Insulation, Radiant and Vapor Barriers - Eight inch attic - rigid board?

I have an eight inch attic which is under-insulated. If I blow insulation in the ventilation will be insufficient and I'll get condensation and rot (confirmed by a professional).

Someone mentioned that I should remove the current insulation and replace it with a couple layers of rigid board (with appropriate vapour barrier). I have no access to the attic so I'll have to cut holes in my ceiling and patch them up when I'm done so I want to make sure this is worth it and that I do it right.

Any comments? Is this worth the cost and effort?

I have the same problem no door to the attic in the house so what l did is replaced my roof vents with turbo vents that turn in the wind the hole in the roof is a little bigger and the turbo vent helps move the air around .
I would get more insulation blown in but do not pack it in tight so the air can flow through the attic.
some people do not realize that the cheep vents that on the roofs of houses do not last forever thay get clogged up too and need to be replaced

:confused: You dont say what you have up there for a roof or attic. Is it 8"2X10???Do they run to the ridge?Could you put a ridge vent there and vents from the over hang. take the ceiling down.Put the foam rafter vents up to the roof then the insulation paper side to the room. Put a 4 mil poly V/B over it then the new drywall ceiling.
On the turbine vents they are outlawed here. They let water in sometimes .When its real hot and no wind they dont do anthing. Big wind they blow off. Best bet is a power vent fan on a tstat If you have the room and set up for it.

ED ;)