Window replacement costs in St. Louis

Outside its historic districts, the City of St. Louis usually treats a window swap as a no-permit job. The Building Division lists replacing or repairing existing windows and frames as work that usually doesn't need a permit, as long as nothing about the opening changes. That covers homes up to four units, plus storm windows and new glass.

A City Historic District or a City Landmark is the exception. There, windows need approval, and the same page says that in most instances the Cultural Resources Office requires a building permit even though the building code doesn't.

Lafayette Square is one of those districts, and its standards go further. A window on the main street-facing wall has to be repaired and kept, or replaced with one that copies the original. It has to be all wood or clad wood you can paint, with the same muntins, the same number of panes and the same way of opening. Metal-clad wood isn't allowed on that front. Neither is a new sill and jamb set inside the old ones, which rules out an insert-style window. A smaller window in the original opening is out too.

Double-pane glass can work if its outer face sits back from the face of the sash to match the original, at least 3/8 inch when the original depth is unknown. Tinted and reflective glass are banned. On side and rear walls, vinyl is off the table except to repair existing damage, and a secondary wall within 10 feet of a public sidewalk has to use wood too.