You didn t mine out a mountain you mined out a hill.
Rimworld pops not building roofs.
They would not see each others roofs.
If it s an overhead mountain collapsing colonists will be buried alive.
When building a large room 10 x 10 tiles i had the same problem the roof being missing exactly in the middle and i absolutely couldn t get them to build one.
Roof collapses cause injuries to colonists and damage items.
If that distance is more then that then you will only get a partial roof around everywhere but the position where it lacks enough support.
A roof collapses if there s no support rock wall within 6 squares of the tile.
So i was building an indoor farm next to two geothermal generators which were unroofed by zone while the farm was being built and after the construction is done the farm won t roof over.
I have this stockpile area with roof upon it.
Designating such an area will also remove existing thin roofs and thin rock roofs when applied but thick rock roofs will remain intact.
I also tried to remove zone and roof and rebuild from scratch but the problem persists.
Once he she is inside the room forbid the door so the colonist can t leave.
Make sure to remove all electronics that short circuit in rain then use the no roof tool in the zone options.
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The weird thing is that i am not able to build roof on that square.
A roof will not be fully built in a room that is more then 11 blocks between two parallel sides.
You can avoid a collapse by either not mining the whole thing or building a wall to support it.
As long as there is no other work to be done in there with a higher priority the colonist will finish building the roof.
I tried roofing over the geothermal buildings but when i dezoned it it just went from unroofed to outdoors.
Green build constructed roof area red remove constructed roof area option settings to enable disable auto roof building power outputs and roof cost adjustment sliders compatibility.
2 roof construction is a low priority.
This means that the largest square room you can have is 10x10 internal.
You can select one of your colonists and then right click inside the room and prioritize building roof should be an option.
A roof will collapse if the last supporting wall or rock is removed whether by mining deconstruction or destruction.
I would not install other roof building mods with this one.