For more complicated insulation projects, like spray foam, it's best to consult with a professional.)
( Note: Since there are many different types of insulation to pick from these days and your choice will likely be influenced by your climate and the type of home you live in, DIY insulation is usually only practical when you're dealing with loose-fill or batts. For more complicated insulation projects, like spray foam, it's best to consult with a professional.)