Totaling qtys from multiple tabs

On the attached spreadsheet, I have several different types of structures that I am using for a project. Each structure type has its own tab, but these structures all use some of the same materials and I would like to be able to set up the fourth tab to list out all part #s that are required and to total the quantities of each part required. Is there a way to set this up to populate automatically based on changes to the quantities in the first 3 tabs?

Thanks.