Ireland has the highest per capita home ownership rate in the world at nearly 85%. The tradition in Ireland has always been to build or buy a home and live there all your life. Only since the 1990's has this "build for life" ethic started breaking down. For the first time, moving around to get better jobs and moving up to get better homes has become common.
You don't need to be a citizen to buy land or a house in Ireland. As for building a new house, many counties are being very stringent about allowing non-locals to build new houses in green field sites in the countryside. Buying an existing home raises NO such problems - you can buy existing country homes without any planning permission.
I've been covering the housing market in lots of news articles, so I'd suggest looking there for articles on boom-bust possibilities, government responses to the problem, and the like. (Note: the Full Site has an archive of all the newsletters, the free site provides access only to the current issue.)
The summary is this: the country is in the aftermath of its greatest economic boom since the first hollowed out log arrived in-country about 12 millennia ago. House prices rose accordingly. An annual immigration of up to 70,000 mostly affluent immigrants to Ireland boosted prices, as did two income families. Dublin sprawled outward and anyplace within an hour's drive experienced significant inflation. The rest of nation followed the upward path.
Since 1995, house prices have trebled or even quintupled. In Dublin, many have risen by even greater multiples. Building costs, by contrast, have risen only by 75%. Ergo, someone's pocketing a bunch of loot. Hmmm? Who could that be? It's no wonder builders and investors swelled the building rate to 93,000 units in 2006.