Pole barn ceiling insulation

[arewethereyet]

The basics:
Central Oregon, high desert, pretty dry
Cold Winters!
48'x42'x16' Pole barn with concrete floor
Metal Siding & Roof
Roof looks similar to this link:
http://www.xsrpms.com/~racerx/pb3/pb3_roof.jpg
But my roof has a fiberglass reinforced vapor barrier between the top of the roof purlin and the metal roofing

What I'm trying to achieve:
Pay someone to insulate ceiling
Low Cost
I don't want the insulation to get damaged due to vapor barrier being in wrong spot, no ventilation, etc.

Option 1:
Use hangers and 2x6 to span between the bottom cords of the trusses.Then insulate with unfaced batts, run twine over insulation and cover with FSK paper.

Option 2:
Insulate between the roof purlins, and then cover with twine and FSK paper.

End result would look similar to this:
http://steelbuildinginsulation.com/Images/PoleRoofInsulation.jpg

My concerns with this option is that I have a vapor barrier touching or pretty close the the roof insulation when using an R19 batt. If I went with an R11/R13 batt, there would at least be some room for airflow.

Any thoughts would be appreciated.

 

[anthony666]

i was gonna say 'spray foam' .. then i noticed you said 'low cost'

 

[arewethereyet]

i was gonna say 'spray foam' .. then i noticed you said 'low cost'

I wish!