You should start by preparing your attic space. First, check and clear the area where the baffles will be installed, removing any old insulation from the edges if necessary. For more information, check out our guide https://www.greenattic.com/blogs/how-to-install-attic-baffles
The 3.5 inch thick R-15 insulation offers 36% more R-value compared to the standard R-11 fiberglass insulation. It features a kraft facing that must not be exposed as it can burn. Ensure the facing is in substantial contact with the finishing material and protect it from open flames or other heat sources.
For a basement ceiling, fiberglass batt insulation is commonly recommended due to its effectiveness in preventing heat transfer and its ability to absorb sound. This type of insulation is available in pre-cut panels that fit easily between ceiling joists, making it relatively simple to install.