They are called etfe cushions.
Etfe roof disadvantages.
Not as transparent as glass.
Ethylene tetrafluoroethylene etfe is a fluorine based plastic polymer that offers a creative and lightweight alternative to glass.
Metal roofs are a significant investment for homeowners.
Disadvantages of metal roofing.
However etfe foil cushions offer some benefits over glass.
Etfe cushions are finally being recognized as a striking piece of architecture in themselves not just being chosen to form roof structures and rooflights they can be used to create striking canopies.
Etfe is a very flexible material and is able to cope with large deformations before breakage.
Blurring the division between the inside and the outside somewhat they are as much a feature in themselves as a method of construction.
As being prestressed it can accomodate the live loads.
Creep is very high.
Both systems provide some capabilities like thermal insulation or light translucency.
Developed over 40 years ago by dupont etfe has similar light transmission to glass but at just 1 of the weight.
Disadvantages of etfe foil.
The most used technology consist of two or more layer inflated with dry air.
The crystallinity of etfe ranges from 40 to 60 and it has a melting temperature of 225 300 c depending on the comonomer ratio and the processing method further the ratio of the two monomers are varied to obtain several grades of etfe with optimized properties for specific end applications.
Relatively weak for a membrane material.
Disadvantages of etfe foil.
The swiss architecture team of jacques herzog and pierre de meuron created a sculpted look for the allianz arena 2005 one of the most beautiful etfe structures in münchen.
A photo journey of etfe architecture quickly dispels the notion that this is a simple plastic cladding material you might put over your roof or boat on a rainy day.
Properties change with temperature.
Etfe copolymers are basically alternating copolymers and in the molecular formula they are.
There is no doubt in the fact that glass is the most clear most transparent material but there are many other disadvantages that are associated with this material.
Cushions distort the view.
Elongations of 200 300 are possible.
In the unlikely case of a power failure the air handling unit will cut out.
Materials can range from 7 00 to 9 00 per square foot and the installation of a metal roof can cost between 21 000 to 50 000.
The cushions are kept continually inflated at a predefined pressure by a small air handling unit or ahus connected to a control panel which inflates monitors and maintains the pressure in each individual cushion.
Benefits of an etfe roof etfe has started ruling the world of transparent materials which once glass was.
