Unfortunately, there isn't an automatic way to handle ice within MecaStack; however, it is something on our wish list. There are a couple of ways you can try to handle it. The easiest would be to enter it as insulation/refractory with a density of ice and specify that it is external to the stack. This will add the weight and wind area. Typically you only have to check for ice for a reduced wind speed and so you might want to make a separate analysis for the ice case with the appropriate wind speed. Refer to the standard (ASCE 7, etc..) for the wind speed that needs to be considered in conjunction with ice.
Ice is more complicated. Ice adds weight and wind area, but also the code specifies a reduced wind velocity that is supposed to be considered to act with ice. Here is what I have done in the past:
1) I take my file and make a copy of it and indicate that file is for ice.
2) Add refractory to the external shell. The density and thickness will correspond to the density and thickness required for ice for your location.
3) Ladders and Platforms are a little more complicated. You have to decide how you are going to handle the ice. If you are going to figure it applies to every member, then you will have to work out how much that is going to increase weight and wind area for the ladder and also the platform. You can increase the weight used for the ladder and platform to account for the ice. You can also specify a custom wind area to account for the extra wind area. This is a lot of work. Another approach might be to assume that the weight and wind area are going to increase by some conservative factor (1.5 or 2) and then just increase both by that amount.
4) Determine the reduced wind velocity that is required and enter that wind velocity
In most situation we have found this largely to be an academic exercise because it doesn't usually control the design of a stack.