# Custom building - error corrupts design/building/demolishing of structures
**URL:** https://discourse.stonehearth.net/t/custom-building-error-corrupts-design-building-demolishing-of-structures/33041
**Category:** Bug Reports
**Tags:** building, a22r763
**Created:** [December 18, 2017, 1:44am UTC](https://discourse.stonehearth.net/t/custom-building-error-corrupts-design-building-demolishing-of-structures/33041 "2017-12-18T01:44:46Z")
**Posts on this page:** 1
**Page:** 1
### Author:  [@RoxStar](https://discourse.stonehearth.net/u/RoxStar)
#### Post date: [December 18, 2017, 1:44am UTC](https://discourse.stonehearth.net/t/custom-building-error-corrupts-design-building-demolishing-of-structures/33041/1 "2017-12-18T01:44:46Z")
Build a simple building size 5x5. Put a bed in a corner of the building. I tried to raise the walls and got the error’s as stated below.
Since then I delete the building through conventional means. I can also not build or design any new buildings. Even after using console commands, there is no way to design or build a new building.
Sadly enough, I forgot to save and tried to reload the game.
Although the cause might be that the walls had to be raised trough the bed this time, this happened to me occasionally before.
The errors were as following:
**First Engine Error**
release-763 (x64)
stonehearth/components/wall/wall\_component.lua:366: attempt to index a nil value
stack traceback: [C]: ? stonehearth/components/wall/wall\_component.lua:366: in function ‘connect\_to\_columns’ stonehearth/services/server/build/build\_service.lua:1266: in function ‘init\_fn’ stonehearth/services/server/build/build\_service.lua:538: in function ‘\_create\_blueprint’ stonehearth/services/server/build/build\_service.lua:1264: in function ‘\_create\_wall’ stonehearth/services/server/build/build\_service.lua:1251: in function ‘\_add\_wall\_span’ stonehearth/services/server/build/build\_service.lua:1081: in function ‘visitor\_fn’ stonehearth/lib/build\_util.lua:817: in function ‘grow\_walls\_around’ stonehearth/services/server/build/build\_service.lua:1080: in function ‘grow\_walls’ stonehearth/services/server/build/build\_service.lua:1052: in function ‘cb’ stonehearth/services/server/build/build\_service.lua:1583: in function ‘do\_command’ stonehearth/services/server/build/build\_service.lua:1051: in function \
**Second Engine Error**
release-763 (x64)
c++ exception: lua runtime error
stack traceback:
**Third Engine Error**
release-763 (x64)
…ehearth/services/server/build/build\_undo\_manager.lua:414: assertion failed!
stack traceback: [C]: ? [C]: in function ‘assert’ …ehearth/services/server/build/build\_undo\_manager.lua:414: in function ‘clear’ stonehearth/services/server/build/build\_service.lua:121: in function ‘set\_teardown’ stonehearth/call\_handlers/build\_call\_handler.lua:25: in function \
**Last Engine Error**
release-763 (x64)
…ehearth/services/server/build/build\_undo\_manager.lua:46: assertion failed!
stack traceback: [C]: ? [C]: in function ‘assert’ …ehearth/services/server/build/build\_undo\_manager.lua:46: in function ‘begin\_transaction’ stonehearth/services/server/build/build\_service.lua:1580: in function ‘do\_command’ stonehearth/services/server/build/build\_service.lua:419: in function \