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Polystyrene Lightens the Load07-12-07 | News

Polystyrene Lightens the Load

The Central Library in Indianapolis, built in 1917 of Indiana limestone with a base of Vermont marble, is undergoing an expansion. About 20,000 sq. ft. of polystyrene foam is being installed as the foundation for the greenroof.

?EUR??,,????'??Lighten up!?EUR??,,????'?? was a common admonition, oh, say 40 years ago. Today, lighten up applies to installation of greenroofs.

To lighten the weight of the green roof being built on the Indianapolis-Marion County Central Library, some 20,000 square feet of polystyrene foam will be the base on which 8-12 inches of topsoil will be placed.

Polystyrene foam is sturdy, a good insulator and weighs only a tenth as much as dirt of the same thickness. It?EUR??,,????'???s a simple equation: More foam and less soil will lighten the load considerably and allow smaller diameter garage columns to support the roof for the garage below, while freeing up garage space. This is a very good thing, considering cracks in the cement in the garage roof were noted.

Foam is getting to be a common sight around Indianapolis. It was also used on the rooftop garage of the Eiteljorg Museum and will be installed at the Clarian Cancer Center. Soldier Field in Chicago used 3-8-in. thick polystyrene foam for its 57 acres of green parkland next to the stadium, beneath which is four-stories of underground parking.