Opening up roof and sarking for wiring: common practice?

We're in need of installing some additional wiring and the only way to do that is to go through a roof cavity space that has no manhole access.

The electrician recommended to remove some roof tiles, make an L-shape cut in the sarking to gain access, then patch it up again.

I expressed my concerns about that approach, but he is very confident that it's common practice and it's guaranteed not to compromise the effectiveness of the sarking.

This electrician is highly recommended and I've used him before, however never for any work like this.

Can someone comment if this is indeed common practice and 'guaranteed' to be effective if done correctly?

Thanks!

I reckon that if you're right that the wiring needs to go in places where there is no access via a manhole, then yes, he has to get in the way he has suggested. Gotta get in there somehow, right?

I had the lights and fans rewired at one of my places a couple years ago and like you he needed to go places in the roof space that had no access other than to lift tiles etc. We have never had an issue.

If there is no access, how else would he get in??

Seems easier than cutting a hole in the ceiling

Going through the roof is pretty common.

For running cables down outside walls it's often the only way it can be done as there isn't enough height to get to the top of the wall even when there is roof space access.

I always look to provide roof space access with the garage being the best place to locate the manhole.

How come there is no access manhole for roof space?