Boarding up the garage ceiling

[Vikash]

Hi,

I want to board the ceiling of my garage, insulate, add some more lighting and use the space above for storage. The garage was build about 7 years ago and has a trussed roof. The truss floor timber measures 70mm x 35mm, and is joined over the 5.4m span with metal connector plates. The garage is detached from the house but joins another set of garages (also detached from any houses).

I have been told the roof has a breathable membrane and there appears to be no ventilation holes in the eves.

So here are my questions
1. Do I need to use vapour barrier lined plasterboard, or will normal stuff be ok?
2. As the gap is only 70mm what should I use for insulation? Rockwool?
3. Boarding the top up for storage (B&Q floorboards probably) will it be safe to walk up there and store the usual garage rubbish?
4. Is adding extra lighting from an existing spur(s) notifiable in the garage?

V

 

[johnf]

I would be very careful how much weight you put up there

 

[pip1954]

i would say maybe not very small joists and plates are for joining trusses not for walking on.
pip

 

[Phil Pascoe]

As the above two comments - trusses are for carrying roofs not floors. Be careful how much you expect of them.