[RPG] What happens if you Move Earth from under a big tall stone building


Our party is currently looking for a way of destroying or heavily damaging a castle-like mansion. It is a tall stone building, roughly 45×45 meters. While researching the ways of doing it, our druid recalled that he can Move Earth from under a castle. A 5th edition version of the spell is more thorough and mentions that you can lower the earth's elevation and that

If the way you shape the terrain would make a structure unstable, it might collapse.

However, it seems that 3.5 version of the spell can only move 10ft.-deep chunks of earth.
Will 3 casts of the Move Earth spell (e.g. 30ft. of earth gradually removed from under the half of the building) be enough to heavily damage or topple it? Or will our druid just create a Pisa-like landmark for the people living nearby?

Best Answer

1 cast of Move Earth will accomplish what you need. 3 casts of Move Earth will completely obliterate enemy defences

It used to be a common siege tactic to dig a tunnel (which with the battlefield engineering available at the time would be less than 10 ft.) under the enemy wall or tower, secure the ceiling with wooden supports... and light them on fire. The aim was to dig the tunnel under a load-bearing fragment of the structure, such as a corner. Removing earth veeery slowly would possibly leave the part of the structure directly above intact, but the connection between it and the rest of the building, the part sitting on the edge of your earthworks would be reduced to rubble.

FYI, enjoy an image presenting a brick building which suffered from earth settling due to mining activity. The ground settling happened over years and the height difference was less than a foot in height. Bytom's ruined building

Imagine what 10 ft. of difference would do to that wall.

Walls are made of crumbly materials and don't stretch well at all. Stretching a wall 10ft. downwards will definitely make it crumble in the seams.