- Concerning which elements should be allowed to be tagged, by logic, this tag building=ruins should be allowed on unclosed lines (ways) since it is very probable that the elements of the ruin are most often partial remnants, like walls for example. Sometimes the original shape of the ruin can't even be known/guessed. A relation can join all those elements to gather all relevant common tags. --SHARCRASH, 9:50, 14 December 2016 (UTC).
Description and Usage of the building=ruins tag
It seems as if only the English OSM Wiki describes the usage of this tag in this way and meaing - for sham ruins, buildings which were constructed as ruins.
The same tag is described in (all) other languages in OSM Wiki as buildings which are ruins because they were abandoned or destroyed (in wars or by catastophries). The German Wiki has (in my opinion) a good and detailed description. In some conflict zones or former conflict zones of the word building=ruins and in a number of other countries with ruins without a special historical importance is used this way.
After I think tht the Wiki should describe and explain the usuage of a certain tag as it is used, I would like to recommend to change the English text. abandoned:building=* should only be added to building=ruins if the (former) nature of this building is known. --Ukundji (talk) 09:03, 28 August 2018 (UTC)