There are various types of air barriers available, each with its unique properties and applications. Some common types include:

• Sheet materials: These are flexible or rigid sheets that can be fastened to the exterior or interior of a building's envelope. Examples include house wraps, building papers, and rigid foam insulation.
• Fluid-applied barriers: These liquid materials are applied as a coating, either sprayed or rolled on, and cure to form a continuous, seamless air barrier. Fluid-applied barriers can be made from materials like acrylic, silicone, or polyurethane.
• Boardstock materials: Boardstock materials are rigid panels, typically made from foam, gypsum, or fiberboard, that can be installed on the interior or exterior of a building.
• Air barrier systems: These systems are a combination of materials and components that work together to create a continuous air barrier, including tapes, sealants, and membranes.

It's essential to understand the specific requirements of a project and the properties of each air barrier type when choosing the most suitable option for your application.