Structure inspection with L-band radiometers

Case study: water seepage through the Crypt roof at Colonia Güell, and comparison with GPR measurements.

The Crypt is a well known building constructed by the architect Gaudí at Colonia Güell near to Barcelona. The original roof had been suffering from water leakage (infiltrations) when a team of architects decided to build a new roof over the original in order to protect it. Unfortunately, the problem was not solved and water continued to seep into the crypt. A new diagnosis of the issue was needed.

Balamis ground version radiometer was mounted on a pushcart to retrieve the measurements. The Colonia new roof is made from compact ceramic without metal reinforcement and the material is impermeable to water (no water pooled inside or under the roof). In these conditions passive microwaves penetrate between 20 and 25 cm.

The image on the left shows moisture distribution as resolved by the Balamis radiometer. A clear concentration map reveals the key points of infiltration. This type of measurement is not possible using alternative technologies like thermographic cameras since moisture presence was deeper, and GPR did not prove to have enough sensitivity to retrieve its presence (see image bellow).

The ability to identify water seepage helps to plan the most suitable corrective action and avoid very expensive repairs in the future.

Author: Roger Jove

Follow us on Twitter and LinkedIn.