Through leakage in the building envelope there is a penetration of air, water vapor and particles. The degree of leakage of air can be quantified by existing methods. However, the location of adventitious openings is often not known. In order to overcome the limitations in existing methods, a non-contact and non-destructive method based on ultra-wide bandwidth radar technology is suggested. A test-bed is designed that can measure with different polarization to be able to detect flaws in different directions. Initial measurements shows promising results for further development of the method of using radar images to find leaks in building elements.