...?

J

Or do it yourself

Dew Point Temperature is about equal to Temperature - ((100-Relative Humidity)/5)

Or the other way around

Relative Humidity is about equal to 100 - 5(Temperature - Dew Point Temperature)

There was a bit in this weeks comic about the relationship between temperature, heat capacity, specific heat capacity, volumetric heat capacity and thermal conductivity, was related to drying but the same maths. It is still on the shelves.

http://www.newscientist.com/

Posted By: James Norton...I could just spread sheet it a plot temperature vs RH...?

Yes, you could do that if you know the relevant properties of the materials. You'd need the thickness, thermal conductivity (often called lambda or k in W/(m·K)) and vapour permeability (in GN·s/(kg·m), sometimes written as the equivalent MN·s/(g·m)) for layers with noticeable thickness and the vapour permeance (in GN·s/kg or MN·s/g) for layers of negligible thickness like membranes.

As you say you could plot the temperature profile. However, rather than deal directly with RH you'd need to work out how the vapour pressure is distributed across the wall by finding the vapour pressures on the inside and outside and the permeance of each layer then working out the vapour pressure drop across each in a manner analogous to the way you'd work out the temperature profile knowing the thermal resistance of each layer.

Knowing the temperature and vapour pressure at each interface you would then work out the RH and so get an idea of the condensation risk.