So I'm still trying to perfect my fondant technique, but I keep running into a problem when I put the fondant onto the cake. It seems that the weight of the fondant forces my filling out the sides and then I have rippling and bulging. I am using a BC barrier but the problem remains. Any suggestions? TIA!

Try watching how much filling you are putting between the layers. Too much will cause the sides to bulge, even with the cake dam. Also, you can try to lightly press on the cake (to help settling) so any bulging you can scrap up and smooth out before you cover. If times permits, I fill my cakes the night before, crumb coat then allow to settle overnight before covering in fondant.
From time to time I still have some bulgin spots, but with a few "creatively placed" decorations or embellishments, no one knows the wiser!!
Best of luck,
Jaime

Chill your cake before applying fondant.

Is your dam tall enough? Wide is good tall is essential.

Be sure your cake is sitting on the table as opposed to sitting on the turntable because the extra fondant can pool on the table and stop stretching down down down. If it's on the turntable it has more room to stretch and pull.

How thick are you leaving the fondant?

Trim some off before applying it. Don't roll out googobs more than necessary.

Fond aunt thoughts for you.

signed
Aunt Kate

I always use Swiss Meringue Buttercream for my cakes but regular BC may be even better as it tolerates warmer temperatures. Also make sure you smooth the BC really nice that way there are no imperfections. Do you place your cake in the refrigerator for a while before putting on the fondant? I believe this will help you with this problem. As you place your fondant on top of the cake, always smooth the top part first then work on the sides as you drape open/down the left over that hangs and cut away at it so it doesn't pull. Hope this will answer your question

I am wondering if it has anything to do with settling issues, filling and bc not thick enough, support dowel lengths not long being long enough.
Cake needs to settle to allow it to sink a bit with gravity- Indydebi posted how to force the settling issue by placing a tile on top to squish the cake so it won't settle later under icing and fondant.
If your fillings are not stiff enough then they will still squish out. Make sure they are stiff. Make sure you are not putting to thick a layer or too much filling.
Your supports should be long enough that the top tier rests on the supports and not on the cake below it.

Thanks for all of the suggestions. I love the suggestion with the tile...smart! How thick/thin do you typically roll your fondant before application?

i think its supposed to be about 1/8 inch ?? i had serious bulging issues until i got my agbay, now instead of one big huge tort with filling i have like 3 or 4 really thin layers of filling which means none bulges out of the sides as they are thin scrapings. i know its expensive but its totally worth it to avoid the dreaded bulge. also the tile method or even just pressing down firmly to get any air bubbles out, et c works as well.

for the impatient -- tile too slow for me.

dam -- about 3/4" from edge -- good and stiff

then big ol' cookie sheet on top of stacked layers.

spread fingers far apart and push down firmly, evenly and slowly on the sheet until the dam icing starts to peek past the edges of cake all the way around. press too fast and you'll split the cake -- I count 10secs off as I press.

release

give cake time to recuperate from being squished -- about the time it takes to load the big ol icing bag so you can crumb coat (dirty ice as Buddy says).

the proceed as normal with crumb coating and fondant

once I started doing thing in addition to all the good advice about thin fondant, do it counter top, etc, I haven't had any problems with bulges and can get on with it faster.