Building Condensation

[CScottFlanagan]

A client purchased an existing pre-engineered metal building. The walls and roof have about 4" vinyl-backed fiberglass insulation, which is typical in the metal building industry. The client has what we thought were roof leaks, but there appears to be a more serious and widespread problem with condensation.
He's trying to maintain 76 degrees F, and 50%-60% Relative humidity. I know the importance of the vapor barrier in keeping the moisture out of the insulation.
Can anyone recommend a good reference publication on how to calculate the suitability of the roof insulation for the conditions?

 

[imok2]

Try this:

http://www.r-control.com/products/building_products/building/roofing/pdf/roof.pdf

 

[SErgini0]

I would recommend ASHRAE's guides if you are in the US, or CIBSE's if you are in the UK.