Layover occurs when several areas of different altitudes are located at the same slant range from the SAR sensor. In layover, the sensor receives a mixture signal from these areas. In this paper, mixtures of two contributions of different altitudes are considered. Two models -one using interferometric data and one using full polarimetric data- are compared on building height estimation. It is shown that they both successfully separate the mixtures on high resolution PollnSAR images from the RAMSES sensor (ONERA). Prom full PollnSAR data, an optimal interferogram is generated. Mixtures in this interferogram are partially separated.