I have had this happen to me twice now and once is too often. I have had to strip off the buttercream on the cakes and start over. I made the bc same as usual, crumb coated the cakes, waited for them to settle and crust over, etc. etc. During transporting or just before I loaded one in the car I noticed everthing on the sides were starting to sag. The more I drove the more things started to slide off to the base. It is hot here in San Antonio but I deliver a lot of cakes in the same conditions without a problem. The first cake had a very thick bc icing on the sides and I blamed that. On the second one it was chocolate bc and the top was starting to slide down the sides. Any suggestions?

Do you use any meringue powder in your buttercream? (I have said this several times now, I hope I am not wearing folks out!_ But, I use all crisco when it is hot out like this, and I put a little extra meringe powder in the icing along with Stay Ice and I have not had any problems with the buttercream melting or being too soft. It seems to work beautifully for me.

I just drove a 3/4 crisco - 1/4 butter buttercream cake in 105 heat it was fine - it was even in the sun a little bit during the 45 minute drive.
Maybe the icing was a little loose - and the weight took it down - I'm sure the heat didn't help the matter.

i do use meringue powder. Perhaps I should use Stay Ice also when the weather is this warm.

Thanks for the help

What is Stay Ice? I haven't heard of that before.

It is an icing stabilizer. HERE is where I got it and some info on it.