# Engine Error when making 2nd story bulding

**URL:** <https://discourse.stonehearth.net/t/engine-error-when-making-2nd-story-bulding/19108>\
**Category:** Other Reports\
**Tags:** no\_longer\_applicable\
**Created:** [January 13, 2016, 7:21am UTC](https://discourse.stonehearth.net/t/engine-error-when-making-2nd-story-bulding/19108 "2016-01-13T07:21:41Z")\
**Posts on this page:** 1\
**Showing post:** 5

<div class="post-metadata">

**Author:** ![Smuggy](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.stonehearth.net/smuggy/32/25956_2.png) [@Smuggy](https://discourse.stonehearth.net/u/Smuggy)\
**Post date:** [February 3, 2016, 10:37pm UTC](https://discourse.stonehearth.net/t/engine-error-when-making-2nd-story-bulding/19108/5 "2016-02-03T22:37:33Z")

</div>

I got hit with 4 errors all together while trying something abit more elaborate.

In order;

```auto
release-491 (x64)
...nehearth/components/building/building_component.luac:138: attempt to call method 'layout' (a nil value)
stack traceback:
	[C]: in function 'layout'
	...nehearth/components/building/building_component.luac:138: in function 'layout_roof'
	stonehearth/services/server/build/build_service.luac:219: in function 'grow_roof'
	stonehearth/services/server/build/build_service.luac:210: in function 'cb'
	stonehearth/services/server/build/build_service.luac:304: in function 'do_command'
	stonehearth/services/server/build/build_service.luac:210: in function <stonehearth/services/server/build/build_service.luac:209>

```

```auto
release-491 (x64)
c++ exception: lua runtime error
stack traceback:

```

```auto
release-491 (x64)
...hearth/services/server/build/build_undo_manager.luac:6: assertion failed!
stack traceback:
	[C]: ?
	[C]: in function 'assert'
	...hearth/services/server/build/build_undo_manager.luac:6: in function 'begin_transaction'
	stonehearth/services/server/build/build_service.luac:303: in function 'do_command'
	stonehearth/services/server/build/build_service.luac:210: in function <stonehearth/services/server/build/build_service.luac:209>

```

```auto
release-491 (x64)
...hearth/services/server/build/build_undo_manager.luac:108: assertion failed!
stack traceback:
	[C]: ?
	[C]: in function 'assert'
	...hearth/services/server/build/build_undo_manager.luac:108: in function 'clear'
	stonehearth/services/server/build/build_service.luac:44: in function 'set_teardown'
	stonehearth/call_handlers/build_call_handler.luac:7: in function <stonehearth/call_handlers/build_call_handler.luac:6>

```

Building : [Imgur: The magic of the Internet](http://imgur.com/gAa1fFC)

Errors appeared when i tried to put the 2nd roof on. After that all building functions stop working and i have to relog to fix it but when i load back into my save i get the error message;

```auto
release-491 (x64)
...nehearth/components/building/building_component.luac:124: attempt to index local 'entity' (a nil value)
stack traceback:
	radiant/modules/events.luac:84: in function <radiant/modules/events.luac:81>
	...nehearth/components/building/building_component.luac:124: in function '_trace_entity'
	...nehearth/components/building/building_component.luac:37: in function '_restore_structure_traces'
	...nehearth/components/building/building_component.luac:17: in function 'obj'
	radiant/modules/events.luac:44: in function 'instance'
	radiant/modules/events.luac:98: in function <radiant/modules/events.luac:96>
	[C]: in function 'xpcall'
	radiant/modules/events.luac:96: in function <radiant/modules/events.luac:86>

```

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_[View the full topic](https://discourse.stonehearth.net/t/engine-error-when-making-2nd-story-bulding/19108)._