How to use the assessment tool for damp and mould

 Enter the internal air temperature and relative humidity into the calculator, together with the surface temperature where this is known. 

The calculator will then estimate key psychrometric values, including vapour pressure, dew-point temperature and surface relative humidity, helping to indicate whether the measured conditions may support condensation or mould growth.

The results can be used as an initial assessment aid only and interpreted alongside the building fabric, ventilation, heating, moisture generation and any visible defects before reaching a diagnosis.