A tied house, in the traditional sense, is a pub that buys its beer exclusively from one brewery.
The Pennsylvania Liquor Control Board does not allow them. When father-and-son William and Chris Leonard of the General Lafayette Inn, a Lafayette Hill brewpub, sought to open such a gastropub downtown, they relied on William's wife, Rose, and son Jonathan to obtain the restaurant license.
So that's why the General Lafayette and the cozy Tiedhouse - which opened last week in the ground floor of the CityView Condos near the Art Museum (2001 Hamilton St., 215-561-1002) - are separate operations. (Why didn't they just call it "the Loophole?")