The second and third methods also have their advantages. Polyurethane spraying is not subjected to the combustion process, which affects the better on fire safety. In addition, polyurethane is an environmentally friendly material that is not deceived and the effects of bacteria. The same can be said about polystyrene foam, which not only does not pass moisture, but also protects wooden walls from malicious insects. And applying polyurethane spraying is generally a fairly simple and entertaining process.