There is no one-size-fits-all answer to this question, as the best way to install roof insulation will vary depending on the type of insulation you are using and the type of roofing material you have. However, in general, you will want to install insulation between the roofing material and the roof sheathing, and then seal any gaps or crevices with caulk or weatherstripping. You may also want to consider installing a radiant barrier on the underside of your roof sheathing to further improve your home's energy efficiency.

There are a few different ways to install roof insulation, but the most common is to use batts or rolls of insulation. The insulation is then either stapled or taped to the underside of the roof decking. Another common method is to blow in insulation using a machine that pumps it through a hose. This type of insulation usually costs more, but it can be installed in areas that are difficult to reach with batt or roll insulation.