Low Expansion Foam Tips:
Since the role of low expansion foam is air sealing, not insulation, more is not always better. Just a bead of foam, enough to close the gap and stop air movement, will generally be sufficient. Because low expansion foam requires moisture to cure, when the air is dry, a quick mist of water to the area before foaming will insure a better cure of the foam.
The image to the right (click to enlarge) is a graphic developed by the United States Environmental Protection Agency to highlight common locations of air leakage.