This was in the publish 52 Notes:
House Placement Changes
This publish implements several changes to prevent house placement exploits.
15 day character age requirement to place or trade a house
Water barrels/magic fields/etc will no longer block house placement
When a house is placed on top of a moongate, the placer will get a message about placement being blocked, and the moongate will be destroyed (at both ends.)
IDOC behavior (houses that collapse through decay)
When an IDOC drops, housing cannot be placed on the lot for a random amount of time
Items that drop from the IDOC will have protections against scripted looting
House placement tool will have a cooldown if used too many times in a given time period
Must now wait one hour after building a home before demolishing it (previously 15 minutes)