Without Walls

The defining feature of skyscraper is that a structural frame* carries all of the loads imposed on a building by gravity, wind, and earthquakes – usually called a skeleton frame. The phrase “curtain wall”, which long predates the construction of skyscrapers and meant simply a wall not carrying interior floors (as in a fort), was repurposed to mean an exterior enclosure wall of a building that has a load-carrying frame.

In the early days of skeleton framing, a lot of press focussed on the amazing lack of walls during the construction of skyscrapers and on the fact that the masonry walls, which are as solid in appearance as anything in construction, were no longer needed.

The non-structural nature of curtain walls is on display every time a new skeleton-frame building is constructed. Sometimes you get a glimpse during renovation. The photograph below shows a redevelopment project in Rochester, New York. The upper walls need some repair, but are completely undisturbed by the demolition of the walls and interior fittings of the floors below.

*I’m using the word “frame” a little loosely here, so that it includes renforced-concrete shear walls.