Insulating a ceiling while still keeping easy access?

[SloppyDogDrool]

I have a pole building with roof trusses and studded walls to hold hardiplank siding. I prefer to keep walls and ceilings easily accessible to run wires or for whatever I need. The walls I'm just planning to hang insulation between the studs and let it exposed. The roof is my object of concern. I could cut an access panel but the joists are very cramped if a person had to walk between them. Seems like I always want to add another outlet, an airline or something and I prefer to run most of what I can through the ceiling. It's much easier and I can drop it where I need it.

So how can I insulate the ceiling and still keep it accessible from below? Nailing or screwing up the thin insulated foam board with the aluminum surface was a thought. Easy to take down and re-seal with tape but not much r-value.

Any other thoughts or suggestions?

 

[jklingel]

They make (allegedly) air-tight ceiling access ladders for houses. Would that work? I'd not use one in a house, as I don't trust the "won't leak" part, but for a shop I'd think they'd be fine.

 

[yevangelis]

2 inch foamboard, foil facing, screw each sheet on with 5 screws, real easy to remove any time..