations do not allow the drilling of rafters

 

[electric will]

Why Is everyone making such a big deal of it?
We all do the same, drill the bloody hole, feed your cable through it.
Then just make sure it's hid behind the insulation before the building inspector comes

 

[sparkypaul2]

Under Regulation L, you can drill through the middle of solid wood joists in the UK Read it as part of my current electrical course fairly recently, but in America you can't drill their composite (not solid) absolutely correct on the composites with an exception if you can get an engineer to approve a location that he deems is safe(usually within 6 inches(15cm) from the vertical support. It's covered in building code and not electrical here. Generally drilling has to be 1/3 or less of width of the beam /wood being drilled and done in the center of the piece being drilled. that is a 2x6 could have a 2 inch max hole drill dead center. More of a concern for plumbers than sparkys here. Notching is allowed with protective metal plates for the wiring but I prefer holes over notching as it is logic that in the place of the notch you are creating a different size of beam if you notch deeply and a source of weakness in support.

 

[telectrix]

I'd be wary of drilling holes in the rafters of flimsy modern roof trusses, but the OP's rafters were built before the pencil-neck accountants stuck their oars in to "design" structures that would just about stand up to their load bearing capabilities until someone farted.

 

[Volt]

The idea in the regs about drilling the centre of a beam/rafter (rafter is an inclined beam!) is that it is the neutral axis in bending - there is very little stress within the neutral axis fibres. However shear stress is more important at the ends near the areas of bearing as it is maximum at these points and so drilling/notching should be avoided here. As those rafters are only taking the roof weight and snow loading considerations it is unlikely for those sizes to be a problem in shear in your situation.

However, I would have taken the cable through the thick fillet section on top of the beam. It appears deep enough to miss battern nails.

 

[D00DY_T00DY]

and get some hairy-arsed roofer nail them.

I think you'll find my dad's a roofer.

And I can ensure you that he only glues tiles on with silicone