After I stack my cakes with foundant I noticed that the top tier sinks on the prior one.
I don't know if i am explaining it clearly.

Could it be that the foundant is to heavy? Please experts help me

Did you use the dowel supports?

I just used the cardboard between teirs..

maybe, the cake is not sturdy enough for fondant...

bobbie

You nees to use dowels

cake is really heavy and soft at the same time. You have to have SOMETHING under the cardboard. I have heard of people using straws, but I use dowels. I also NEVER use cardboard, as it absorbs moisture and gets soggy. I use foam core.

You have to use dowels of some sort to support the tier on top. The board will never be strong enough.

Check out this video