If your inactive account hasn't reached the 90 day mark, then re-activating the account will keep it from going into IDOC mode.
However
If it's a grandfathered house, then you must open the front doors.
" Players who owned multiple "grandfathered" houses prior to July 2002, regardless of whether the multiple houses are on different shards or all on the same shard, are allowed to maintain these houses, but they will need to be refreshed manually. Although grandfathered houses will not decay in the same manner as primary houses, these players have the option of declaring one of their houses as their primary house, which condemns all others owned by the same account. "
If you activated your account
before the 90 day mark, your house has still become condemned, and you've waited 24 hours, page a GM and have them come and fix it for you.
" Note: Once you reactivate your game account, it can take up to 24 hours for the houses on your account to reflect this change. In other words, if your house has become condemned because your account was inactive, it can take up to 24 hours after your account becomes reactivated for your house to become un-condemned. "
More details on
http://www.uoherald.com/guide/guide.php?guideId=141