loft panels - which way up (and does it make much difference

[dandt]

sorry to be thick [and I have searched for this honest]
I have some panels from B and Q
Everything is going fine so far except for the fact the instructions dont show the profile clearly enough. I was thinking of laying them so that the receiving panel contains the lowest third jutting out and flush with joist, however the ink on the boards is then face up (and maybe this should be a clue that the ink goes down). However ink down feels like they would be harder to lock in together. I dont know if there is a standard profile (ie if I buy more from say homebase would they be compatible)
Anyway for any replies

 

[PrenticeBoyofDerry]

You'll find they lock in better ink side up, it is also best to start boarding out from your loft hatch opening and also remember to leave some ventilation at the eaves.

 

[dandt]

I can now crack on (I didnt want someone to say afterwards..haha youve laid them all upside down). Im keeping the eaves well clear as you suggest
thanks

 

[PrenticeBoyofDerry]

Yep crack on, screw the boards down, don't nail.
This will give you ease of access if ever needed at a later date.
Beware of any pipework or electrical cables, you don't want to be damaging them with the screws.
It will also be a good idea to leave traps, for any electrical junction boxes that are in the ceiling void or alternative fit the junction boxes above the the loft floor.
I say this because current electrical requirements state that cable joints, such as junction boxes, should be easily accessible for inspection and testing.

 

[dandt]

thanks
my genera diy is better than my original question may suggest
Ive got new 'joists' for extra support at right angles to original at the perfect intervals for boards and so cables no problem (ive also taken heed of many posts about dangers of insulating cables (even if lighting) so mine are housed in 32mm/40mm waste piping so they are ventilated from insulation material
thanks again

 

[PrenticeBoyofDerry]

Having power cables routed through waste pipes will I suspect be the same as installing the cables in conduit.
Which there is a de-rating calculation to be considered, regarding the current capacity of the cable.
The safety of the cable will need to be assessed and some calculations made, regarding the protective device, cable size and installation method.
Generally if it is a lighting circuit protected by a 6A MCB or a 5A fuse, the cable will be sufcient if 1.00mm2 plus.
It will be power circuits such as sockets, showers and cookers that are more than likely not to comply, as the the cable size/current capacity of the cable is designed much closer to the fuse rating, so it those that would cause me concern.is