Concatenating arrays using matlab guide

I am using MATLAB GUIDE to prompt the user to input some sound barrier dimensions and position it in a 3D space. The user has the possibility of adding a number of barriers and would like the values entered to be saved in an array and with each barrier insertion the new values will be added to those entered previously. I am using the script below, the only problem is that the values entered for the first barrier are not being listed. Any help please?

   Barriers = [];

BarrierSpecs = [varBarrierHeight, varBarrierWidth, varBarrierLength, varBarrierX, varBarrierY, varBarrierZ];

 Barriers = vertcat(Barriers, BarrierSpecs)

The above is in a callback function