Tŷ unnos, the Welsh folk tradition of building a house in one night

Watching the special program ‘24 Hour Build Special’ from the seventh season of ‘George Clarke’s Amazing Spaces’ (from the English public broadcast television Channel 4 in 2018) I learnt about ‘Tŷ unnos’, the Welsh folk tradition (shared with many other places in the world) of building a house in one night.

The tradition says you can build a house for free on common land if it only takes you a night.

Did you know about this tradition or something similar?

Photo credit: The Ugly House (Welsh: Tŷ Hyll) near Betws-Y-Coed, a famous example of a tŷ unnos (Steve Daniels CC BY-SA 2.0) https://commons.wikimedia.org/wiki/File:The_Ugly_House_near_Betws-Y-Coed_-_geograph.org.uk_-_2111697.jpg

Here the article in Wikipedia: en.wikipedia.org/wiki/Tŷ_unnosHere the program in Spanish: www.rtve.es/play/videos/…/6022018/