What type of insulation is commonly used for attics in residential buildings?

The choice of "all of the above" is the correct answer because each type of insulation listed—fiberglass batt, cellulose, and spray foam—has qualities that make it suitable for use in attics of residential buildings.

Fiberglass batt insulation is popular due to its affordability, effectiveness, and ease of installation, making it a common choice for DIY projects. It's available in pre-cut panels that fit between standard joist spaces.

Cellulose insulation is made from recycled paper products and treated for fire resistance. It is typically blown into attics, providing excellent thermal performance and also reducing air leaks, making it an environmentally friendly option.

Spray foam insulation is a more modern solution that expands on application, filling gaps and creating an airtight seal. This type of insulation can offer superior energy efficiency as it minimizes heat loss, but it can also be more expensive.

Each of these insulation types has unique benefits that can contribute to energy efficiency, temperature regulation, and soundproofing in a home, which is why it’s appropriate to recognize that all listed options are commonly used in attic insulation.