I'm having issues with my BC. It starts to crack once it sets. I use an equal amount of hi-ratio shortening and butter in the recipe. I usually put a crumb coat over the cake and chill it slightly before covering it with BC. Could it be too cold? It only seems to happen on sheet cakes. Could it be due to insufficient support? I would be grateful for any suggestions!
I found my were cracking due to not enough support. I have tripled by cake board. Little more cost; but has helped.
It might be the sheet-cake thing. I've found that the wilton boards don't hold up well to an actual iced and decorated cake. I even used two the last time, taped together, and it still bent on me after being decorated. 
So now I use either a cookie sheet or a cake base for it. More expensive, but worth it if the cake doesn't fall apart! LOL
Maybe add some corn syrup? This will add some elasticity after the moisture from your liquid evaporates 
Since it's happening all over but ONLY happens on sheet cakes, I'm gonna stick with it being a support issue. What I mean by that is that the board underneath the cake needs to be thicker. Sheet cakes are notorious for this.
If you want to add more liquid to your bc, that would be something to test as well, especially if once you add more thickness to your cake board you find it still cracks all over. Then you know it's no longer a support issue but a bc that is a little too dry. The liquid you add can be water or milk, whatever you would usually use in the recipe, about a tablespoon to start. Then if it STILL cracks, maybe another tablespoon. By doing it this way you are sure to get to the bottom of the cracking issue!
I hope that made sense - good luck!
Quote by @%username% on %date%
%body%