There are still thatched roofs, big houses, little houses, but we saw more and more regular tile used for roofing. Here is a large home, thatched roof, with the stone structure plastered and whitewashed.
Thatch turned out to be good against weather, but bad against those seeking to evict the inhabitants of the house. Thatch could be used for concealing items of value, leading the overlords and others to set fire to the place. One reason for burning poor renters out of their houses during the clearances in Ireland and Scotland years ago, see http://rootsweb.com/%7Epictou/clearncs.htm, was to access any bits of gold or other valuables. Occasionally as well, perhaps the insects and rodents up there required a redo.
Scots and Irish have been intermingling back and forth since the 5-7th centuries, says the site. Mc and Mac alone did not denote which was which, and the Irish were the more ancient. Read of the race of Dalraida, Irish, at this Scottish site, http://www.heartoscotland.com/Categories/History2.htm
County Clare, Cottage, thatched roof, near Galway, Ireland
Thatching is a live industry. Find thatching techniques and instruction at http://thatch.org/.
Thatching is also available in US for new home construction. See http://thatching.com/faq.html for thatching in North America. It is more popular in the UK, see http://www.buildingconservation.com/articles/thatchrf/thatchrf.htm.