Hi Katog
All pigs need is somewhere dry and warm that they can't destroy. Whatever you built before will probably be fine, just keep it topped up with lots of straw when it's particularly cold.
Our pigs all live in home made arks with metal roofs and floors on skids. I know of someone in Orkney who keeps his pigs in shacks made of old pallets nailed together which does just fine.
Gillian