Overlay of several layers

Is it possible to find out common area of several layers in SNAP

If all layers are in the same product, your can use the mask manager:
layer1 AND layer2 AND layer3

If they all belong to different products you can use the collocation tool to make one stack and analyze the collocationFlags band which tells you the overlapping area.

I have data of sentinel 1 of several dates. I did binarisation of flooded and non flooded area… now Flood area changes over time. I want to traceout the permanent flood water pixels which are common to all layer. I will try doing with the method you said and will inform

then stacking the products is a good choice, either with the collocation or the Create Stack module, then proceed with the Mask Manager to define logic descriptions for the flooded areas of different dates.

I have stacked product… But I’m not getting with where to define logic description… Is it in band maths???

please send a screenshot of your product explorer containing the stack with the names of the stacked bands within. That helps us understand how your data is organized.

It could now look similar to this where each band represents a date and is a binary raster with 1=water and 0=no-water

I did it with raster band math and it works. After stacking. Thank you for your help