:Occurs underground when trying to add a tile to a building plan when the cave ceiling above would be too low for a single storey building. Mine the cave ceiling a little first, before planning this tile.
== External Tools See Also =={{External}}*[http://webdepp.sense-net.at/~toni/wurm/housecalc.php Web-based Calculator by Toni[Toolkits]]*[http://forum.wurmonline.com/index.php?/topic/75908-new-unofficial and unsupported house-calculator/ Windows / Java Web Applet Calculator by Warlander] which supports doughnut and multi-floor housesplanning tools.
== See Also ==
For additional housing creation inspiration
* [[:Category:Floors]]