Cave can be used for Refuge. Cave is related to Opening. Opening is related to Operation. 
House have Roof. Roof is related to Warehouse. Warehouse is related to Inventory. 
Refuge <--UsedFor-- Cave <--RelatedTo--> Opening <--RelatedTo--> Operation 
House --HasA--> Roof <--RelatedTo--> Warehouse <--RelatedTo--> Inventory 