The following measurement example illustrates a damage analysis of gypsum plaster that exhibited cracks and structural deterioration following a cycle of exposure to summer and winter conditions. The manufacturer suspected improper application and utilized thermogravimetric analysis (TGA) to compare the damaged section of the wall with a reference gypsum sample that remained crack-free after heating and cooling cycles.

The measurement revealed that the carbon and organic content of the “flawed” samples (represented by the green and blue curves) closely resembled that of the reference samples (indicated by the red and black curve). All samples displayed a similar level of mass loss, approximately 2%, in the temperature range around 500°C. However, a notable discrepancy emerged in the weight loss occurring at temperatures between 800°C and 900°C, where carbonates in the gypsum release carbon dioxide. In the case of the reference samples, there was a substantial 30% mass loss due to the released CO2, whereas the wall samples with cracks exhibited only 11% and 13% mass loss. This discrepancy suggests that the gypsum on the damaged wall had a lower carbon content than expected, implying that there was indeed an issue with the mixing of the gypsum plaster.

Interestingly, the analysis also unveiled differences in carbon content between the wall’s west-facing (weather-exposed) side and the east side of the building, further highlighting the critical role of gypsum composition in its performance and longevity.