Constructed dungeons can be built inside a subterranean space or buried under an artificial mound. The walls provide more support than natural spaces or excavations, and the spaces can be more regular and efficient. They are very stable unless the walls or pillars are damaged or broken through.
When conditions could trigger a collapse, roll a d6 and subtract 1, or 2 for supports. On 5+, a 10 foot by 10 foot area collapses. As for excavations, an earthquake add +2 to the roll. Unlike excavated areas, this doesn't trigger a cascade of checks for adjacent areas unless the size of the area is outside these standards:
- Extends 40 feet in both horizontal directions;
- Extends 20 foot in one direction and 80 feet in the other;
- Extends 10 feet in one direction, 160 feet in the other.
The main construction techniques are:
- Brick: Easier to damage. If a man-sized or larger creature is thrown against a wall or column with enough force to take damage, a damage roll of 6+ will also damage the wall. If this happens again, the section collapses.
- Masonry: Larger, irregular masses of stone are harder to damage. Only deliberately breaking walls and columns will weaken or collapse an area.
- Large Blocks: Big cubes of stone at least half as tall as a man. Very hard to damage (-2 to roll.)
- Cyclopean Blocks: Like Large Blocks, but on a titanic scale. Impossible for man-sized creatures to damage using normal methods. An earthquake may damage such a construction, but it would take a second earthquake to trigger the collapse roll.