Before you proceed with that roof installation or roof replacement, it would be useful for you to know some basics of roof insulation. Without proper roof insulation, your energy costs could go up unnecessarily.
There are two basic types of roofing insulation: reflective and bulk.
Reflective roof insulation material is more of a cooling type of insulation as it reflects 97% of the radiant heat off the roof keeping high temperatures out. Its components are aluminum foil, foam, and plastic bubble sheet or fiberglass.
Bulk roof insulation materials are of three kinds: batts and blankets, rigid foam, and sprayed polyurethane foam. Batts and blankets, the most common kind, are either of fiberglass, mineral wool, sheep’s wool, or cotton.
The ones made of fiberglass are widely available and come in standard thickness and width. It can be itchy to DIY install so you will need protective wear. Its Phenol formaldehyde component is an environmental and health issue as it has been linked to cancer.
The wool kind is more fire-resistant than fiberglass and does not cause itching. But it is not readily available and tends to retain moisture that could lead to molds.
Cotton batts are easy to cut and are available in easily handled rolls. The downside is that they aren’t readily available and are pricier than other batts.
Another kind of bulk insulation is rigid foam. This material lasts longer and does not absorb moisture, making it ideal for roofs.
Finally, there’s the sprayed polyurethane foam that’s ideal for metal roofs, sealing out air and moisture. A disadvantage with this material, though, is that it requires a pro to apply this kind of insulation.
For a complete and weather-proof roof insulation system, a combination of reflective and bulk insulation materials are usually applied by roofing professionals.