The recommended insulation for most attics is about R-38 or 10 to 14 inches deep, depending on the type of insulation you choose. BTW, is your hatch insulated, too? Use 4-inch-thick foam board glued to the top. Related Share This Memorial Day How to Enlarge Space with Color Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Δ