Cable routing - flat roof

[MichaelTT]

Hi All

Firstly, sorry for the long post but wanted to give some background.

A customer has asked for a newly built conservatory/extension to have power supplied: 4x sockets and a light. The original plans were for for the kitchen RFC to be spurred from to provide the required supply.The building has now been built, but unfortunately the customer has changed their mind on what they want to supply. They've asked for a new supply with 3x new circuits consisting of sockets, lighting, underfloor heating (10m2) and outside power/lighting.

The issue I have is that the house is very newly refurbished to a high standard and so the customer wants no disruption to the internal decor of the house. The CU is in the attached garage to the left of the property, spanning the entire length of the property, with a part pitched roof to the front and a flat roof to the rear.

They've asked if I can route conduit through the garage, up through the flat roof, up to the eves of the house, cable routed via the loft space then back down to the other side where the conservatory/extension has been built.

My question is, can we run cable directly through a flat roof from the garage to outside, without damaging the integrity of the roof and without making it look rough? I intend to run singles through 25mm conduit for the supplies.

Thanks all,

Mike

 

[mwatsonxx]

Never never never take cables through roofs, unless your client employs a roofing company to create the entry point and weatherproofing and take full responsibility..

 

[ban-all-sheds]

The issue I have is that the house is very newly refurbished to a high standard and so the customer wants no disruption to the internal decor of the house.

And I want to drive a Ferrari with Claudia Schiffer naked in the passenger seat, but you can't always get what you want.

If someone changes their mind about where they want buried services to be buried after they have finished off the surfaces of where they want them buried then they have to choose between magic or disruption.

Flat roofs are tricky to get right at the best of times - don't make holes in one. Is routing the cable outside underground an option?

 

[MichaelTT]

Thanks both

I could ask the question of whether outside is an option.

Failing that, can you conduit across the flat roof (so out of the side of the garage, up and over the flat roof, up the side of the house?)

This option just seems a bit naff, given that when the flat roof is replaced at some point, there will be conduit across it!

I tried to draw you a diagram but have failed...

 

[MichaelTT]

I think I'll opt to tell the customer that it's not viable without disruption to the house. Thanks for your responses.

 

[mwatsonxx]

Failing that, can you conduit across the flat roof

Yes, fix the conduit to paving slabs, that have been supplied and laid by your clients roofing contractor.

 

[ban-all-sheds]

Failing that, can you conduit across the flat roof (so out of the side of the garage, up and over the flat roof, up the side of the house?)

Electrically, yes, as long as you do it properly.

This option just seems a bit naff,

Doesn't it though.

given that when the flat roof is replaced at some point, there will be conduit across it!

The cable could be put into the roof at that time. Or a new cable could if the existing one were to be too small for the changed installation method.

I tried to draw you a diagram but have failed...

https://www.sketchup.com/download/all

 

[Lectrician]

Why can’t the conduit go on the wall of the house rather than roof?

Singles in conduit sounds a PITA to me.