Is it smart to lay plastic under a pier and beam cottage and should I close it in?
...vaporation from the ground.
Some things to consider whether or not you close it in –
If you really don’t go often in winter then it may not be worth the cost and effort of jacking it up to build a crawlspace, but if you do, see here on how to insulate a crawlspace properly to avoid mold and heat loss. And no, we would ...