Corrected entry: Jarvis tells Tony that crews have arrived with cranes to start removing debris to reach the basement lab. With the number of suits stored there why couldn't the suits just dig or blast their way out under remote control? 99% of the house fell into the ocean so there wasn't so much rubble that the suits couldn't free themselves.
Gillbillvolume1
28th May 2013
Correction: A majority does fall into the sea but not 99% - the rest collapses onto the basement. Stark probably had some blast proof doors to keep people from getting in, so his armors wouldn't be able to blast out.