Wedding Tips: Wedding Cakes need good foundations!
You would think a wedding cake maker would get this right for you. To be fair, heat in Wales is not normally a concern. However we did have a couple of rather hot days one weekend, and found two consecutive weddings had their wedding cakes collapse. They literally caved in under their own weight.
One we managed to re-ice and re-assemble. The other was so squashed we had to cut the lower sponge tier up in the kitchens away from the eyes of the guests.
We understand this is because of a trend to save money by having the base made out of sponge, and the fruit levels reserved for the smaller upper tiers. Pre-recession, weddings would normally have the heavier fruit filling on the larger base tier of the cake, providing a more solid base for the upper tiers. Adding heavier upper levels to a soft and weaker lower level is architecturally unsound.
Supporting a weak base tier with pillars internally should in theory get around this problem - yet both the collapsed cakes had internal pillars. These toppled over sideways within the cake, having nothing solid in the sponge and melting icing outer to hold them upright.
So consider the internal filling of your cake carefully, avoid travelling with your cake in a hot car (find a way of keeping it cool). At the venue, do not have your cake stand in direct sunlight. We have a special cake stand area in our Conservatory away from the windows, and in the shade, where you can place the cake, but note even this is reasonably close to our underfloor heating vents.
Read more on weddnig cakes here.