I used Satin Ice, and at the base of each cake the fondant is buckling, for lack of a better word. It's almost like the cake's height shrunk, and now there's too much fondant so it's bunching up....kwim? This happened after the cake had been sitting out for a day after being covered with the fondant. The only thing I can think is that it's been 100 degrees here every day for the past week, and even though we have central air in the house, maybe it's just not cool enough? I ended up covering the cakes and putting them in the fridge this morning, and so far they seem okay - they don't seem to be buckling anymore but maybe that's wishful thinking. I'm worried about the long car ride they have to endure to get where they're going. I'm going to have to put them in coolers or something I guess.

Any ideas? Advice? Thanks, everyone.

I'm no expert, I don't know how to tell you to fix it, but the only time I had this happen was when either my icing under the fondant wasn't stable enough. Or, I rolled my fondant a little too think and it weighed too much and the cake settled a little.

Good luck! Aint summer heat great!

I had that happen before with one of my fondant covered cakes...

It ended up being because I needed to roll the fondant out thinner. Thankfully I was able to pull off the fondant from the cake without damaging it (besides doing another buttercream layer for touch-up) and because I had made an extra batch of fondant from the get-go, I rolled that thinner and used that on my cake.

It happened to me the other day, not in the house but in the car on the way over. My guess is that my buttercream started melting because I don't have ac in the car and it was 94 outside, and so the fondant sagged a little bit.

Your cake may have settled after you put the fondant on or something might ahve been pulling down on it. I have had that happen when I put fondant decorations on the sides before.

How long did you let your cake settle after you put the BC on and before you put the fondant on? I highly recommend sugarshacks fondant DVD if you are having problems. It show step by step how to get a nice smooth finish with no sagging or buckling.

it's from settling... I had that problem too when I first started using fondant. I didn't know that you had to let it rest several hours after filling/stacking before icing and applying the fondant.

Live and learn....

It also helps to use a cake board or the bottom of a plate to gently push the cake down after you've filled it but before crumbcoating. Kind of forcing it to settle faster.
Also, the fondant may have been a little soft and the heat and humidity made it sag. Sorry that happened. I hate when it does.

could be :

1) the cake was not firm enough
2) the cake was too "wet"
3) the fondant was too heavy
4) heat/humidity
5) your BC started to slide off your cake and took the fondant with it ( see #2 and 4)

I have had it happen many times, esp. on slanted or 3 layer cakes and I hate it too.