When can spray foam be installed?

Spray foam insulation is professionally installed at the same point in the construction cycle as other types of insulation. That is, it should be installed after the rough plumbing, electrical wiring, and heating and air conditioning ducts have been installed, but before the interior walls are completed in new home construction. In some cases spray foam also can be applied in older homes, to the inside of roofs and under floors after construction has been completed.