For the first time in its 20-year history, Quantum Theatre has had to delay the opening of a show.

That doesn't sound so impressive unless you know that Quantum is a theater company homeless by choice: It creates a new theater space for each show, usually in nontraditional venues, whether cemeteries, old swimming pools or vacant warehouses. That requires a lot of retrofitting the built environment, and also a good bit of negotiation with various property owners and government entities.

Maria, a sort of surreal tango opera by Astor Piazzolla, is being staged in the East Liberty YMCA. But this time, unlike all the others, Quantum ran into some problems with building codes that were not fixable by curtain time last week. The issues is accessbility for patrons with physical disabilities.

In a statement, Quantum said it would get the necessary waiver this week from the Pennsylvania Department of Labor & Industry's Accessibility Advisory Board.

So Maria now opens on Fri., April 1, and artistic director Karla Boos has scheduled new performances to make up for the lost week.

Maria will now be  performed April 1-17, with a show every single evening except April 11. The shows on April 4, 5, and 12 are at 8:30 p.m., and on Sat., April 16, there will be two performances, at 7:30 and 10 p.m.

Quantum can be reached at 412-697-2929 and www.quantumtheatre.com.